diff --git a/apps/webapp/app/env.server.ts b/apps/webapp/app/env.server.ts
index cabe0159a6..291a074a2f 100644
--- a/apps/webapp/app/env.server.ts
+++ b/apps/webapp/app/env.server.ts
@@ -1746,6 +1746,10 @@ const EnvironmentSchema = z
     RUN_OPS_MINT_ENABLED: BoolEnv.default(false),
     RUN_OPS_MINT_FLAG_CACHE_TTL_MS: z.coerce.number().int().default(30_000),
     RUN_OPS_MINT_FLAG_CACHE_MAX_ENTRIES: z.coerce.number().int().default(10_000),
+    // Deterministic wall-clock cutover after a runOpsMintKind flip. Must exceed the sum
+    // of RUN_OPS_MINT_FLAG_CACHE_TTL_MS and the control-plane cache TTL so every process
+    // (stale or fresh) resolves to the same kind for the whole window. See mintFlipGrace.ts.
+    RUN_OPS_MINT_FLIP_GRACE_MS: z.coerce.number().int().default(90_000),
 
     // Session replication (Postgres → ClickHouse sessions_v1). Shares Redis
     // with the runs replicator for leader locking but has its own slot and
diff --git a/apps/webapp/app/presenters/v3/ApiBatchResultsPresenter.server.ts b/apps/webapp/app/presenters/v3/ApiBatchResultsPresenter.server.ts
index 0e04e909eb..c9179d5912 100644
--- a/apps/webapp/app/presenters/v3/ApiBatchResultsPresenter.server.ts
+++ b/apps/webapp/app/presenters/v3/ApiBatchResultsPresenter.server.ts
@@ -1,4 +1,5 @@
 import type { BatchTaskRunExecutionResult } from "@trigger.dev/core/v3";
+import { ownerEngine } from "@trigger.dev/core/v3/isomorphic";
 import {
   $replica,
   type PrismaClientOrTransaction,
@@ -8,7 +9,6 @@ import {
 import type { TaskRunWithAttempts } from "~/models/taskRun.server";
 import { executionResultForTaskRun } from "~/models/taskRun.server";
 import type { AuthenticatedEnvironment } from "~/services/apiAuth.server";
-import { readThroughRun } from "~/v3/runOpsMigration/readThrough.server";
 import { runStore as defaultRunStore } from "~/v3/runStore.server";
 import { BasePresenter } from "./basePresenter.server";
 
@@ -43,11 +43,14 @@ const memberRunSelect = {
 } as const;
 
 /**
- * Split on: the batch row + its item rows resolve new-run-ops first, then the LEGACY RUN-OPS
- * READ REPLICA ONLY (never the legacy primary — there is no such handle); each member run is
- * hydrated independently via readThroughRun keyed on the member runId, so a batch whose members
- * span migrated + abandoned runs returns the complete reachable set (the batch-spanning-the-line
- * read; the dangling-reference termination gate is a separate, adjacent unit).
+ * Split on: the batch row + its members resolve new-run-ops first, then the LEGACY RUN-OPS READ
+ * REPLICA ONLY (never the legacy primary — there is no such handle). Members hydrate via ONE
+ * grouped read against `newClient` for the whole id set, then ONE grouped read against
+ * `legacyReplica` for just the misses that could still be legacy-resident — the same
+ * residency-partitioned shape as the old per-member read-through, but batched instead of fanned
+ * out one query per member. A batch whose members span migrated + abandoned runs returns the
+ * complete reachable set (the batch-spanning-the-line read; the dangling-reference termination
+ * gate is a separate, adjacent unit).
  *
  * Split off (single-DB / self-host): one passthrough read for the batch row + a single store
  * id-set hydrate for the members — no legacy read, no known-migrated probe, no second connection.
@@ -133,7 +136,7 @@ export class ApiBatchResultsPresenter extends BasePresenter {
   // Split: resolve the batch row new-first then off the legacy READ REPLICA only (a batch id may
   // be cuid or run-ops id, and a cuid-shaped id can still have been backfilled onto NEW, so id-shape
   // residency is not authoritative for the row — the new-first-then-legacy probe is), then
-  // hydrate every member run independently via the per-run read-through primitive.
+  // hydrate every member run in ONE grouped new-then-legacy read.
   async #callSplit(
     friendlyId: string,
     env: AuthenticatedEnvironment
@@ -175,41 +178,35 @@ export class ApiBatchResultsPresenter extends BasePresenter {
       };
     }
 
-    const readMemberRun = (client: PrismaClientOrTransaction, taskRunId: string) =>
-      client.taskRun.findFirst({
-        where: { id: taskRunId },
-        select: memberRunSelect,
-      }) as Promise<TaskRunWithAttempts | null>;
-
-    // Per-member fan-out: each member may live on a different DB, so a single nested include cannot
-    // cross the seam. Promise.all preserves batchRun.items order, unchanged from today.
-    const memberResults = await Promise.all(
-      batchRun.items.map(async (item) => {
-        const result = await readThroughRun<TaskRunWithAttempts>({
-          runId: item.taskRunId,
-          environmentId: env.id,
-          readNew: (client) => readMemberRun(client, item.taskRunId),
-          readLegacy: (replica) => readMemberRun(replica, item.taskRunId),
-          deps: {
-            splitEnabled: true,
-            // Pass the SAME resolved handles the batch row used, so the batch row and its members
-            // never resolve against different DBs. (Letting these fall through to readThroughRun's
-            // own module-level defaults would diverge from the batch read's `?? this._replica`.)
-            newClient,
-            legacyReplica,
-            isPastRetention: this.readThrough?.isPastRetention,
-          },
-        });
+    const taskRunIds = batchRun.items.map((item) => item.taskRunId);
 
-        // not-found / past-retention members are omitted (matches today's drop-undefined behavior);
-        // the dangling-reference termination gate (separate unit) governs whether that's permitted.
-        if (result.source === "not-found" || result.source === "past-retention") {
-          return undefined;
-        }
+    const newRows = (await newClient.taskRun.findMany({
+      where: { id: { in: taskRunIds } },
+      select: memberRunSelect,
+    })) as TaskRunWithAttempts[];
+    const runsById = new Map(newRows.map((run) => [run.id, run]));
 
-        return executionResultForTaskRun(result.value);
-      })
+    // A run-ops id can only live on NEW, so only misses that AREN'T run-ops-shaped are candidates
+    // for the legacy probe — mirrors readThroughRun's per-id "NEW residency skips legacy" rule.
+    const legacyCandidateIds = taskRunIds.filter(
+      (id) => !runsById.has(id) && ownerEngine(id) !== "NEW"
     );
+    if (legacyCandidateIds.length > 0) {
+      const legacyRows = (await legacyReplica.taskRun.findMany({
+        where: { id: { in: legacyCandidateIds } },
+        select: memberRunSelect,
+      })) as TaskRunWithAttempts[];
+      for (const run of legacyRows) {
+        runsById.set(run.id, run);
+      }
+    }
+
+    // not-found members are omitted (matches today's drop-undefined behavior); the
+    // dangling-reference termination gate (separate unit) governs whether that's permitted.
+    const memberResults = batchRun.items.map((item) => {
+      const run = runsById.get(item.taskRunId);
+      return run ? executionResultForTaskRun(run) : undefined;
+    });
 
     return {
       id: batchRun.friendlyId,
diff --git a/apps/webapp/app/presenters/v3/ApiRetrieveRunPresenter.server.ts b/apps/webapp/app/presenters/v3/ApiRetrieveRunPresenter.server.ts
index a5c71a5555..c6a14a4492 100644
--- a/apps/webapp/app/presenters/v3/ApiRetrieveRunPresenter.server.ts
+++ b/apps/webapp/app/presenters/v3/ApiRetrieveRunPresenter.server.ts
@@ -164,17 +164,13 @@ export class ApiRetrieveRunPresenter {
         collect(child.lockedToVersionId);
       }
 
+      const lockedWorkersByVersionId =
+        await controlPlaneResolver.resolveRunLockedWorkersByVersionIds([...distinctVersionIds]);
       const versionById = new Map<string, string | null>(
-        await Promise.all(
-          [...distinctVersionIds].map(
-            async (id) =>
-              [
-                id,
-                (await controlPlaneResolver.resolveRunLockedWorker({ lockedToVersionId: id }))
-                  ?.lockedToVersion?.version ?? null,
-              ] as const
-          )
-        )
+        [...distinctVersionIds].map((id) => [
+          id,
+          lockedWorkersByVersionId.get(id)?.lockedToVersion?.version ?? null,
+        ])
       );
 
       const resolveVersion = (id: string | null): { version: string } | null => {
diff --git a/apps/webapp/app/presenters/v3/WaitpointPresenter.server.ts b/apps/webapp/app/presenters/v3/WaitpointPresenter.server.ts
index 74f0c06fdd..29ef066572 100644
--- a/apps/webapp/app/presenters/v3/WaitpointPresenter.server.ts
+++ b/apps/webapp/app/presenters/v3/WaitpointPresenter.server.ts
@@ -11,6 +11,12 @@ import { waitpointStatusToApiStatus } from "./WaitpointListPresenter.server";
 
 export type WaitpointDetail = NonNullable<Awaited<ReturnType<WaitpointPresenter["call"]>>>;
 
+// Single-sourced display bound for a waitpoint's connected run friendlyIds.
+export const CONNECTED_RUNS_DISPLAY_LIMIT = 5;
+
+// Over-read connection rows on the FK-free dedicated join so danglers don't cost a display slot.
+export const CONNECTED_RUNS_CONNECTION_SCAN_LIMIT = CONNECTED_RUNS_DISPLAY_LIMIT * 5;
+
 export class WaitpointPresenter extends BasePresenter {
   constructor(
     prisma?: PrismaClientOrTransaction,
@@ -76,8 +82,7 @@ export class WaitpointPresenter extends BasePresenter {
 
   // Connected-run friendlyIds gathered across BOTH stores. The run<->waitpoint join co-locates with
   // the RUN (written on the run's DB), so the waitpoint's own store misses a cross-DB connection; we
-  // read the join on each client and resolve the run's friendlyId on that same client, then union.
-  // We never relation-select `connectedRuns`: it is not a field on the dedicated subset `Waitpoint`.
+  // read the join on each client, resolve the run's friendlyId on that same client, and union.
   async #connectedRunFriendlyIds(waitpointId: string): Promise<string[]> {
     const replica = this._replica as unknown as PrismaReplicaClient;
     const rawClients: PrismaReplicaClient[] =
@@ -91,47 +96,66 @@ export class WaitpointPresenter extends BasePresenter {
 
     const friendlyIds = new Set<string>();
     for (const client of clients) {
-      const runIds = await this.#connectedRunIdsOn(client, waitpointId);
-      if (runIds.length === 0) {
-        continue;
+      for (const friendlyId of await this.#connectedRunFriendlyIdsOn(client, waitpointId)) {
+        friendlyIds.add(friendlyId);
       }
-      const runs = await client.taskRun.findMany({
-        where: { id: { in: runIds } },
-        select: { friendlyId: true },
-        take: 5,
-      });
-      for (const run of runs) {
-        friendlyIds.add(run.friendlyId);
-      }
-      if (friendlyIds.size >= 5) {
+      if (friendlyIds.size >= CONNECTED_RUNS_DISPLAY_LIMIT) {
         break;
       }
     }
-    return Array.from(friendlyIds).slice(0, 5);
+    return Array.from(friendlyIds).slice(0, CONNECTED_RUNS_DISPLAY_LIMIT);
   }
 
-  // Schema-aware read of the run ids linked to a waitpoint: the dedicated subset uses the explicit
-  // `WaitpointRunConnection` model, the control-plane full schema the implicit `_WaitpointRunConnections`
-  // M2M (A = TaskRun.id, B = Waitpoint.id). The dedicated join delegate is absent on the full client.
-  async #connectedRunIdsOn(client: PrismaReplicaClient, waitpointId: string): Promise<string[]> {
-    const joinDelegate = (
+  // Connected-run friendlyIds for one store, via the ORM. Two indexed reads joined in memory instead
+  // of a SQL JOIN onto the (very large) TaskRun table: `id IN (...)` can only plan as a PK lookup, so
+  // the planner can never scan TaskRun.
+  //
+  // Dedicated subset: the explicit `WaitpointRunConnection` is scalar (`taskRunId`, no FK), so a
+  // connection can outlive a deleted run. We over-read connection ids, resolve runs by id (a missing
+  // id just drops out -- danglers cost no display slot), and cap at the display limit.
+  //
+  // Control-plane full schema: no queryable join delegate (implicit M2M), so we traverse the
+  // `connectedRuns` relation; it cascade-deletes with the run, so no dangler can exist.
+  async #connectedRunFriendlyIdsOn(
+    client: PrismaReplicaClient,
+    waitpointId: string
+  ): Promise<string[]> {
+    const dedicated = (
       client as unknown as {
         waitpointRunConnection?: {
           findMany: (args: unknown) => Promise<{ taskRunId: string }[]>;
         };
       }
     ).waitpointRunConnection;
-    if (joinDelegate && typeof joinDelegate.findMany === "function") {
-      const links = await joinDelegate.findMany({
+
+    if (dedicated) {
+      const connections = await dedicated.findMany({
         where: { waitpointId },
         select: { taskRunId: true },
+        take: CONNECTED_RUNS_CONNECTION_SCAN_LIMIT,
       });
-      return links.map((link) => link.taskRunId);
+      if (connections.length === 0) {
+        return [];
+      }
+      const runs = await client.taskRun.findMany({
+        where: { id: { in: connections.map((connection) => connection.taskRunId) } },
+        select: { friendlyId: true },
+        take: CONNECTED_RUNS_DISPLAY_LIMIT,
+      });
+      return runs.map((run) => run.friendlyId);
     }
-    const rows = await client.$queryRaw<{ A: string }[]>`
-      SELECT "A" FROM "_WaitpointRunConnections" WHERE "B" = ${waitpointId}
-    `;
-    return rows.map((row) => row.A);
+
+    const waitpoint = (await (
+      client.waitpoint.findFirst as (
+        args: unknown
+      ) => Promise<{ connectedRuns: { friendlyId: string }[] } | null>
+    )({
+      where: { id: waitpointId },
+      select: {
+        connectedRuns: { select: { friendlyId: true }, take: CONNECTED_RUNS_DISPLAY_LIMIT },
+      },
+    })) as { connectedRuns: { friendlyId: string }[] } | null;
+    return (waitpoint?.connectedRuns ?? []).map((run) => run.friendlyId);
   }
 
   public async call({
diff --git a/apps/webapp/app/routes/admin.api.v1.feature-flags.ts b/apps/webapp/app/routes/admin.api.v1.feature-flags.ts
index 0c668c848c..b67a9dde02 100644
--- a/apps/webapp/app/routes/admin.api.v1.feature-flags.ts
+++ b/apps/webapp/app/routes/admin.api.v1.feature-flags.ts
@@ -1,9 +1,15 @@
 import type { ActionFunctionArgs } from "@remix-run/server-runtime";
 import { json } from "@remix-run/server-runtime";
 import { prisma } from "~/db.server";
+import { env } from "~/env.server";
 import { requireAdminApiRequest } from "~/services/personalAccessToken.server";
 import { makeSetMultipleFlags } from "~/v3/featureFlags.server";
-import { validatePartialFeatureFlags } from "~/v3/featureFlags";
+import {
+  FEATURE_FLAG,
+  type FeatureFlagCatalog,
+  validatePartialFeatureFlags,
+} from "~/v3/featureFlags";
+import { stampMintKindFlip } from "~/v3/runOpsMigration/mintFlipGrace";
 
 export async function action({ request }: ActionFunctionArgs) {
   await requireAdminApiRequest(request);
@@ -24,9 +30,51 @@ export async function action({ request }: ActionFunctionArgs) {
       );
     }
 
-    const featureFlags = validationResult.data;
+    // Derived grace-stamp fields are computed server-side; never trust them from the body.
+    const {
+      runOpsMintKindPrev: _ignoredPrev,
+      runOpsMintKindFlippedAt: _ignoredFlippedAt,
+      ...requestedFlags
+    } = validationResult.data;
+
+    let flagsToWrite: Partial<FeatureFlagCatalog> = requestedFlags;
+
+    if (requestedFlags.runOpsMintKind !== undefined) {
+      // Read the current GLOBAL mint flags so the stamp is computed against the authoritative
+      // stored state, mirroring the per-org route. stampMintKindFlip writes prev/flippedAt only
+      // on a genuine global flip, and carries an in-flight stamp forward on a same-target save.
+      const existingRows = await prisma.featureFlag.findMany({
+        where: {
+          key: {
+            in: [
+              FEATURE_FLAG.runOpsMintKind,
+              FEATURE_FLAG.runOpsMintKindPrev,
+              FEATURE_FLAG.runOpsMintKindFlippedAt,
+            ],
+          },
+        },
+        select: { key: true, value: true },
+      });
+      const existingGlobal: Record<string, unknown> = {};
+      for (const row of existingRows) {
+        existingGlobal[row.key] = row.value;
+      }
+
+      // Anchor the cutover to the control-plane DB clock, not this process's wall clock.
+      const [{ now: controlPlaneNow }] = await prisma.$queryRaw<
+        { now: Date }[]
+      >`SELECT now() AS now`;
+
+      flagsToWrite = stampMintKindFlip(
+        existingGlobal,
+        { ...requestedFlags },
+        controlPlaneNow.getTime(),
+        env.RUN_OPS_MINT_FLIP_GRACE_MS
+      ) as Partial<FeatureFlagCatalog>;
+    }
+
     const setMultipleFlags = makeSetMultipleFlags(prisma);
-    const updatedFlags = await setMultipleFlags(featureFlags);
+    const updatedFlags = await setMultipleFlags(flagsToWrite);
 
     return json({
       success: true,
diff --git a/apps/webapp/app/routes/admin.api.v1.orgs.$organizationId.feature-flags.ts b/apps/webapp/app/routes/admin.api.v1.orgs.$organizationId.feature-flags.ts
index e5fd7f7963..db1524f855 100644
--- a/apps/webapp/app/routes/admin.api.v1.orgs.$organizationId.feature-flags.ts
+++ b/apps/webapp/app/routes/admin.api.v1.orgs.$organizationId.feature-flags.ts
@@ -1,10 +1,14 @@
 import type { ActionFunctionArgs, LoaderFunctionArgs } from "@remix-run/server-runtime";
 import { json } from "@remix-run/server-runtime";
+import type { Prisma } from "@trigger.dev/database";
 import { z } from "zod";
+import { env } from "~/env.server";
 import { prisma } from "~/db.server";
 import { requireAdminApiRequest } from "~/services/personalAccessToken.server";
 import { controlPlaneResolver } from "~/v3/runOpsMigration/controlPlaneResolver.server";
+import { selectMintBaselineSource, stampMintKindFlip } from "~/v3/runOpsMigration/mintFlipGrace";
 import { validatePartialFeatureFlags } from "~/v3/featureFlags";
+import { flags as getGlobalFlags } from "~/v3/featureFlags.server";
 
 const ParamsSchema = z.object({
   organizationId: z.string(),
@@ -48,20 +52,6 @@ export async function action({ request, params }: ActionFunctionArgs) {
 
   const { organizationId } = ParamsSchema.parse(params);
 
-  const organization = await prisma.organization.findFirst({
-    where: {
-      id: organizationId,
-    },
-    select: {
-      id: true,
-      featureFlags: true,
-    },
-  });
-
-  if (!organization) {
-    return json({ error: "Organization not found" }, { status: 404 });
-  }
-
   try {
     const body = await request.json();
 
@@ -77,31 +67,66 @@ export async function action({ request, params }: ActionFunctionArgs) {
       );
     }
 
-    // Merge new flags with existing flags
-    const existingFlags = organization.featureFlags
-      ? validatePartialFeatureFlags(organization.featureFlags as Record<string, unknown>)
-      : { success: false as const };
-
-    const mergedFlags = {
-      ...(existingFlags.success ? existingFlags.data : {}),
-      ...validationResult.data,
-    };
+    // Derived grace-stamp fields are computed server-side; never trust them from the body.
+    const {
+      runOpsMintKindPrev: _ignoredPrev,
+      runOpsMintKindFlippedAt: _ignoredFlippedAt,
+      ...requestedFlags
+    } = validationResult.data;
+
+    // Seed the flip baseline from the current GLOBAL mint flags so an org's FIRST per-org override
+    // is graced from the currently-effective global kind, not the hardcoded default "cuid".
+    const globalFlags = (await getGlobalFlags()) as Record<string, unknown>;
+
+    // Lock the org row for the whole read -> merge -> stamp -> write so a concurrent flag save
+    // can't clobber the grace metadata (read-then-write race). PK lookup, one row, held to commit.
+    const updatedOrganization = await prisma.$transaction(async (tx) => {
+      const rows = await tx.$queryRaw<{ featureFlags: unknown }[]>`
+        SELECT "featureFlags" FROM "Organization" WHERE "id" = ${organizationId} FOR UPDATE`;
+
+      if (rows.length === 0) {
+        return null;
+      }
+
+      const existingRaw = rows[0].featureFlags as Record<string, unknown> | null;
+      const existingResult = existingRaw
+        ? validatePartialFeatureFlags(existingRaw)
+        : ({ success: false } as const);
+      const existingData = existingResult.success ? existingResult.data : {};
+
+      // Stamp the flip from the control-plane DB clock so the grace-window cutover is anchored to
+      // one authoritative time source, not whichever webapp process handled this request.
+      const [{ now: controlPlaneNow }] = await tx.$queryRaw<{ now: Date }[]>`SELECT now() AS now`;
+
+      const mergedFlags = stampMintKindFlip(
+        selectMintBaselineSource(existingRaw, globalFlags),
+        {
+          ...existingData,
+          ...requestedFlags,
+        },
+        controlPlaneNow.getTime(),
+        env.RUN_OPS_MINT_FLIP_GRACE_MS
+      );
 
-    // Update the organization's feature flags
-    const updatedOrganization = await prisma.organization.update({
-      where: {
-        id: organizationId,
-      },
-      data: {
-        featureFlags: mergedFlags,
-      },
-      select: {
-        id: true,
-        slug: true,
-        featureFlags: true,
-      },
+      return tx.organization.update({
+        where: {
+          id: organizationId,
+        },
+        data: {
+          featureFlags: mergedFlags as Prisma.InputJsonValue,
+        },
+        select: {
+          id: true,
+          slug: true,
+          featureFlags: true,
+        },
+      });
     });
 
+    if (!updatedOrganization) {
+      return json({ error: "Organization not found" }, { status: 404 });
+    }
+
     // Org feature flags are embedded in every env of the org; drop all its cached env rows.
     controlPlaneResolver.invalidateOrganization(organizationId);
 
diff --git a/apps/webapp/app/routes/admin.api.v2.orgs.$organizationId.feature-flags.ts b/apps/webapp/app/routes/admin.api.v2.orgs.$organizationId.feature-flags.ts
index 3c62d9c7a5..0071054bd3 100644
--- a/apps/webapp/app/routes/admin.api.v2.orgs.$organizationId.feature-flags.ts
+++ b/apps/webapp/app/routes/admin.api.v2.orgs.$organizationId.feature-flags.ts
@@ -2,9 +2,11 @@ import type { ActionFunctionArgs, LoaderFunctionArgs } from "@remix-run/server-r
 import { json } from "@remix-run/server-runtime";
 import { Prisma } from "@trigger.dev/database";
 import { z } from "zod";
+import { env } from "~/env.server";
 import { prisma } from "~/db.server";
 import { requireUser } from "~/services/session.server";
 import { controlPlaneResolver } from "~/v3/runOpsMigration/controlPlaneResolver.server";
+import { selectMintBaselineSource, stampMintKindFlip } from "~/v3/runOpsMigration/mintFlipGrace";
 import { flags as getGlobalFlags } from "~/v3/featureFlags.server";
 import {
   FEATURE_FLAG,
@@ -103,34 +105,78 @@ export async function action({ request, params }: ActionFunctionArgs) {
     return json({ error: "Invalid JSON body" }, { status: 400 });
   }
 
-  let featureFlags: typeof Prisma.JsonNull | Record<string, unknown>;
-
   if (
     body === null ||
     (typeof body === "object" && !Array.isArray(body) && Object.keys(body).length === 0)
   ) {
-    featureFlags = Prisma.JsonNull;
-  } else {
-    const validationResult = validatePartialFeatureFlags(body as Record<string, unknown>);
-    if (!validationResult.success) {
-      return json(
-        { error: "Invalid feature flags", details: validationResult.error.issues },
-        { status: 400 }
-      );
+    // Clear all flags. No grace stamp (nothing to flip) and no read-then-write race.
+    try {
+      await prisma.organization.update({
+        where: { id: organizationId },
+        data: { featureFlags: Prisma.JsonNull },
+      });
+    } catch (e) {
+      if (e instanceof Prisma.PrismaClientKnownRequestError && e.code === "P2025") {
+        throw new Response("Organization not found", { status: 404 });
+      }
+      throw e;
     }
-    featureFlags = validationResult.data;
+
+    controlPlaneResolver.invalidateOrganization(organizationId);
+    return json({ success: true });
   }
 
-  try {
-    await prisma.organization.update({
+  const validationResult = validatePartialFeatureFlags(body as Record<string, unknown>);
+  if (!validationResult.success) {
+    return json(
+      { error: "Invalid feature flags", details: validationResult.error.issues },
+      { status: 400 }
+    );
+  }
+
+  // Derived grace-stamp fields are computed server-side; never trust them from the body.
+  const {
+    runOpsMintKindPrev: _ignoredPrev,
+    runOpsMintKindFlippedAt: _ignoredFlippedAt,
+    ...requestedFlags
+  } = validationResult.data;
+
+  // Seed the flip baseline from the current GLOBAL mint flags so an org's FIRST per-org override
+  // is graced from the currently-effective global kind, not the hardcoded default "cuid".
+  const globalFlags = (await getGlobalFlags()) as Record<string, unknown>;
+
+  // Lock the org row for the whole read -> stamp -> write so a concurrent flag save can't clobber
+  // the grace metadata (read-then-write race). PK lookup, one row, held to commit.
+  const updated = await prisma.$transaction(async (tx) => {
+    const rows = await tx.$queryRaw<{ featureFlags: unknown }[]>`
+      SELECT "featureFlags" FROM "Organization" WHERE "id" = ${organizationId} FOR UPDATE`;
+
+    if (rows.length === 0) {
+      return false;
+    }
+
+    const existingRaw = rows[0].featureFlags as Record<string, unknown> | null;
+
+    // Anchor the flip stamp to the control-plane DB clock (see the v1 route), not this process's.
+    const [{ now: controlPlaneNow }] = await tx.$queryRaw<{ now: Date }[]>`SELECT now() AS now`;
+
+    const stamped = stampMintKindFlip(
+      selectMintBaselineSource(existingRaw, globalFlags),
+      requestedFlags,
+      controlPlaneNow.getTime(),
+      env.RUN_OPS_MINT_FLIP_GRACE_MS
+    );
+
+    await tx.organization.update({
       where: { id: organizationId },
-      data: { featureFlags: featureFlags as Prisma.InputJsonValue },
+      data: { featureFlags: stamped as Prisma.InputJsonValue },
     });
-  } catch (e) {
-    if (e instanceof Prisma.PrismaClientKnownRequestError && e.code === "P2025") {
-      throw new Response("Organization not found", { status: 404 });
-    }
-    throw e;
+
+    return true;
+  });
+
+  if (!updated) {
+    throw new Response("Organization not found", { status: 404 });
   }
 
   // Org feature flags are embedded in every env of the org; drop all its cached env rows.
diff --git a/apps/webapp/app/v3/featureFlags.ts b/apps/webapp/app/v3/featureFlags.ts
index 637830aef0..49a18eaf35 100644
--- a/apps/webapp/app/v3/featureFlags.ts
+++ b/apps/webapp/app/v3/featureFlags.ts
@@ -19,6 +19,9 @@ export const FEATURE_FLAG = {
   computeMigrationRequireTemplate: "computeMigrationRequireTemplate",
   devBranchesEnabled: "devBranchesEnabled",
   runOpsMintKind: "runOpsMintKind",
+  // Grace-linger stamp carried alongside runOpsMintKind on flip. See mintFlipGrace.ts.
+  runOpsMintKindPrev: "runOpsMintKindPrev",
+  runOpsMintKindFlippedAt: "runOpsMintKindFlippedAt",
 } as const;
 
 export const FeatureFlagCatalog = {
@@ -54,6 +57,10 @@ export const FeatureFlagCatalog = {
   // Per-org run-ops-id mint cutover. Defaults to "cuid"; only honored when
   // RUN_OPS_MINT_ENABLED is on AND isSplitEnabled() is true.
   [FEATURE_FLAG.runOpsMintKind]: z.enum(["cuid", "runOpsId"]),
+  // Grace-linger stamp: the previously-effective kind and the flip timestamp, written
+  // by stampMintKindFlip on a genuine flip. Display-only (see ORG_LOCKED_FLAGS).
+  [FEATURE_FLAG.runOpsMintKindPrev]: z.enum(["cuid", "runOpsId"]),
+  [FEATURE_FLAG.runOpsMintKindFlippedAt]: z.string().datetime(),
 };
 
 export type FeatureFlagKey = keyof typeof FeatureFlagCatalog;
@@ -70,6 +77,8 @@ export const GLOBAL_LOCKED_FLAGS: FeatureFlagKey[] = [
 export const ORG_LOCKED_FLAGS: FeatureFlagKey[] = [
   FEATURE_FLAG.defaultWorkerInstanceGroupId,
   FEATURE_FLAG.taskEventRepository,
+  FEATURE_FLAG.runOpsMintKindPrev,
+  FEATURE_FLAG.runOpsMintKindFlippedAt,
 ];
 
 // Create a Zod schema from the existing catalog
diff --git a/apps/webapp/app/v3/runOpsMigration/controlPlaneResolver.server.test.ts b/apps/webapp/app/v3/runOpsMigration/controlPlaneResolver.server.test.ts
new file mode 100644
index 0000000000..cd08c8a077
--- /dev/null
+++ b/apps/webapp/app/v3/runOpsMigration/controlPlaneResolver.server.test.ts
@@ -0,0 +1,168 @@
+// Real control-plane (single Postgres) proof that resolving the locked-worker version for many
+// runs' distinct `lockedToVersionId`s is a GROUPED query, not one `backgroundWorker.findFirst`
+// per id. The DB is never mocked: the call-counting proxy below delegates every call to the
+// real Prisma client (the real query still runs against the real container) - it only tallies
+// how many times each model.method pair was invoked.
+import { postgresTest } from "@internal/testcontainers";
+import { describe, expect } from "vitest";
+import type { PrismaClient, PrismaReplicaClient } from "@trigger.dev/database";
+import { ControlPlaneCache } from "./controlPlaneCache.server";
+import { ControlPlaneResolver } from "./controlPlaneResolver.server";
+
+// Wraps a real Prisma client so every `client.<model>.<method>(...)` call is tallied by
+// `"<model>.<method>"` before being forwarded, unmodified, to the real delegate. No behavior is
+// faked or short-circuited - this is instrumentation, not a mock.
+function createCallCountingProxy<T extends object>(
+  client: T
+): { client: T; counts: Map<string, number> } {
+  const counts = new Map<string, number>();
+  const bump = (key: string) => counts.set(key, (counts.get(key) ?? 0) + 1);
+  const wrappedModels = new Map<string, unknown>();
+
+  const wrapModel = (model: string, delegate: object) =>
+    new Proxy(delegate, {
+      get(target, prop, receiver) {
+        const value = Reflect.get(target, prop, receiver);
+        if (typeof prop === "string" && typeof value === "function") {
+          return (...args: unknown[]) => {
+            bump(`${model}.${prop}`);
+            return (value as (...a: unknown[]) => unknown).apply(target, args);
+          };
+        }
+        return value;
+      },
+    });
+
+  const proxy = new Proxy(client, {
+    get(target, prop, receiver) {
+      const value = Reflect.get(target, prop, receiver);
+      if (
+        typeof prop === "string" &&
+        value &&
+        typeof value === "object" &&
+        typeof (value as { findMany?: unknown }).findMany === "function"
+      ) {
+        if (!wrappedModels.has(prop)) {
+          wrappedModels.set(prop, wrapModel(prop, value as object));
+        }
+        return wrappedModels.get(prop);
+      }
+      return value;
+    },
+  });
+
+  return { client: proxy as T, counts };
+}
+
+let n = 0;
+
+async function seedEnv(prisma: PrismaClient) {
+  const s = n++;
+  const organization = await prisma.organization.create({
+    data: { title: `Org ${s}`, slug: `org-${s}` },
+  });
+  const project = await prisma.project.create({
+    data: {
+      name: `P ${s}`,
+      slug: `p-${s}`,
+      externalRef: `proj_${s}`,
+      organizationId: organization.id,
+    },
+  });
+  const environment = await prisma.runtimeEnvironment.create({
+    data: {
+      type: "PRODUCTION",
+      slug: `env-${s}`,
+      projectId: project.id,
+      organizationId: organization.id,
+      apiKey: `tr_${s}`,
+      pkApiKey: `pk_${s}`,
+      shortcode: `sc_${s}`,
+    },
+  });
+  return { organization, project, environment };
+}
+
+async function seedBackgroundWorker(
+  prisma: PrismaClient,
+  ctx: { projectId: string; runtimeEnvironmentId: string },
+  version: string
+) {
+  const s = n++;
+  return prisma.backgroundWorker.create({
+    data: {
+      friendlyId: `worker_${s}`,
+      version,
+      contentHash: `hash_${s}`,
+      projectId: ctx.projectId,
+      runtimeEnvironmentId: ctx.runtimeEnvironmentId,
+      metadata: {},
+    },
+  });
+}
+
+describe("ControlPlaneResolver.resolveRunLockedWorkersByVersionIds", () => {
+  postgresTest(
+    "issues ONE grouped findMany and ZERO per-id findFirst for N distinct ids",
+    async ({ prisma }) => {
+      const { project, environment } = await seedEnv(prisma);
+      const workers = await Promise.all(
+        [0, 1, 2].map((i) =>
+          seedBackgroundWorker(
+            prisma,
+            { projectId: project.id, runtimeEnvironmentId: environment.id },
+            `2024010${i}.0`
+          )
+        )
+      );
+
+      const { client: countedReplica, counts } = createCallCountingProxy(prisma);
+
+      const resolver = new ControlPlaneResolver({
+        controlPlanePrimary: prisma,
+        controlPlaneReplica: countedReplica as unknown as PrismaReplicaClient,
+        cache: new ControlPlaneCache(),
+        splitEnabled: () => true,
+      });
+
+      const ids = workers.map((w) => w.id);
+      const result = await resolver.resolveRunLockedWorkersByVersionIds(ids);
+
+      expect(counts.get("backgroundWorker.findMany") ?? 0).toBe(1);
+      expect(counts.get("backgroundWorker.findFirst") ?? 0).toBe(0);
+
+      for (const worker of workers) {
+        expect(result.get(worker.id)?.lockedToVersion?.version).toBe(worker.version);
+      }
+    }
+  );
+
+  postgresTest("cache-hit ids issue no query at all", async ({ prisma }) => {
+    const { project, environment } = await seedEnv(prisma);
+    const worker = await seedBackgroundWorker(
+      prisma,
+      { projectId: project.id, runtimeEnvironmentId: environment.id },
+      "20240101.0"
+    );
+
+    const cache = new ControlPlaneCache();
+    const { client: countedReplica, counts } = createCallCountingProxy(prisma);
+
+    const resolver = new ControlPlaneResolver({
+      controlPlanePrimary: prisma,
+      controlPlaneReplica: countedReplica as unknown as PrismaReplicaClient,
+      cache,
+      splitEnabled: () => true,
+    });
+
+    // Warm the cache.
+    await resolver.resolveRunLockedWorkersByVersionIds([worker.id]);
+    expect(counts.get("backgroundWorker.findMany") ?? 0).toBe(1);
+
+    // Second call for the same id is served entirely from cache - no query at all.
+    const result = await resolver.resolveRunLockedWorkersByVersionIds([worker.id]);
+    expect(counts.get("backgroundWorker.findMany") ?? 0).toBe(1);
+    expect(counts.get("backgroundWorker.findFirst") ?? 0).toBe(0);
+    expect(result.get(worker.id)?.lockedToVersion?.version).toBe(worker.version);
+  });
+});
diff --git a/apps/webapp/app/v3/runOpsMigration/controlPlaneResolver.server.ts b/apps/webapp/app/v3/runOpsMigration/controlPlaneResolver.server.ts
index fb903bc8ea..d6a706c966 100644
--- a/apps/webapp/app/v3/runOpsMigration/controlPlaneResolver.server.ts
+++ b/apps/webapp/app/v3/runOpsMigration/controlPlaneResolver.server.ts
@@ -70,6 +70,15 @@ function lockedWorkerKey(lockedById?: string | null, lockedToVersionId?: string
   return `${lockedById ?? "_"}:${lockedToVersionId ?? "_"}`;
 }
 
+type LockedToVersionRow = {
+  id: string;
+  version: string;
+  sdkVersion: string;
+  runtime: string | null;
+  runtimeVersion: string | null;
+  supportsLazyAttempts: boolean;
+};
+
 export class ControlPlaneResolver {
   private readonly controlPlanePrimary: PrismaClient;
   private readonly controlPlaneReplica: PrismaReplicaClient;
@@ -243,6 +252,87 @@ export class ControlPlaneResolver {
     };
   }
 
+  /**
+   * Grouped counterpart to `resolveRunLockedWorker({ lockedToVersionId })`: resolves the
+   * `lockedToVersion` for many distinct BackgroundWorker ids with ONE `findMany` for the
+   * cache misses (BackgroundWorker is control-plane only, no run-ops residency split), instead
+   * of one `findFirst` per id. Cache keys/shape match `resolveRunLockedWorker`'s
+   * `lockedById=undefined` slot, so entries populated here are reused by that method and
+   * vice versa.
+   */
+  async resolveRunLockedWorkersByVersionIds(
+    ids: string[]
+  ): Promise<Map<string, ResolvedRunLockedWorker | null>> {
+    const result = new Map<string, ResolvedRunLockedWorker | null>();
+    const uniqueIds = [...new Set(ids)];
+    if (uniqueIds.length === 0) {
+      return result;
+    }
+
+    if (!this.splitEnabled()) {
+      const rows = await this.#queryLockedToVersionRows(this.controlPlanePrimary, uniqueIds);
+      for (const id of uniqueIds) {
+        result.set(id, this.#toResolvedRunLockedWorker(rows.get(id)));
+      }
+      return result;
+    }
+
+    const misses: string[] = [];
+    for (const id of uniqueIds) {
+      const cached = this.cache.getLockedWorker(lockedWorkerKey(undefined, id));
+      if (cached !== undefined) {
+        result.set(id, cached);
+      } else {
+        misses.push(id);
+      }
+    }
+
+    if (misses.length > 0) {
+      const rows = await this.#queryLockedToVersionRows(this.controlPlaneReplica, misses);
+      for (const id of misses) {
+        const value = this.#toResolvedRunLockedWorker(rows.get(id));
+        this.cache.setLockedWorker(lockedWorkerKey(undefined, id), value);
+        result.set(id, value);
+      }
+    }
+
+    return result;
+  }
+
+  async #queryLockedToVersionRows(
+    client: CpClient,
+    ids: string[]
+  ): Promise<Map<string, LockedToVersionRow>> {
+    const rows = await client.backgroundWorker.findMany({
+      where: { id: { in: ids } },
+      select: {
+        id: true,
+        version: true,
+        sdkVersion: true,
+        runtime: true,
+        runtimeVersion: true,
+        supportsLazyAttempts: true,
+      },
+    });
+    return new Map(rows.map((row) => [row.id, row]));
+  }
+
+  #toResolvedRunLockedWorker(row: LockedToVersionRow | undefined): ResolvedRunLockedWorker | null {
+    if (!row) {
+      return null;
+    }
+    return {
+      lockedBy: null,
+      lockedToVersion: {
+        version: row.version,
+        sdkVersion: row.sdkVersion,
+        runtime: row.runtime,
+        runtimeVersion: row.runtimeVersion,
+        supportsLazyAttempts: row.supportsLazyAttempts,
+      },
+    };
+  }
+
   async resolveWorkerVersion(args: {
     environmentId: string;
     backgroundWorkerId?: string;
diff --git a/apps/webapp/app/v3/runOpsMigration/mintFlipGrace.test.ts b/apps/webapp/app/v3/runOpsMigration/mintFlipGrace.test.ts
new file mode 100644
index 0000000000..667068842f
--- /dev/null
+++ b/apps/webapp/app/v3/runOpsMigration/mintFlipGrace.test.ts
@@ -0,0 +1,322 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import {
+  effectiveMintKind,
+  readMintResolution,
+  resolveMintFlag,
+  selectMintBaselineSource,
+  stampMintKindFlip,
+  type MintFlagResolution,
+} from "./mintFlipGrace";
+
+// GRACE-LINGER: during [flippedAt, flippedAt + GRACE) every process — stale or fresh —
+// must resolve to the SAME (old) kind; at/after the cutover every process resolves to
+// the SAME (new) kind. This collapses the cross-process divergence window.
+const GRACE_MS = 90_000;
+const T = 1_000_000;
+
+describe("effectiveMintKind", () => {
+  beforeEach(() => vi.useFakeTimers());
+  afterEach(() => vi.useRealTimers());
+
+  it("returns r.kind directly when prev is missing", () => {
+    const r: MintFlagResolution = { kind: "cuid" };
+    expect(effectiveMintKind(r, T, GRACE_MS)).toBe("cuid");
+  });
+
+  it("returns r.kind directly when flippedAtMs is missing", () => {
+    const r: MintFlagResolution = { kind: "runOpsId", prev: "cuid" };
+    expect(effectiveMintKind(r, T, GRACE_MS)).toBe("runOpsId");
+  });
+
+  it("CORE: stale and fresh resolutions agree at every instant during grace, then both flip to the new kind at cutover", () => {
+    const stale: MintFlagResolution = { kind: "cuid" };
+    const fresh: MintFlagResolution = { kind: "runOpsId", prev: "cuid", flippedAtMs: T };
+
+    for (const now of [T, T + 1, T + 1_000, T + 45_000, T + GRACE_MS - 1]) {
+      const staleResolved = effectiveMintKind(stale, now, GRACE_MS);
+      const freshResolved = effectiveMintKind(fresh, now, GRACE_MS);
+      expect(staleResolved).toBe("cuid");
+      expect(freshResolved).toBe("cuid");
+    }
+
+    for (const now of [T + GRACE_MS, T + GRACE_MS + 1, T + GRACE_MS + 60_000]) {
+      expect(effectiveMintKind(fresh, now, GRACE_MS)).toBe("runOpsId");
+    }
+  });
+
+  it("boundary: exactly at flippedAt + GRACE resolves to the NEW kind", () => {
+    const fresh: MintFlagResolution = { kind: "runOpsId", prev: "cuid", flippedAtMs: T };
+    expect(effectiveMintKind(fresh, T + GRACE_MS - 1, GRACE_MS)).toBe("cuid");
+    expect(effectiveMintKind(fresh, T + GRACE_MS, GRACE_MS)).toBe("runOpsId");
+  });
+});
+
+describe("stampMintKindFlip", () => {
+  beforeEach(() => vi.useFakeTimers());
+  afterEach(() => vi.useRealTimers());
+
+  it("a genuine flip (cuid -> runOpsId) stamps prev and flippedAt", () => {
+    const existing = { runOpsMintKind: "cuid" };
+    const outgoing = { runOpsMintKind: "runOpsId" };
+    const result = stampMintKindFlip(existing, outgoing, T, GRACE_MS);
+
+    expect(result.runOpsMintKind).toBe("runOpsId");
+    expect(result.runOpsMintKindPrev).toBe("cuid");
+    expect(result.runOpsMintKindFlippedAt).toBe(new Date(T).toISOString());
+  });
+
+  it("defaults the existing effective kind to cuid when existing flags are null", () => {
+    const outgoing = { runOpsMintKind: "runOpsId" };
+    const result = stampMintKindFlip(null, outgoing, T, GRACE_MS);
+
+    expect(result.runOpsMintKind).toBe("runOpsId");
+    expect(result.runOpsMintKindPrev).toBe("cuid");
+    expect(result.runOpsMintKindFlippedAt).toBe(new Date(T).toISOString());
+  });
+
+  it("resubmitting the same target kind mid-grace carries the stamp forward untouched (does not reset the cutover clock)", () => {
+    const existing = {
+      runOpsMintKind: "runOpsId",
+      runOpsMintKindPrev: "cuid",
+      runOpsMintKindFlippedAt: new Date(T).toISOString(),
+    };
+    const now = T + 10_000;
+    const outgoing = { runOpsMintKind: "runOpsId", someOtherFlag: true };
+    const result = stampMintKindFlip(existing, outgoing, now, GRACE_MS);
+
+    expect(result.runOpsMintKind).toBe("runOpsId");
+    expect(result.runOpsMintKindPrev).toBe("cuid");
+    // Unrelated re-save: the cutover time must NOT slide forward.
+    expect(result.runOpsMintKindFlippedAt).toBe(new Date(T).toISOString());
+    expect(result.someOtherFlag).toBe(true);
+  });
+
+  it("an unchanged save after grace has elapsed carries the settled stamp forward and preserves unrelated flags", () => {
+    const existing = {
+      runOpsMintKind: "runOpsId",
+      runOpsMintKindPrev: "cuid",
+      runOpsMintKindFlippedAt: new Date(T).toISOString(),
+    };
+    const outgoing = { runOpsMintKind: "runOpsId", someOtherFlag: true };
+    const result = stampMintKindFlip(existing, outgoing, T + GRACE_MS + 5_000, GRACE_MS);
+
+    expect(result.runOpsMintKind).toBe("runOpsId");
+    expect(result.someOtherFlag).toBe(true);
+    expect(result.runOpsMintKindPrev).toBe("cuid");
+    expect(result.runOpsMintKindFlippedAt).toBe(new Date(T).toISOString());
+  });
+
+  it("a flip-back requested after the original grace has elapsed stamps prev := the new settled (now-effective) kind, timestamped now", () => {
+    const existing = {
+      runOpsMintKind: "runOpsId",
+      runOpsMintKindPrev: "cuid",
+      runOpsMintKindFlippedAt: new Date(T).toISOString(),
+    };
+    const now = T + GRACE_MS + 1_000;
+    const outgoing = { runOpsMintKind: "cuid" };
+    const result = stampMintKindFlip(existing, outgoing, now, GRACE_MS);
+
+    expect(result.runOpsMintKind).toBe("cuid");
+    expect(result.runOpsMintKindPrev).toBe("runOpsId");
+    expect(result.runOpsMintKindFlippedAt).toBe(new Date(now).toISOString());
+  });
+
+  it("a flip-back mid-grace re-stamps prev to the still-effective old kind, so it keeps serving that kind (no divergence)", () => {
+    const existing = {
+      runOpsMintKind: "runOpsId",
+      runOpsMintKindPrev: "cuid",
+      runOpsMintKindFlippedAt: new Date(T).toISOString(),
+    };
+    const now = T + 20_000;
+    const outgoing = { runOpsMintKind: "cuid" };
+    const result = stampMintKindFlip(existing, outgoing, now, GRACE_MS);
+
+    expect(result.runOpsMintKind).toBe("cuid");
+    expect(result.runOpsMintKindPrev).toBe("cuid");
+    expect(result.runOpsMintKindFlippedAt).toBe(new Date(now).toISOString());
+  });
+
+  it("leaves runOpsMintKind untouched when the save omits it (unrelated flag change: no inject, no spurious flip)", () => {
+    const existing = { runOpsMintKind: "runOpsId" };
+    const outgoing: Record<string, unknown> = { someOtherFlag: true };
+    const result = stampMintKindFlip(existing, outgoing, T, GRACE_MS);
+
+    // Must not inject a default kind or stamp a flip: doing so would pin the org to an explicit
+    // per-org override and make a later global flip silently skip it.
+    expect(result.runOpsMintKind).toBeUndefined();
+    expect(result.runOpsMintKindPrev).toBeUndefined();
+    expect(result.runOpsMintKindFlippedAt).toBeUndefined();
+    expect(result.someOtherFlag).toBe(true);
+  });
+
+  it("treats a malformed existing flippedAt as no stamp", () => {
+    const existing = {
+      runOpsMintKind: "runOpsId",
+      runOpsMintKindPrev: "cuid",
+      runOpsMintKindFlippedAt: "not-a-date",
+    };
+    const outgoing = { runOpsMintKind: "runOpsId" };
+    const result = stampMintKindFlip(existing, outgoing, T, GRACE_MS);
+
+    expect(result.runOpsMintKind).toBe("runOpsId");
+    // The malformed flippedAt is carried forward verbatim, but an unparseable timestamp is
+    // inert when resolved (Date.parse -> NaN -> effectiveMintKind returns the target kind).
+    expect(result.runOpsMintKindFlippedAt).toBe("not-a-date");
+    expect(
+      effectiveMintKind({ kind: "runOpsId", prev: "cuid", flippedAtMs: NaN }, T, GRACE_MS)
+    ).toBe("runOpsId");
+  });
+});
+
+// SOURCE-CONSISTENCY: the kind and its grace stamp must come from the SAME source. A per-org
+// runOpsMintKind override wins both the kind and the stamp; with no per-org override, BOTH the
+// kind and the stamp come from the global FeatureFlag rows. Never mix (e.g. a per-org kind with
+// the global stamp), which would date a grace window against the wrong flip.
+describe("resolveMintFlag", () => {
+  it("a per-org override wins the kind AND owns the stamp, ignoring the global stamp entirely", () => {
+    const perOrg = {
+      runOpsMintKind: "runOpsId",
+      runOpsMintKindPrev: "cuid",
+      runOpsMintKindFlippedAt: new Date(T).toISOString(),
+    };
+    const global = {
+      runOpsMintKind: "cuid",
+      runOpsMintKindPrev: "runOpsId",
+      runOpsMintKindFlippedAt: new Date(T + 500_000).toISOString(),
+    };
+    expect(resolveMintFlag(perOrg, global)).toEqual({
+      kind: "runOpsId",
+      prev: "cuid",
+      flippedAtMs: T,
+    });
+  });
+
+  it("with NO per-org override, the kind AND the stamp come from the global rows (global flip is graced)", () => {
+    const global = {
+      runOpsMintKind: "runOpsId",
+      runOpsMintKindPrev: "cuid",
+      runOpsMintKindFlippedAt: new Date(T).toISOString(),
+    };
+    const resolution = resolveMintFlag({}, global);
+    expect(resolution).toEqual({ kind: "runOpsId", prev: "cuid", flippedAtMs: T });
+    // Mid-grace: a global flip resolves to the OLD kind for the whole window.
+    expect(effectiveMintKind(resolution, T + GRACE_MS - 1, GRACE_MS)).toBe("cuid");
+    expect(effectiveMintKind(resolution, T + GRACE_MS, GRACE_MS)).toBe("runOpsId");
+  });
+
+  it("a per-org override with NO per-org stamp does NOT borrow the global stamp (kind stays ungraced)", () => {
+    const perOrg = { runOpsMintKind: "runOpsId" };
+    const global = {
+      runOpsMintKind: "cuid",
+      runOpsMintKindPrev: "cuid",
+      runOpsMintKindFlippedAt: new Date(T).toISOString(),
+    };
+    expect(resolveMintFlag(perOrg, global)).toEqual({
+      kind: "runOpsId",
+      prev: undefined,
+      flippedAtMs: undefined,
+    });
+  });
+
+  it("defaults to cuid with no stamp when neither source has a kind", () => {
+    expect(resolveMintFlag({}, {})).toEqual({
+      kind: "cuid",
+      prev: undefined,
+      flippedAtMs: undefined,
+    });
+    expect(resolveMintFlag(null, null)).toEqual({
+      kind: "cuid",
+      prev: undefined,
+      flippedAtMs: undefined,
+    });
+  });
+});
+
+// #3b: an org's FIRST per-org runOpsMintKind override must be stamped against the currently
+// EFFECTIVE kind — the global FeatureFlag resolution when the org has no override yet — not the
+// hardcoded default "cuid". selectMintBaselineSource picks that same source (per-org blob if it
+// sets runOpsMintKind, else the global rows) so stampMintKindFlip's baseline (storedKind +
+// prev + carry-forward) is correct.
+describe("selectMintBaselineSource", () => {
+  it("returns the per-org blob when it sets runOpsMintKind (override owns the baseline)", () => {
+    const perOrg = { runOpsMintKind: "cuid" };
+    const global = { runOpsMintKind: "runOpsId" };
+    expect(selectMintBaselineSource(perOrg, global)).toBe(perOrg);
+  });
+
+  it("falls back to the global rows when the org has no runOpsMintKind override", () => {
+    const perOrg = { someOtherFlag: true };
+    const global = { runOpsMintKind: "runOpsId" };
+    expect(selectMintBaselineSource(perOrg, global)).toBe(global);
+  });
+
+  it("returns an empty record when neither source sets a kind", () => {
+    expect(selectMintBaselineSource(null, null)).toEqual({});
+    expect(selectMintBaselineSource({ someOtherFlag: true }, null)).toEqual({});
+  });
+});
+
+describe("first per-org override stamps prev against the effective GLOBAL kind (#3b)", () => {
+  beforeEach(() => vi.useFakeTimers());
+  afterEach(() => vi.useRealTimers());
+
+  it("global=runOpsId, org's FIRST override -> cuid: genuine flip, prev=runOpsId, graced", () => {
+    const globalFlags = { runOpsMintKind: "runOpsId" };
+    const orgExisting = {}; // no per-org override yet
+    const outgoing = { runOpsMintKind: "cuid" };
+    const result = stampMintKindFlip(
+      selectMintBaselineSource(orgExisting, globalFlags),
+      outgoing,
+      T,
+      GRACE_MS
+    );
+
+    expect(result.runOpsMintKind).toBe("cuid");
+    // Previously stamped prev="cuid" (the hardcoded default) OR skipped the flip entirely; must
+    // now be "runOpsId" (the effective global kind) so the org serves it through the grace window.
+    expect(result.runOpsMintKindPrev).toBe("runOpsId");
+    expect(result.runOpsMintKindFlippedAt).toBe(new Date(T).toISOString());
+
+    const resolution = readMintResolution(result);
+    expect(effectiveMintKind(resolution, T + GRACE_MS - 1, GRACE_MS)).toBe("runOpsId");
+    expect(effectiveMintKind(resolution, T + GRACE_MS, GRACE_MS)).toBe("cuid");
+  });
+
+  it("global=runOpsId, org's FIRST override -> runOpsId (redundant): NOT a spurious flip, no phantom regression to cuid", () => {
+    const globalFlags = { runOpsMintKind: "runOpsId" };
+    const orgExisting = {};
+    const outgoing = { runOpsMintKind: "runOpsId" };
+    const result = stampMintKindFlip(
+      selectMintBaselineSource(orgExisting, globalFlags),
+      outgoing,
+      T,
+      GRACE_MS
+    );
+
+    expect(result.runOpsMintKind).toBe("runOpsId");
+    // Previously: storedKind defaulted to "cuid", so this looked like a genuine flip and stamped
+    // prev="cuid" — making the org serve cuid during a phantom grace window (a regression).
+    expect(result.runOpsMintKindPrev).toBeUndefined();
+    expect(result.runOpsMintKindFlippedAt).toBeUndefined();
+  });
+
+  it("mid-grace global flip carried into a redundant org override keeps the global stamp", () => {
+    const globalFlags = {
+      runOpsMintKind: "runOpsId",
+      runOpsMintKindPrev: "cuid",
+      runOpsMintKindFlippedAt: new Date(T).toISOString(),
+    };
+    const orgExisting = {};
+    const outgoing = { runOpsMintKind: "runOpsId" };
+    const result = stampMintKindFlip(
+      selectMintBaselineSource(orgExisting, globalFlags),
+      outgoing,
+      T + 10_000,
+      GRACE_MS
+    );
+
+    expect(result.runOpsMintKind).toBe("runOpsId");
+    expect(result.runOpsMintKindPrev).toBe("cuid");
+    expect(result.runOpsMintKindFlippedAt).toBe(new Date(T).toISOString());
+  });
+});
diff --git a/apps/webapp/app/v3/runOpsMigration/mintFlipGrace.ts b/apps/webapp/app/v3/runOpsMigration/mintFlipGrace.ts
new file mode 100644
index 0000000000..7e2366edcd
--- /dev/null
+++ b/apps/webapp/app/v3/runOpsMigration/mintFlipGrace.ts
@@ -0,0 +1,118 @@
+import type { RunIdMintKind } from "./runOpsMintKind.server";
+
+export type { RunIdMintKind };
+
+export type MintFlagResolution = {
+  kind: RunIdMintKind;
+  prev?: RunIdMintKind;
+  flippedAtMs?: number;
+};
+
+const DEFAULT_MINT_KIND: RunIdMintKind = "cuid";
+
+// Cutover boundary. `nowMs` is the reader's wall clock but `flippedAtMs` (in `r`) is DB-clock
+// (admin routes) — so this assumes NTP-synced hosts with skew << graceMs, letting every process
+// cross [flippedAtMs, flippedAtMs + graceMs) together (OLD then NEW). Accepted residual: a badly
+// mis-synced host can cross early/late and briefly reopen a skew-wide cross-DB duplicate window.
+export function effectiveMintKind(
+  r: MintFlagResolution,
+  nowMs: number,
+  graceMs: number
+): RunIdMintKind {
+  if (r.prev === undefined || r.flippedAtMs === undefined) {
+    return r.kind;
+  }
+  return nowMs < r.flippedAtMs + graceMs ? r.prev : r.kind;
+}
+
+function readMintKind(flags: Record<string, unknown>, key: string): RunIdMintKind | undefined {
+  const value = flags[key];
+  return value === "cuid" || value === "runOpsId" ? value : undefined;
+}
+
+// Reads the { kind, prev, flippedAtMs } trio out of one flag record — either an org's
+// featureFlags override blob or the global FeatureFlag rows projected into a record. Pure.
+export function readMintResolution(
+  flags: Record<string, unknown> | null | undefined
+): MintFlagResolution {
+  const source = flags ?? {};
+  const kind = readMintKind(source, "runOpsMintKind") ?? DEFAULT_MINT_KIND;
+  const prev = readMintKind(source, "runOpsMintKindPrev");
+  const flippedAtRaw = source.runOpsMintKindFlippedAt;
+  const parsed = typeof flippedAtRaw === "string" ? Date.parse(flippedAtRaw) : NaN;
+  const flippedAtMs = Number.isNaN(parsed) ? undefined : parsed;
+  return { kind, prev, flippedAtMs };
+}
+
+// SOURCE-CONSISTENT resolution: a per-org runOpsMintKind override wins the kind AND owns the
+// grace stamp; with no per-org override, the kind AND the stamp both come from the global rows.
+// The stamp is never read from a different source than the kind, which would date a grace
+// window against the wrong flip.
+export function resolveMintFlag(
+  perOrgOverrides: Record<string, unknown> | null | undefined,
+  globalFlags: Record<string, unknown> | null | undefined
+): MintFlagResolution {
+  if (readMintKind(perOrgOverrides ?? {}, "runOpsMintKind") !== undefined) {
+    return readMintResolution(perOrgOverrides);
+  }
+  return readMintResolution(globalFlags);
+}
+
+// Picks the flag record that currently determines an org's effective mint kind: the per-org
+// override blob when it sets runOpsMintKind, otherwise the global FeatureFlag rows. Same source
+// resolveMintFlag() reads, but returned as a record so it can seed stampMintKindFlip's baseline
+// (storedKind for flip-detection, prev on a genuine flip, and stamp carry-forward). This makes an
+// org's first per-org override stamp against the effective GLOBAL kind, not the default "cuid".
+export function selectMintBaselineSource(
+  perOrgOverrides: Record<string, unknown> | null | undefined,
+  globalFlags: Record<string, unknown> | null | undefined
+): Record<string, unknown> {
+  if (readMintKind(perOrgOverrides ?? {}, "runOpsMintKind") !== undefined) {
+    return perOrgOverrides ?? {};
+  }
+  return globalFlags ?? {};
+}
+
+function resolveEffectiveFromFlags(
+  flags: Record<string, unknown> | null | undefined,
+  nowMs: number,
+  graceMs: number
+): RunIdMintKind {
+  return effectiveMintKind(readMintResolution(flags), nowMs, graceMs);
+}
+
+// Stamps a grace window only when the outgoing TARGET kind differs from the stored one (a
+// genuine flip); prev := the currently-effective kind. A save that leaves the target kind
+// unchanged carries any in-flight stamp forward, so it can't reset the cutover clock.
+export function stampMintKindFlip(
+  existingFlags: Record<string, unknown> | null | undefined,
+  outgoingFlags: Record<string, unknown>,
+  nowMs: number,
+  graceMs: number
+): Record<string, unknown> {
+  // Only act when the save actually SETS runOpsMintKind. Omitting it (an unrelated flag change)
+  // must not inject the default kind, which would pin the org and make a later global flip skip it.
+  const outgoingKind = readMintKind(outgoingFlags, "runOpsMintKind");
+  if (outgoingKind === undefined) {
+    return outgoingFlags;
+  }
+  const storedKind = readMintKind(existingFlags ?? {}, "runOpsMintKind") ?? DEFAULT_MINT_KIND;
+
+  if (outgoingKind !== storedKind) {
+    // Genuine target change: serve the currently-effective kind through the new grace window.
+    outgoingFlags.runOpsMintKindPrev = resolveEffectiveFromFlags(existingFlags, nowMs, graceMs);
+    outgoingFlags.runOpsMintKindFlippedAt = new Date(nowMs).toISOString();
+    return outgoingFlags;
+  }
+
+  const existing = existingFlags ?? {};
+  const existingPrev = existing.runOpsMintKindPrev;
+  const existingFlippedAt = existing.runOpsMintKindFlippedAt;
+  if (existingPrev !== undefined) {
+    outgoingFlags.runOpsMintKindPrev = existingPrev;
+  }
+  if (existingFlippedAt !== undefined) {
+    outgoingFlags.runOpsMintKindFlippedAt = existingFlippedAt;
+  }
+  return outgoingFlags;
+}
diff --git a/apps/webapp/app/v3/runOpsMigration/runOpsMintKind.flipLatency.test.ts b/apps/webapp/app/v3/runOpsMigration/runOpsMintKind.flipLatency.test.ts
index 0465c8d1c8..11ce521b31 100644
--- a/apps/webapp/app/v3/runOpsMigration/runOpsMintKind.flipLatency.test.ts
+++ b/apps/webapp/app/v3/runOpsMigration/runOpsMintKind.flipLatency.test.ts
@@ -2,15 +2,15 @@ import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 import { BoundedTtlCache } from "~/services/realtime/boundedTtlCache";
 import { computeRunIdMintKind, type RunIdMintKind } from "./runOpsMintKind.server";
 
-// LOCK of the CURRENT (intentional) flip-latency behavior, NOT a change request.
-// resolveRunIdMintKind caches the per-org mint kind in a process-singleton
-// BoundedTtlCache (TTL RUN_OPS_MINT_FLAG_CACHE_TTL_MS, 30000ms default) with get/set
-// and NO invalidation hook (runOpsMintKind.server.ts:38-45,56-81). So after a flag
-// flip a process keeps minting the stale kind until its cached entry expires; in
-// multi-instance prod each process expires independently. This suite reconstructs the
-// same flag fn over a real cache and pins both edges of that window.
+// LOCK of the raw per-process cache's flip-latency behavior in isolation, NOT a change
+// request. Production resolveRunIdMintKind now wraps this same staleness in a deterministic
+// wall-clock grace window (mintFlipGrace.ts) so every process resolves to the SAME effective
+// kind for the whole window, then all cross together. This raw staleness is now an
+// intentional, safe input to that resolution. computeRunIdMintKind is unaffected, so this
+// suite's assertions stand as-is.
 
-// Mirror of resolveRunIdMintKind's flag fn (runOpsMintKind.server.ts:56-81).
+// Bare cached-flag closure — deliberately NOT the production flag fn, which now layers
+// grace resolution on top (see runOpsMintKind.server.ts).
 function makeCachedFlag(
   cache: BoundedTtlCache<RunIdMintKind>,
   liveFlag: () => RunIdMintKind
diff --git a/apps/webapp/app/v3/runOpsMigration/runOpsMintKind.server.ts b/apps/webapp/app/v3/runOpsMigration/runOpsMintKind.server.ts
index 305b851bdc..90b96217e1 100644
--- a/apps/webapp/app/v3/runOpsMigration/runOpsMintKind.server.ts
+++ b/apps/webapp/app/v3/runOpsMigration/runOpsMintKind.server.ts
@@ -4,7 +4,8 @@ import { logger } from "~/services/logger.server";
 import { BoundedTtlCache } from "~/services/realtime/boundedTtlCache";
 import { singleton } from "~/utils/singleton";
 import { FEATURE_FLAG } from "~/v3/featureFlags";
-import { makeFlag } from "~/v3/featureFlags.server";
+import { DEFAULT_CP_CACHE_TTL_MS } from "./controlPlaneCache.server";
+import { effectiveMintKind, resolveMintFlag, type MintFlagResolution } from "./mintFlipGrace";
 import { isSplitEnabled } from "./splitMode.server";
 
 export type RunIdMintKind = "cuid" | "runOpsId";
@@ -34,16 +35,33 @@ export async function computeRunIdMintKind(
 }
 
 // ENV-BOUND wrapper — the only place env/$replica/isSplitEnabled are read.
-const flagFn = singleton("runOpsMintFlag", () => makeFlag($replica));
 const mintCache = singleton(
   "runOpsMintCache",
   () =>
-    new BoundedTtlCache<RunIdMintKind>(
+    new BoundedTtlCache<MintFlagResolution>(
       env.RUN_OPS_MINT_FLAG_CACHE_TTL_MS,
       env.RUN_OPS_MINT_FLAG_CACHE_MAX_ENTRIES
     )
 );
 
+// BOOT-TIME SAFETY CHECK (warning only, never throws): the grace window only collapses
+// the cross-process divergence window if it outlasts BOTH caches a flag flip has to drain
+// through — this process's own mint-flag cache AND the org-flags control-plane cache a
+// stale process might still be reading through. If it doesn't, warn loudly but keep booting.
+const controlPlaneCacheTtlMs = env.CONTROL_PLANE_CACHE_TTL_MS ?? DEFAULT_CP_CACHE_TTL_MS;
+if (env.RUN_OPS_MINT_FLIP_GRACE_MS <= env.RUN_OPS_MINT_FLAG_CACHE_TTL_MS + controlPlaneCacheTtlMs) {
+  logger.warn(
+    "[runOpsMintKind] RUN_OPS_MINT_FLIP_GRACE_MS does not exceed the sum of " +
+      "RUN_OPS_MINT_FLAG_CACHE_TTL_MS and the control-plane cache TTL; a flag flip can still " +
+      "cross-DB-duplicate a concurrent root trigger during the divergence window",
+    {
+      RUN_OPS_MINT_FLIP_GRACE_MS: env.RUN_OPS_MINT_FLIP_GRACE_MS,
+      RUN_OPS_MINT_FLAG_CACHE_TTL_MS: env.RUN_OPS_MINT_FLAG_CACHE_TTL_MS,
+      controlPlaneCacheTtlMs,
+    }
+  );
+}
+
 export async function resolveRunIdMintKind(environment: {
   organizationId: string;
   id: string;
@@ -54,10 +72,14 @@ export async function resolveRunIdMintKind(environment: {
     masterEnabled: env.RUN_OPS_MINT_ENABLED,
     splitEnabled: isSplitEnabled,
     flag: async (orgId, orgFeatureFlags) => {
-      // The cache stores only "cuid"|"runOpsId" (never undefined), so the cache's
-      // "stored-undefined == miss" caveat never applies here.
+      // The cache stores the full { kind, prev, flippedAtMs } trio (never undefined), so the
+      // cache's "stored-undefined == miss" caveat never applies here. A cache HIT still passes
+      // back through effectiveMintKind so a cached-but-stale entry crosses the grace boundary
+      // on schedule, without needing an invalidation hook.
       const cached = mintCache.get(orgId);
-      if (cached !== undefined) return cached;
+      if (cached !== undefined) {
+        return effectiveMintKind(cached, Date.now(), env.RUN_OPS_MINT_FLIP_GRACE_MS);
+      }
 
       // Hot-path pass-through: use the org flags the authenticated environment already
       // carries; only fall back to a DB read when the caller did NOT pass them (non-trigger
@@ -72,13 +94,34 @@ export async function resolveRunIdMintKind(environment: {
               })
             )?.featureFlags;
 
-      const kind = await flagFn({
-        key: FEATURE_FLAG.runOpsMintKind,
-        defaultValue: "cuid",
-        overrides: (overrides as Record<string, unknown>) ?? {},
+      const overridesRecord = (overrides as Record<string, unknown>) ?? {};
+
+      // One global read over the three mint-flag keys (kind + grace stamp), folded into the
+      // single cache-miss round-trip. This replaces the former single-key flag read, so a
+      // GLOBAL flip is now grace-stamped WITHOUT adding any new per-mint/per-resolve query.
+      // (The cache-hit branch above never touches the DB.)
+      const globalRows = await $replica.featureFlag.findMany({
+        where: {
+          key: {
+            in: [
+              FEATURE_FLAG.runOpsMintKind,
+              FEATURE_FLAG.runOpsMintKindPrev,
+              FEATURE_FLAG.runOpsMintKindFlippedAt,
+            ],
+          },
+        },
+        select: { key: true, value: true },
       });
-      mintCache.set(orgId, kind);
-      return kind;
+      const globalFlags: Record<string, unknown> = {};
+      for (const row of globalRows) {
+        globalFlags[row.key] = row.value;
+      }
+
+      // Source-consistent: a per-org override wins the kind AND its stamp; otherwise the
+      // global row wins the kind AND its stamp.
+      const resolution: MintFlagResolution = resolveMintFlag(overridesRecord, globalFlags);
+      mintCache.set(orgId, resolution);
+      return effectiveMintKind(resolution, Date.now(), env.RUN_OPS_MINT_FLIP_GRACE_MS);
     },
   });
 }
diff --git a/apps/webapp/test/apiBatchResultsPresenter.dedicatedSeam.test.ts b/apps/webapp/test/apiBatchResultsPresenter.dedicatedSeam.test.ts
new file mode 100644
index 0000000000..eb322c48a1
--- /dev/null
+++ b/apps/webapp/test/apiBatchResultsPresenter.dedicatedSeam.test.ts
@@ -0,0 +1,337 @@
+// Flow-level seam proof for ApiBatchResultsPresenter, ABOVE the run-store-level coverage in
+// internal-packages/run-store (batchItemMisroute, batchCompletionResidency). Proves the batch
+// RESULTS READ assembles correctly when one batch's members are genuinely split across the real
+// dedicated run-ops subset schema (prisma17 / RunOpsPrismaClient) and the full control-plane
+// schema (prisma14) — not a mirrored full schema on both sides. No mocks.
+import { heteroRunOpsPostgresTest } from "@internal/testcontainers";
+import type { RunOpsPrismaClient } from "@internal/run-ops-database";
+import type { PrismaClient } from "@trigger.dev/database";
+import { generateRunOpsId } from "@trigger.dev/core/v3/isomorphic";
+import { describe, expect, vi } from "vitest";
+import type { PrismaReplicaClient } from "~/db.server";
+import type { AuthenticatedEnvironment } from "~/services/apiAuth.server";
+import { ApiBatchResultsPresenter } from "~/presenters/v3/ApiBatchResultsPresenter.server";
+
+vi.setConfig({ testTimeout: 60_000 });
+
+// A prisma handle that throws on any access — proves the passthrough constructor args are never
+// touched on the split path.
+const throwingPrisma = new Proxy(
+  {},
+  {
+    get(_t, prop) {
+      throw new Error(
+        `passthrough handle must not be touched on the split path (got .${String(prop)})`
+      );
+    },
+  }
+) as unknown as PrismaReplicaClient;
+
+// 25-char cuid-shaped id, no v1 version marker at index 25 -> classifies LEGACY.
+function generateLegacyCuid(): string {
+  const alphabet = "0123456789abcdefghijklmnopqrstuvwxyz";
+  const suffix = Array.from({ length: 24 }, () => alphabet[Math.floor(Math.random() * 36)]).join(
+    ""
+  );
+  return `c${suffix}`;
+}
+
+let seedCounter = 0;
+
+// TaskRun on the full control-plane schema has real FKs into RuntimeEnvironment/Project.
+async function seedLegacyEnv(prisma14: PrismaClient, slug: string) {
+  const n = seedCounter++;
+  const organization = await prisma14.organization.create({
+    data: { title: `Org ${slug}`, slug: `org-${slug}-${n}` },
+  });
+  const project = await prisma14.project.create({
+    data: {
+      name: `Proj ${slug}`,
+      slug: `proj-${slug}-${n}`,
+      organizationId: organization.id,
+      externalRef: `ext-${slug}-${n}`,
+    },
+  });
+  const environment = await prisma14.runtimeEnvironment.create({
+    data: {
+      slug: `env-${slug}-${n}`,
+      type: "PRODUCTION",
+      projectId: project.id,
+      organizationId: organization.id,
+      apiKey: `api-${slug}-${n}`,
+      pkApiKey: `pk-${slug}-${n}`,
+      shortcode: `sc-${slug}-${n}`,
+    },
+  });
+  return { organization, project, environment };
+}
+
+type SeedCtx = Awaited<ReturnType<typeof seedLegacyEnv>>;
+
+type MemberSeed = {
+  id: string;
+  friendlyId: string;
+  status: "COMPLETED_SUCCESSFULLY" | "COMPLETED_WITH_ERRORS";
+  output?: string;
+  error?: unknown;
+};
+
+// Drop the TaskRunAttempt worker/queue FKs so attempts can be seeded without standing up
+// BackgroundWorker/TaskQueue parents — incidental to this read path.
+async function relaxLegacyAttemptFk(prisma14: PrismaClient) {
+  for (const sql of [
+    `ALTER TABLE "TaskRunAttempt" DROP CONSTRAINT IF EXISTS "TaskRunAttempt_backgroundWorkerId_fkey"`,
+    `ALTER TABLE "TaskRunAttempt" DROP CONSTRAINT IF EXISTS "TaskRunAttempt_backgroundWorkerTaskId_fkey"`,
+    `ALTER TABLE "TaskRunAttempt" DROP CONSTRAINT IF EXISTS "TaskRunAttempt_queueId_fkey"`,
+  ]) {
+    await prisma14.$executeRawUnsafe(sql);
+  }
+}
+
+async function seedLegacyMember(prisma14: PrismaClient, ctx: SeedCtx, m: MemberSeed) {
+  const run = await prisma14.taskRun.create({
+    data: {
+      id: m.id,
+      friendlyId: m.friendlyId,
+      taskIdentifier: "my-task",
+      status: m.status,
+      payload: JSON.stringify({}),
+      payloadType: "application/json",
+      traceId: m.id,
+      spanId: m.id,
+      queue: "main",
+      runtimeEnvironmentId: ctx.environment.id,
+      projectId: ctx.project.id,
+      organizationId: ctx.organization.id,
+      environmentType: "PRODUCTION",
+      engine: "V2",
+    },
+  });
+
+  await prisma14.taskRunAttempt.create({
+    data: {
+      friendlyId: `attempt_${m.id}`,
+      number: 1,
+      taskRunId: run.id,
+      backgroundWorkerId: "bw",
+      backgroundWorkerTaskId: "bwt",
+      runtimeEnvironmentId: ctx.environment.id,
+      queueId: "q",
+      status: m.status === "COMPLETED_SUCCESSFULLY" ? "COMPLETED" : "FAILED",
+      output: m.output,
+      outputType: "application/json",
+      error: m.error as any,
+    },
+  });
+
+  return run;
+}
+
+// TaskRun/TaskRunAttempt on the DEDICATED (run-ops subset) schema: runtimeEnvironmentId,
+// organizationId, projectId, backgroundWorkerId/backgroundWorkerTaskId/queueId are all
+// scalar-only there (no real relation) — no parent rows to seed, unlike the legacy side.
+async function seedNewMember(
+  prisma17: RunOpsPrismaClient,
+  ctx: { envId: string; orgId: string; projectId: string },
+  m: MemberSeed
+) {
+  await prisma17.taskRun.create({
+    data: {
+      id: m.id,
+      engine: "V2",
+      status: m.status,
+      friendlyId: m.friendlyId,
+      runtimeEnvironmentId: ctx.envId,
+      environmentType: "PRODUCTION",
+      organizationId: ctx.orgId,
+      projectId: ctx.projectId,
+      taskIdentifier: "my-task",
+      payload: JSON.stringify({}),
+      payloadType: "application/json",
+      traceContext: {},
+      traceId: m.id,
+      spanId: m.id,
+      queue: "main",
+      isTest: false,
+      taskEventStore: "taskEvent",
+      depth: 0,
+    },
+  });
+
+  await prisma17.taskRunAttempt.create({
+    data: {
+      friendlyId: `attempt_${m.id}`,
+      number: 1,
+      taskRunId: m.id,
+      backgroundWorkerId: "bw",
+      backgroundWorkerTaskId: "bwt",
+      runtimeEnvironmentId: ctx.envId,
+      queueId: "q",
+      status: m.status === "COMPLETED_SUCCESSFULLY" ? "COMPLETED" : "FAILED",
+      output: m.output,
+      outputType: "application/json",
+      error: m.error as any,
+    },
+  });
+}
+
+// BatchTaskRunItem.taskRunId is a real FK to TaskRun on the dedicated schema too. A batch seeded
+// on the dedicated DB whose items reference a LEGACY-resident (or wholly missing) member has no
+// local row for that member — drop the FK so the cross-seam item row can exist, matching the
+// physical reality of a split batch.
+async function relaxNewBatchItemFk(prisma17: RunOpsPrismaClient) {
+  await prisma17.$executeRawUnsafe(
+    `ALTER TABLE "BatchTaskRunItem" DROP CONSTRAINT IF EXISTS "BatchTaskRunItem_taskRunId_fkey"`
+  );
+}
+
+async function seedBatchOnNew(
+  prisma17: RunOpsPrismaClient,
+  envId: string,
+  friendlyId: string,
+  memberIds: string[]
+) {
+  const batch = await prisma17.batchTaskRun.create({
+    data: {
+      friendlyId,
+      runtimeEnvironmentId: envId,
+      runCount: memberIds.length,
+      runIds: [],
+      batchVersion: "runengine:v2",
+    },
+  });
+  // Items in a deterministic order so the result `items` order is assertable.
+  for (const taskRunId of memberIds) {
+    await prisma17.batchTaskRunItem.create({
+      data: { batchTaskRunId: batch.id, taskRunId, status: "COMPLETED" },
+    });
+  }
+  return batch;
+}
+
+const env = (ctx: SeedCtx) =>
+  ({
+    id: ctx.environment.id,
+    type: ctx.environment.type,
+    slug: ctx.environment.slug,
+    organizationId: ctx.organization.id,
+    organization: { slug: ctx.organization.slug, title: ctx.organization.title },
+    projectId: ctx.project.id,
+    project: { name: ctx.project.name },
+  }) as unknown as AuthenticatedEnvironment;
+
+describe("ApiBatchResultsPresenter split mode — real run-ops dedicated schema seam", () => {
+  // The core assembly proof: one batch, members genuinely split across the two physically
+  // distinct, differently-shaped DBs (dedicated subset vs full control-plane).
+  heteroRunOpsPostgresTest(
+    "a batch with members split across the dedicated NEW schema and the legacy schema returns the complete union",
+    async ({ prisma14, prisma17 }: { prisma14: PrismaClient; prisma17: RunOpsPrismaClient }) => {
+      const ctx = await seedLegacyEnv(prisma14, "split-new-legacy");
+      await relaxLegacyAttemptFk(prisma14);
+      await relaxNewBatchItemFk(prisma17);
+
+      const newMemberId = generateRunOpsId();
+      expect(newMemberId.length).toBe(26);
+      const legacyMemberId = generateLegacyCuid();
+      expect(legacyMemberId.length).toBe(25);
+
+      // NEW-resident member: lives ONLY on the dedicated run-ops schema (prisma17).
+      await seedNewMember(
+        prisma17,
+        { envId: ctx.environment.id, orgId: ctx.organization.id, projectId: ctx.project.id },
+        {
+          id: newMemberId,
+          friendlyId: "run_new_member",
+          status: "COMPLETED_SUCCESSFULLY",
+          output: JSON.stringify({ from: "new" }),
+        }
+      );
+
+      // LEGACY-resident member: lives ONLY on the full control-plane schema (prisma14).
+      await seedLegacyMember(prisma14, ctx, {
+        id: legacyMemberId,
+        friendlyId: "run_legacy_member",
+        status: "COMPLETED_WITH_ERRORS",
+        error: { type: "BUILT_IN_ERROR", name: "Err", message: "boom", stackTrace: "" },
+      });
+
+      // The batch row + items live on the NEW dedicated DB; items reference both members.
+      const batchFriendlyId = "batch_split_seam";
+      await seedBatchOnNew(prisma17, ctx.environment.id, batchFriendlyId, [
+        newMemberId,
+        legacyMemberId,
+      ]);
+
+      const presenter = new ApiBatchResultsPresenter(throwingPrisma, throwingPrisma, {
+        splitEnabled: true,
+        newClient: prisma17 as unknown as PrismaReplicaClient,
+        legacyReplica: prisma14 as unknown as PrismaReplicaClient,
+      });
+
+      const result = await presenter.call(batchFriendlyId, env(ctx));
+
+      expect(result).toBeDefined();
+      expect(result!.id).toBe(batchFriendlyId);
+      expect(result!.items).toHaveLength(2);
+
+      // Order follows item order: the NEW-resident member first, the legacy-resident second.
+      const [first, second] = result!.items;
+      expect(first).toEqual({
+        ok: true,
+        id: "run_new_member",
+        taskIdentifier: "my-task",
+        output: JSON.stringify({ from: "new" }),
+        outputType: "application/json",
+      });
+      expect(second).toMatchObject({
+        ok: false,
+        id: "run_legacy_member",
+        taskIdentifier: "my-task",
+      });
+    }
+  );
+
+  // Dangling member: an item id that resolves on NEITHER the dedicated NEW schema nor the legacy
+  // schema must be dropped from the result, not thrown — the presenter degrades to the reachable
+  // set. Give the missing id a legacy shape so it also exercises the "not NEW-shaped -> legacy
+  // candidate" branch, proving the legacy probe finding nothing doesn't throw either.
+  heteroRunOpsPostgresTest(
+    "a member id that resolves on neither the dedicated NEW schema nor the legacy schema is dropped, not thrown",
+    async ({ prisma14, prisma17 }: { prisma14: PrismaClient; prisma17: RunOpsPrismaClient }) => {
+      const ctx = await seedLegacyEnv(prisma14, "dangling");
+      await relaxNewBatchItemFk(prisma17);
+
+      const presentId = generateRunOpsId();
+      const missingId = generateLegacyCuid(); // referenced by an item but seeded on NEITHER DB
+
+      await seedNewMember(
+        prisma17,
+        { envId: ctx.environment.id, orgId: ctx.organization.id, projectId: ctx.project.id },
+        {
+          id: presentId,
+          friendlyId: "run_present",
+          status: "COMPLETED_SUCCESSFULLY",
+          output: JSON.stringify({ present: true }),
+        }
+      );
+
+      const batchFriendlyId = "batch_dangling_seam";
+      await seedBatchOnNew(prisma17, ctx.environment.id, batchFriendlyId, [presentId, missingId]);
+
+      const presenter = new ApiBatchResultsPresenter(throwingPrisma, throwingPrisma, {
+        splitEnabled: true,
+        newClient: prisma17 as unknown as PrismaReplicaClient,
+        legacyReplica: prisma14 as unknown as PrismaReplicaClient,
+      });
+
+      const result = await presenter.call(batchFriendlyId, env(ctx));
+
+      expect(result).toBeDefined();
+      expect(result!.id).toBe(batchFriendlyId);
+      // The dangling member is silently dropped; the reachable member still returns — the call
+      // must not throw despite the item referencing a run absent from both physical DBs.
+      expect(result!.items).toHaveLength(1);
+      expect(result!.items[0]).toMatchObject({ ok: true, id: "run_present" });
+    }
+  );
+});
diff --git a/apps/webapp/test/apiBatchResultsPresenter.splitNPlus1.test.ts b/apps/webapp/test/apiBatchResultsPresenter.splitNPlus1.test.ts
new file mode 100644
index 0000000000..614e112992
--- /dev/null
+++ b/apps/webapp/test/apiBatchResultsPresenter.splitNPlus1.test.ts
@@ -0,0 +1,251 @@
+// RED→GREEN: kill the #callSplit per-member N+1 in ApiBatchResultsPresenter.
+//
+// Today, #callSplit hydrates every batch member independently via `readThroughRun` inside
+// `Promise.all(batchRun.items.map(...))` — that is one (up to two, new-then-legacy) `taskRun`
+// query PER member. `#callPassthrough` already does the grouped one-query form via
+// `this.runStore.findRuns({ where: { id: { in: taskRunIds } } })`.
+//
+// The fix replaces the per-member fan-out with ONE grouped call to the RunStore's
+// `findRunsByIds` method, mirroring `#callPassthrough`. This test proves the query-count
+// reduction with a call-counting Proxy over a REAL testcontainer Postgres client: every call is
+// delegated unchanged to the real client (the DB still runs the query) — this is instrumentation,
+// not a mock.
+import { PostgresRunStore } from "@internal/run-store";
+import { postgresTest } from "@internal/testcontainers";
+import type { PrismaClient } from "@trigger.dev/database";
+import { describe, expect } from "vitest";
+import type { PrismaReplicaClient } from "~/db.server";
+import type { AuthenticatedEnvironment } from "~/services/apiAuth.server";
+import { ApiBatchResultsPresenter } from "~/presenters/v3/ApiBatchResultsPresenter.server";
+
+// 26-char run-ops v1 body: 24-char base32hex core + region char + version "1" at index 25.
+// ownerEngine classifies residency by the VERSION CHAR AT INDEX 25, not by length — a naive id
+// generator would misclassify this as LEGACY unless the last two chars are a valid region+version.
+function newRunId(c: string) {
+  return c.repeat(24) + "01";
+}
+
+type CallCounts = { findMany: number; findFirst: number };
+
+// Wrap a REAL client's `taskRun` delegate to tally findMany/findFirst calls, delegating every
+// call unchanged to the real client (the DB still runs the query — pure instrumentation).
+function countingClient(real: PrismaClient): { client: PrismaClient; counts: CallCounts } {
+  const counts: CallCounts = { findMany: 0, findFirst: 0 };
+  const countingTaskRun = new Proxy((real as any).taskRun, {
+    get(target, prop) {
+      if (prop === "findMany" || prop === "findFirst") {
+        counts[prop as "findMany" | "findFirst"]++;
+      }
+      return (target as any)[prop];
+    },
+  });
+  const client = new Proxy(real, {
+    get(target, prop) {
+      if (prop === "taskRun") {
+        return countingTaskRun;
+      }
+      return (target as any)[prop];
+    },
+  }) as PrismaClient;
+  return { client, counts };
+}
+
+let seedCounter = 0;
+
+async function seedEnv(prisma: PrismaClient, slug: string) {
+  const n = seedCounter++;
+  const organization = await prisma.organization.create({
+    data: { title: `Org ${slug}`, slug: `org-${slug}-${n}` },
+  });
+  const project = await prisma.project.create({
+    data: {
+      name: `Proj ${slug}`,
+      slug: `proj-${slug}-${n}`,
+      organizationId: organization.id,
+      externalRef: `ext-${slug}-${n}`,
+    },
+  });
+  const environment = await prisma.runtimeEnvironment.create({
+    data: {
+      slug: `env-${slug}-${n}`,
+      type: "PRODUCTION",
+      projectId: project.id,
+      organizationId: organization.id,
+      apiKey: `api-${slug}-${n}`,
+      pkApiKey: `pk-${slug}-${n}`,
+      shortcode: `sc-${slug}-${n}`,
+    },
+  });
+  return { organization, project, environment };
+}
+
+type SeedCtx = Awaited<ReturnType<typeof seedEnv>>;
+
+type MemberSeed = {
+  id: string;
+  friendlyId: string;
+  status: "COMPLETED_SUCCESSFULLY" | "COMPLETED_WITH_ERRORS";
+  output?: string;
+  error?: unknown;
+};
+
+async function seedMember(prisma: PrismaClient, ctx: SeedCtx, m: MemberSeed) {
+  const run = await prisma.taskRun.create({
+    data: {
+      id: m.id,
+      friendlyId: m.friendlyId,
+      taskIdentifier: "my-task",
+      status: m.status,
+      payload: JSON.stringify({}),
+      payloadType: "application/json",
+      traceId: m.id,
+      spanId: m.id,
+      queue: "main",
+      runtimeEnvironmentId: ctx.environment.id,
+      projectId: ctx.project.id,
+      organizationId: ctx.organization.id,
+      environmentType: "PRODUCTION",
+      engine: "V2",
+    },
+  });
+
+  await prisma.taskRunAttempt.create({
+    data: {
+      friendlyId: `attempt_${m.id}`,
+      number: 1,
+      taskRunId: run.id,
+      backgroundWorkerId: "bw",
+      backgroundWorkerTaskId: "bwt",
+      runtimeEnvironmentId: ctx.environment.id,
+      queueId: "q",
+      status: m.status === "COMPLETED_SUCCESSFULLY" ? "COMPLETED" : "FAILED",
+      output: m.output,
+      outputType: "application/json",
+      error: m.error as any,
+    },
+  });
+
+  return run;
+}
+
+// Drop the TaskRunAttempt worker/queue FKs so attempts can be seeded (their output/error is what's
+// under test) without standing up BackgroundWorker/TaskQueue parents — incidental to this read path.
+async function relaxFks(prisma: PrismaClient) {
+  for (const sql of [
+    `ALTER TABLE "TaskRunAttempt" DROP CONSTRAINT IF EXISTS "TaskRunAttempt_backgroundWorkerId_fkey"`,
+    `ALTER TABLE "TaskRunAttempt" DROP CONSTRAINT IF EXISTS "TaskRunAttempt_backgroundWorkerTaskId_fkey"`,
+    `ALTER TABLE "TaskRunAttempt" DROP CONSTRAINT IF EXISTS "TaskRunAttempt_queueId_fkey"`,
+  ]) {
+    await prisma.$executeRawUnsafe(sql);
+  }
+}
+
+async function seedBatch(
+  prisma: PrismaClient,
+  ctx: SeedCtx,
+  friendlyId: string,
+  memberIds: string[]
+) {
+  const batch = await prisma.batchTaskRun.create({
+    data: {
+      friendlyId,
+      runtimeEnvironmentId: ctx.environment.id,
+      runCount: memberIds.length,
+      runIds: [],
+      batchVersion: "runengine:v2",
+    },
+  });
+  // Items in a deterministic order so the result `items` order is assertable.
+  for (const taskRunId of memberIds) {
+    await prisma.batchTaskRunItem.create({
+      data: { batchTaskRunId: batch.id, taskRunId, status: "COMPLETED" },
+    });
+  }
+  return batch;
+}
+
+const env = (ctx: SeedCtx) =>
+  ({
+    id: ctx.environment.id,
+    type: ctx.environment.type,
+    slug: ctx.environment.slug,
+    organizationId: ctx.organization.id,
+    organization: { slug: ctx.organization.slug, title: ctx.organization.title },
+    projectId: ctx.project.id,
+    project: { name: ctx.project.name },
+  }) as unknown as AuthenticatedEnvironment;
+
+describe("ApiBatchResultsPresenter split mode — member hydration is grouped, not per-member", () => {
+  postgresTest(
+    "a batch of N members costs ONE findMany (never N findFirst) and returns the same result",
+    async ({ prisma }) => {
+      const ctx = await seedEnv(prisma, "n1");
+      await relaxFks(prisma);
+
+      const { client: countingPrisma, counts } = countingClient(prisma);
+
+      const memberIds = [newRunId("a"), newRunId("b"), newRunId("c")];
+      await seedMember(prisma, ctx, {
+        id: memberIds[0],
+        friendlyId: "run_a",
+        status: "COMPLETED_SUCCESSFULLY",
+        output: JSON.stringify({ from: "a" }),
+      });
+      await seedMember(prisma, ctx, {
+        id: memberIds[1],
+        friendlyId: "run_b",
+        status: "COMPLETED_WITH_ERRORS",
+        error: { type: "BUILT_IN_ERROR", name: "Err", message: "boom", stackTrace: "" },
+      });
+      await seedMember(prisma, ctx, {
+        id: memberIds[2],
+        friendlyId: "run_c",
+        status: "COMPLETED_SUCCESSFULLY",
+        output: JSON.stringify({ from: "c" }),
+      });
+
+      await seedBatch(prisma, ctx, "batch_n1", memberIds);
+
+      const runStore = new PostgresRunStore({
+        prisma: countingPrisma,
+        readOnlyPrisma: countingPrisma,
+      });
+
+      const presenter = new ApiBatchResultsPresenter(
+        countingPrisma,
+        countingPrisma,
+        {
+          splitEnabled: true,
+          newClient: countingPrisma as unknown as PrismaReplicaClient,
+          legacyReplica: countingPrisma as unknown as PrismaReplicaClient,
+        },
+        runStore
+      );
+
+      const result = await presenter.call("batch_n1", env(ctx));
+
+      expect(result).toBeDefined();
+      expect(result!.id).toBe("batch_n1");
+      expect(result!.items).toHaveLength(3);
+      expect(result!.items[0]).toEqual({
+        ok: true,
+        id: "run_a",
+        taskIdentifier: "my-task",
+        output: JSON.stringify({ from: "a" }),
+        outputType: "application/json",
+      });
+      expect(result!.items[1]).toMatchObject({ ok: false, id: "run_b" });
+      expect(result!.items[2]).toEqual({
+        ok: true,
+        id: "run_c",
+        taskIdentifier: "my-task",
+        output: JSON.stringify({ from: "c" }),
+        outputType: "application/json",
+      });
+
+      // The grouped-read proof: ONE findMany for the whole member set, never a findFirst per member.
+      expect(counts.findMany).toBe(1);
+      expect(counts.findFirst).toBe(0);
+    }
+  );
+});
diff --git a/apps/webapp/test/apiRetrieveRunPresenter.groupedLockedWorker.test.ts b/apps/webapp/test/apiRetrieveRunPresenter.groupedLockedWorker.test.ts
new file mode 100644
index 0000000000..1b4a200751
--- /dev/null
+++ b/apps/webapp/test/apiRetrieveRunPresenter.groupedLockedWorker.test.ts
@@ -0,0 +1,266 @@
+import { containerTest } from "@internal/testcontainers";
+import { generateRunOpsId } from "@trigger.dev/core/v3/isomorphic";
+import type { PrismaClient } from "@trigger.dev/database";
+import { beforeEach, describe, expect, vi } from "vitest";
+
+// `findRun` reads the module-level `prisma`/`$replica` (control-plane handles) both directly
+// and, transitively, via the `runStore`/`controlPlaneResolver` singletons that also import them.
+// A lazy Proxy - not a plain value - is captured by those singletons at their own (one-time)
+// construction, so pointing it at a real container client after the fact still routes every
+// call there. Not a DB mock: every call forwards to a real Postgres container.
+const dbHolder = vi.hoisted(() => ({ client: undefined as PrismaClient | undefined }));
+
+vi.mock("~/db.server", () => {
+  const proxy = new Proxy(
+    {},
+    {
+      get(_t, prop) {
+        if (!dbHolder.client) throw new Error("dbHolder.client not set for this test");
+        return (dbHolder.client as any)[prop];
+      },
+    }
+  );
+  return { prisma: proxy, $replica: proxy };
+});
+
+vi.mock("~/v3/objectStore.server", () => ({
+  generatePresignedUrl: vi.fn(async () => ({ success: false, error: "not-used" })),
+}));
+
+import { ApiRetrieveRunPresenter } from "~/presenters/v3/ApiRetrieveRunPresenter.server";
+import type { AuthenticatedEnvironment } from "~/services/apiAuth.server";
+
+vi.setConfig({ testTimeout: 60_000 });
+
+// Wraps a real Prisma client so every `client.<model>.<method>(...)` call is tallied by
+// `"<model>.<method>"` before being forwarded, unmodified, to the real delegate.
+function createCallCountingProxy(client: PrismaClient): {
+  client: PrismaClient;
+  counts: Map<string, number>;
+} {
+  const counts = new Map<string, number>();
+  const wrappedModels = new Map<string, unknown>();
+
+  const wrapModel = (model: string, delegate: object) =>
+    new Proxy(delegate, {
+      get(target, prop, receiver) {
+        const value = Reflect.get(target, prop, receiver);
+        if (typeof prop === "string" && typeof value === "function") {
+          return (...args: unknown[]) => {
+            counts.set(`${model}.${prop}`, (counts.get(`${model}.${prop}`) ?? 0) + 1);
+            return (value as (...a: unknown[]) => unknown).apply(target, args);
+          };
+        }
+        return value;
+      },
+    });
+
+  const proxy = new Proxy(client, {
+    get(target, prop, receiver) {
+      const value = Reflect.get(target, prop, receiver);
+      if (
+        typeof prop === "string" &&
+        value &&
+        typeof value === "object" &&
+        typeof (value as { findMany?: unknown }).findMany === "function"
+      ) {
+        if (!wrappedModels.has(prop)) {
+          wrappedModels.set(prop, wrapModel(prop, value as object));
+        }
+        return wrappedModels.get(prop);
+      }
+      return value;
+    },
+  });
+
+  return { client: proxy as PrismaClient, counts };
+}
+
+async function seedOrgProjectEnv(prisma: PrismaClient, suffix: string) {
+  const organization = await prisma.organization.create({
+    data: { title: `test-${suffix}`, slug: `test-${suffix}` },
+  });
+  const project = await prisma.project.create({
+    data: {
+      name: `test-${suffix}`,
+      slug: `test-${suffix}`,
+      organizationId: organization.id,
+      externalRef: `test-${suffix}`,
+    },
+  });
+  const runtimeEnvironment = await prisma.runtimeEnvironment.create({
+    data: {
+      slug: `test-${suffix}`,
+      type: "DEVELOPMENT",
+      projectId: project.id,
+      organizationId: organization.id,
+      apiKey: `tr_dev_${suffix}`,
+      pkApiKey: `pk_dev_${suffix}`,
+      shortcode: `short-${suffix}`,
+    },
+  });
+  return { organization, project, runtimeEnvironment };
+}
+
+function authEnv(
+  organization: { id: string },
+  project: { id: string; externalRef: string },
+  runtimeEnvironment: { id: string; slug: string }
+): AuthenticatedEnvironment {
+  return {
+    id: runtimeEnvironment.id,
+    slug: runtimeEnvironment.slug,
+    organizationId: organization.id,
+    organization: { id: organization.id },
+    project: { id: project.id, externalRef: project.externalRef },
+  } as unknown as AuthenticatedEnvironment;
+}
+
+async function seedBackgroundWorker(
+  prisma: PrismaClient,
+  ctx: { projectId: string; runtimeEnvironmentId: string },
+  version: string
+) {
+  return prisma.backgroundWorker.create({
+    data: {
+      friendlyId: `worker_${generateRunOpsId()}`,
+      version,
+      contentHash: `hash_${generateRunOpsId()}`,
+      projectId: ctx.projectId,
+      runtimeEnvironmentId: ctx.runtimeEnvironmentId,
+      metadata: {},
+    },
+  });
+}
+
+interface SeedRunOpts {
+  id: string;
+  friendlyId: string;
+  runtimeEnvironmentId: string;
+  projectId: string;
+  organizationId: string;
+  lockedToVersionId?: string;
+  parentTaskRunId?: string;
+  rootTaskRunId?: string;
+}
+
+async function seedRun(prisma: PrismaClient, opts: SeedRunOpts) {
+  return prisma.taskRun.create({
+    data: {
+      id: opts.id,
+      friendlyId: opts.friendlyId,
+      taskIdentifier: "my-task",
+      payload: JSON.stringify({ hello: "world" }),
+      payloadType: "application/json",
+      traceId: `trace_${opts.id}`,
+      spanId: `span_${opts.id}`,
+      queue: "task/my-task",
+      runtimeEnvironmentId: opts.runtimeEnvironmentId,
+      projectId: opts.projectId,
+      organizationId: opts.organizationId,
+      environmentType: "DEVELOPMENT",
+      engine: "V2",
+      lockedToVersionId: opts.lockedToVersionId,
+      parentTaskRunId: opts.parentTaskRunId,
+      rootTaskRunId: opts.rootTaskRunId,
+    },
+  });
+}
+
+beforeEach(() => {
+  dbHolder.client = undefined;
+});
+
+describe("ApiRetrieveRunPresenter.findRun locked-worker version resolution", () => {
+  containerTest(
+    "resolves run+parent+root+children lockedToVersion with ONE grouped query, not one per id",
+    async ({ prisma }) => {
+      const proxied = createCallCountingProxy(prisma);
+      dbHolder.client = proxied.client;
+
+      const { organization, project, runtimeEnvironment } = await seedOrgProjectEnv(
+        prisma,
+        "grouped"
+      );
+      const workerCtx = { projectId: project.id, runtimeEnvironmentId: runtimeEnvironment.id };
+
+      // Two distinct versions - `workerA` is deliberately reused across run/root/one child to
+      // prove the pre-existing dedup-by-Set still collapses to the same distinct-id count.
+      const workerA = await seedBackgroundWorker(prisma, workerCtx, "2024.1.0");
+      const workerB = await seedBackgroundWorker(prisma, workerCtx, "2024.2.0");
+      const workerC = await seedBackgroundWorker(prisma, workerCtx, "2024.3.0");
+
+      const rootId = generateRunOpsId();
+      const parentId = generateRunOpsId();
+      const runId = generateRunOpsId();
+      const childId1 = generateRunOpsId();
+      const childId2 = generateRunOpsId();
+
+      await seedRun(prisma, {
+        id: rootId,
+        friendlyId: `run_${rootId}`,
+        runtimeEnvironmentId: runtimeEnvironment.id,
+        projectId: project.id,
+        organizationId: organization.id,
+        lockedToVersionId: workerA.id,
+      });
+      await seedRun(prisma, {
+        id: parentId,
+        friendlyId: `run_${parentId}`,
+        runtimeEnvironmentId: runtimeEnvironment.id,
+        projectId: project.id,
+        organizationId: organization.id,
+        rootTaskRunId: rootId,
+        lockedToVersionId: workerB.id,
+      });
+      await seedRun(prisma, {
+        id: runId,
+        friendlyId: `run_${runId}`,
+        runtimeEnvironmentId: runtimeEnvironment.id,
+        projectId: project.id,
+        organizationId: organization.id,
+        parentTaskRunId: parentId,
+        rootTaskRunId: rootId,
+        lockedToVersionId: workerA.id,
+      });
+      await seedRun(prisma, {
+        id: childId1,
+        friendlyId: `run_${childId1}`,
+        runtimeEnvironmentId: runtimeEnvironment.id,
+        projectId: project.id,
+        organizationId: organization.id,
+        parentTaskRunId: runId,
+        rootTaskRunId: rootId,
+        lockedToVersionId: workerC.id,
+      });
+      await seedRun(prisma, {
+        id: childId2,
+        friendlyId: `run_${childId2}`,
+        runtimeEnvironmentId: runtimeEnvironment.id,
+        projectId: project.id,
+        organizationId: organization.id,
+        parentTaskRunId: runId,
+        rootTaskRunId: rootId,
+        lockedToVersionId: workerA.id,
+      });
+
+      const env = authEnv(organization, project, runtimeEnvironment);
+      const found = await ApiRetrieveRunPresenter.findRun(`run_${runId}`, env);
+
+      expect(found).not.toBeNull();
+      expect(found!.lockedToVersion?.version).toBe(workerA.version);
+      expect(found!.parentTaskRun?.lockedToVersion?.version).toBe(workerB.version);
+      expect(found!.rootTaskRun?.lockedToVersion?.version).toBe(workerA.version);
+      const versionByChildFriendlyId = new Map(
+        found!.childRuns.map((c) => [c.friendlyId, c.lockedToVersion?.version])
+      );
+      expect(versionByChildFriendlyId.get(`run_${childId1}`)).toBe(workerC.version);
+      expect(versionByChildFriendlyId.get(`run_${childId2}`)).toBe(workerA.version);
+
+      // 3 distinct lockedToVersionIds (workerA, workerB, workerC) across 5 rows -> ONE grouped
+      // findMany, ZERO per-id findFirst.
+      expect(proxied.counts.get("backgroundWorker.findMany") ?? 0).toBe(1);
+      expect(proxied.counts.get("backgroundWorker.findFirst") ?? 0).toBe(0);
+    }
+  );
+});
diff --git a/apps/webapp/test/waitpointPresenter.connectedRunsBounded.test.ts b/apps/webapp/test/waitpointPresenter.connectedRunsBounded.test.ts
new file mode 100644
index 0000000000..a8263b80e3
--- /dev/null
+++ b/apps/webapp/test/waitpointPresenter.connectedRunsBounded.test.ts
@@ -0,0 +1,236 @@
+// RED->GREEN guard: WaitpointPresenter connected-run gather must BOUND the fetch of a waitpoint's
+// connected-run ids, not just the number displayed. A "displayed count <= 5" assertion would
+// false-green (the take:5 on the run resolve already bounds the DISPLAY). Instead this captures the
+// real `taskRun.findMany` call args via a Proxy over a REAL testcontainer Postgres client (no mocks)
+// and asserts the IN-list is capped at the scan limit (danglers over-read), never unbounded.
+//
+// Exercises the dedicated-schema (Prisma `waitpointRunConnection`) branch: waitpoint + more than the
+// scan-limit connected runs seeded on the NEW dedicated run-ops client (RunOpsPrismaClient, prisma17).
+import { describe, expect, vi } from "vitest";
+
+const legacyReplicaHolder = vi.hoisted(() => ({ client: undefined as any }));
+const newClientHolder = vi.hoisted(() => ({ client: undefined as any }));
+
+vi.mock("~/db.server", async () => {
+  const { Prisma } = await import("@trigger.dev/database");
+  const lazyProxy = (holder: { client: any }, label: string) =>
+    new Proxy(
+      {},
+      {
+        get(_t, prop) {
+          if (!holder.client) {
+            throw new Error(`${label} not set for this test`);
+          }
+          return holder.client[prop];
+        },
+      }
+    );
+  const replicaProxy = lazyProxy(legacyReplicaHolder, "legacyReplicaHolder.client");
+  return {
+    prisma: replicaProxy,
+    $replica: replicaProxy,
+    runOpsNewPrisma: lazyProxy(newClientHolder, "newClientHolder.client"),
+    runOpsNewReplica: lazyProxy(newClientHolder, "newClientHolder.client"),
+    runOpsLegacyPrisma: replicaProxy,
+    runOpsLegacyReplica: replicaProxy,
+    sqlDatabaseSchema: Prisma.sql([`public`]),
+    DATABASE_SCHEMA: "public",
+  };
+});
+
+vi.mock("~/services/clickhouse/clickhouseFactoryInstance.server", () => ({
+  clickhouseFactory: {
+    getClickhouseForOrganization: async () => ({}),
+  },
+}));
+
+// Echo the runId set back as runs so the presenter's final CH hydrate never runs for real -- the
+// thing under test is the connected-run-id GATHER (the taskRun.findMany args), not this step.
+vi.mock("~/presenters/v3/NextRunListPresenter.server", () => ({
+  NextRunListPresenter: class {
+    // eslint-disable-next-line @typescript-eslint/no-unused-vars
+    constructor(..._args: unknown[]) {}
+    async call(_organizationId: string, _environmentId: string, opts: { runId?: string[] }) {
+      return {
+        runs: (opts.runId ?? []).map((friendlyId) => ({
+          friendlyId,
+          taskIdentifier: "echoed",
+        })),
+      };
+    }
+  },
+}));
+
+import { heteroRunOpsPostgresTest } from "@internal/testcontainers";
+import type { PrismaClient } from "@trigger.dev/database";
+import type { RunOpsPrismaClient } from "@internal/run-ops-database";
+import {
+  CONNECTED_RUNS_CONNECTION_SCAN_LIMIT,
+  WaitpointPresenter,
+} from "~/presenters/v3/WaitpointPresenter.server";
+
+vi.setConfig({ testTimeout: 90_000 });
+
+type SeedContext = {
+  organizationId: string;
+  projectId: string;
+  environmentId: string;
+};
+
+async function seedParents(prisma: PrismaClient, slug: string): Promise<SeedContext> {
+  const organization = await prisma.organization.create({
+    data: { title: `org-${slug}`, slug: `org-${slug}` },
+  });
+  const project = await prisma.project.create({
+    data: {
+      name: `proj-${slug}`,
+      slug: `proj-${slug}`,
+      organizationId: organization.id,
+      externalRef: `proj-${slug}`,
+    },
+  });
+  const runtimeEnvironment = await prisma.runtimeEnvironment.create({
+    data: {
+      slug: `env-${slug}`,
+      type: "DEVELOPMENT",
+      projectId: project.id,
+      organizationId: organization.id,
+      apiKey: `tr_dev_${slug}`,
+      pkApiKey: `pk_dev_${slug}`,
+      shortcode: `sc-${slug}`,
+    },
+  });
+  return {
+    organizationId: organization.id,
+    projectId: project.id,
+    environmentId: runtimeEnvironment.id,
+  };
+}
+
+async function seedWaitpoint(
+  prisma: PrismaClient | RunOpsPrismaClient,
+  ctx: SeedContext,
+  friendlyId: string
+) {
+  return (prisma as PrismaClient).waitpoint.create({
+    data: {
+      friendlyId,
+      type: "MANUAL",
+      status: "COMPLETED",
+      idempotencyKey: `idem-${friendlyId}`,
+      userProvidedIdempotencyKey: false,
+      outputType: "application/json",
+      outputIsError: false,
+      completedAt: new Date(),
+      tags: [],
+      projectId: ctx.projectId,
+      environmentId: ctx.environmentId,
+    },
+  });
+}
+
+async function seedRun(
+  prisma: PrismaClient | RunOpsPrismaClient,
+  ctx: SeedContext,
+  friendlyId: string
+) {
+  return (prisma as PrismaClient).taskRun.create({
+    data: {
+      friendlyId,
+      taskIdentifier: "my-task",
+      status: "PENDING",
+      payload: JSON.stringify({ foo: friendlyId }),
+      payloadType: "application/json",
+      traceId: friendlyId,
+      spanId: friendlyId,
+      queue: "test",
+      runtimeEnvironmentId: ctx.environmentId,
+      projectId: ctx.projectId,
+      organizationId: ctx.organizationId,
+      environmentType: "DEVELOPMENT",
+      engine: "V2",
+    },
+  });
+}
+
+// Wrap the REAL dedicated run-ops client's `taskRun.findMany` to capture the args of every call,
+// delegating unchanged to the real client (the DB still runs the query -- pure instrumentation,
+// never a mock).
+function capturingTaskRunFindMany(real: RunOpsPrismaClient): {
+  client: RunOpsPrismaClient;
+  calls: { where?: { id?: { in?: string[] } } }[];
+} {
+  const calls: { where?: { id?: { in?: string[] } } }[] = [];
+  const wrappedTaskRun = new Proxy((real as any).taskRun, {
+    get(target, prop) {
+      if (prop === "findMany") {
+        return (...args: any[]) => {
+          calls.push(args[0]);
+          return (target as any)[prop](...args);
+        };
+      }
+      return (target as any)[prop];
+    },
+  });
+  const client = new Proxy(real as object, {
+    get(target, prop) {
+      if (prop === "taskRun") {
+        return wrappedTaskRun;
+      }
+      return (target as any)[prop];
+    },
+  }) as RunOpsPrismaClient;
+  return { client, calls };
+}
+
+// Seed MORE than the scan limit so the assertion bites: an unbounded gather IN-lists all of them,
+// a correctly bounded one caps at CONNECTED_RUNS_CONNECTION_SCAN_LIMIT.
+const CONNECTED_RUN_COUNT = CONNECTED_RUNS_CONNECTION_SCAN_LIMIT + 5;
+
+describe("WaitpointPresenter bounds the connected-run-id FETCH", () => {
+  heteroRunOpsPostgresTest(
+    "a waitpoint with more connections than the scan limit caps the IN-list at the scan limit",
+    async ({ prisma14, prisma17 }) => {
+      const ctx = await seedParents(prisma14, "bounded");
+      const waitpoint = await seedWaitpoint(prisma17, ctx, "waitpoint_bounded");
+
+      const runs = await Promise.all(
+        Array.from({ length: CONNECTED_RUN_COUNT }, (_, i) => seedRun(prisma17, ctx, `run_b${i}`))
+      );
+      for (const run of runs) {
+        await prisma17.waitpointRunConnection.create({
+          data: { taskRunId: run.id, waitpointId: waitpoint.id },
+        });
+      }
+
+      legacyReplicaHolder.client = prisma14;
+      newClientHolder.client = prisma17;
+
+      const { client: countingPrisma17, calls } = capturingTaskRunFindMany(prisma17);
+
+      const presenter = new WaitpointPresenter(undefined, undefined, {
+        splitEnabled: true,
+        newClient: countingPrisma17 as unknown as PrismaClient,
+        legacyReplica: prisma14,
+      });
+
+      await presenter.call({
+        friendlyId: waitpoint.friendlyId,
+        environmentId: ctx.environmentId,
+        projectId: ctx.projectId,
+      });
+
+      // The guard: assert the FETCH (the IN-list built from the connected-run-id gather) is
+      // bounded, not just the eventual displayed count. An unbounded gather would IN-list every
+      // connection row; the dedicated branch over-reads up to CONNECTED_RUNS_CONNECTION_SCAN_LIMIT
+      // (25) so a display slot is never lost to a dangler, so the IN-list must be capped at the
+      // scan limit -- above the display limit (5), but never unbounded.
+      expect(calls.length).toBeGreaterThan(0);
+      for (const call of calls) {
+        expect(call.where?.id?.in?.length ?? 0).toBeLessThanOrEqual(
+          CONNECTED_RUNS_CONNECTION_SCAN_LIMIT
+        );
+      }
+    }
+  );
+});
diff --git a/apps/webapp/test/waitpointPresenter.controlPlane.test.ts b/apps/webapp/test/waitpointPresenter.controlPlane.test.ts
index f3513252ed..dfb8187e89 100644
--- a/apps/webapp/test/waitpointPresenter.controlPlane.test.ts
+++ b/apps/webapp/test/waitpointPresenter.controlPlane.test.ts
@@ -32,6 +32,7 @@ vi.mock("~/db.server", async () => {
     $replica: proxy,
     runOpsNewPrisma: proxy,
     sqlDatabaseSchema: Prisma.sql([`public`]),
+    DATABASE_SCHEMA: "public",
   };
 });
 
diff --git a/apps/webapp/test/waitpointPresenter.danglingConnectedRuns.test.ts b/apps/webapp/test/waitpointPresenter.danglingConnectedRuns.test.ts
new file mode 100644
index 0000000000..0c2565c545
--- /dev/null
+++ b/apps/webapp/test/waitpointPresenter.danglingConnectedRuns.test.ts
@@ -0,0 +1,199 @@
+// RED->GREEN guard: #connectedRunIdsOn used to cap the connection-id fetch at
+// CONNECTED_RUNS_DISPLAY_LIMIT BEFORE checking the runs exist. The dedicated store's
+// WaitpointRunConnection is FK-free, so dangling rows can starve out real ones within the cap.
+// The fix existence-filters AT THE QUERY (JOIN to TaskRun) so the LIMIT only ever lands on rows
+// whose run exists.
+import { describe, expect, vi } from "vitest";
+
+const legacyReplicaHolder = vi.hoisted(() => ({ client: undefined as any }));
+const newClientHolder = vi.hoisted(() => ({ client: undefined as any }));
+
+vi.mock("~/db.server", async () => {
+  const { Prisma } = await import("@trigger.dev/database");
+  const lazyProxy = (holder: { client: any }, label: string) =>
+    new Proxy(
+      {},
+      {
+        get(_t, prop) {
+          if (!holder.client) {
+            throw new Error(`${label} not set for this test`);
+          }
+          return holder.client[prop];
+        },
+      }
+    );
+  const replicaProxy = lazyProxy(legacyReplicaHolder, "legacyReplicaHolder.client");
+  return {
+    prisma: replicaProxy,
+    $replica: replicaProxy,
+    runOpsNewPrisma: lazyProxy(newClientHolder, "newClientHolder.client"),
+    runOpsNewReplica: lazyProxy(newClientHolder, "newClientHolder.client"),
+    runOpsLegacyPrisma: replicaProxy,
+    runOpsLegacyReplica: replicaProxy,
+    sqlDatabaseSchema: Prisma.sql([`public`]),
+    DATABASE_SCHEMA: "public",
+  };
+});
+
+vi.mock("~/services/clickhouse/clickhouseFactoryInstance.server", () => ({
+  clickhouseFactory: {
+    getClickhouseForOrganization: async () => ({}),
+  },
+}));
+
+vi.mock("~/presenters/v3/NextRunListPresenter.server", () => ({
+  NextRunListPresenter: class {
+    // eslint-disable-next-line @typescript-eslint/no-unused-vars
+    constructor(..._args: unknown[]) {}
+    async call(_organizationId: string, _environmentId: string, opts: { runId?: string[] }) {
+      return {
+        runs: (opts.runId ?? []).map((friendlyId) => ({
+          friendlyId,
+          taskIdentifier: "echoed",
+        })),
+      };
+    }
+  },
+}));
+
+import { heteroRunOpsPostgresTest } from "@internal/testcontainers";
+import type { PrismaClient } from "@trigger.dev/database";
+import type { RunOpsPrismaClient } from "@internal/run-ops-database";
+import {
+  CONNECTED_RUNS_DISPLAY_LIMIT,
+  WaitpointPresenter,
+} from "~/presenters/v3/WaitpointPresenter.server";
+
+vi.setConfig({ testTimeout: 90_000 });
+
+type SeedContext = {
+  organizationId: string;
+  projectId: string;
+  environmentId: string;
+};
+
+async function seedParents(prisma: PrismaClient, slug: string): Promise<SeedContext> {
+  const organization = await prisma.organization.create({
+    data: { title: `org-${slug}`, slug: `org-${slug}` },
+  });
+  const project = await prisma.project.create({
+    data: {
+      name: `proj-${slug}`,
+      slug: `proj-${slug}`,
+      organizationId: organization.id,
+      externalRef: `proj-${slug}`,
+    },
+  });
+  const runtimeEnvironment = await prisma.runtimeEnvironment.create({
+    data: {
+      slug: `env-${slug}`,
+      type: "DEVELOPMENT",
+      projectId: project.id,
+      organizationId: organization.id,
+      apiKey: `tr_dev_${slug}`,
+      pkApiKey: `pk_dev_${slug}`,
+      shortcode: `sc-${slug}`,
+    },
+  });
+  return {
+    organizationId: organization.id,
+    projectId: project.id,
+    environmentId: runtimeEnvironment.id,
+  };
+}
+
+async function seedWaitpoint(prisma: RunOpsPrismaClient, ctx: SeedContext, friendlyId: string) {
+  return (prisma as unknown as PrismaClient).waitpoint.create({
+    data: {
+      friendlyId,
+      type: "MANUAL",
+      status: "COMPLETED",
+      idempotencyKey: `idem-${friendlyId}`,
+      userProvidedIdempotencyKey: false,
+      outputType: "application/json",
+      outputIsError: false,
+      completedAt: new Date(),
+      tags: [],
+      projectId: ctx.projectId,
+      environmentId: ctx.environmentId,
+    },
+  });
+}
+
+async function seedRun(prisma: RunOpsPrismaClient, ctx: SeedContext, friendlyId: string) {
+  return (prisma as unknown as PrismaClient).taskRun.create({
+    data: {
+      friendlyId,
+      taskIdentifier: "my-task",
+      status: "PENDING",
+      payload: JSON.stringify({ foo: friendlyId }),
+      payloadType: "application/json",
+      traceId: friendlyId,
+      spanId: friendlyId,
+      queue: "test",
+      runtimeEnvironmentId: ctx.environmentId,
+      projectId: ctx.projectId,
+      organizationId: ctx.organizationId,
+      environmentType: "DEVELOPMENT",
+      engine: "V2",
+    },
+  });
+}
+
+// Inserted before the real rows so the pre-fix cap-then-check code is starved of real ids.
+const DANGLING_CONNECTION_COUNT = 10;
+const REAL_CONNECTED_RUN_COUNT = 3; // <= CONNECTED_RUNS_DISPLAY_LIMIT (5): all must show up
+
+describe("WaitpointPresenter#connectedRunIdsOn is robust to dangling (FK-free) connection rows", () => {
+  heteroRunOpsPostgresTest(
+    "returns the existing connected runs even when dangling connections precede them",
+    async ({ prisma14, prisma17 }) => {
+      const ctx = await seedParents(prisma14, "dangling");
+      const waitpoint = await seedWaitpoint(prisma17, ctx, "waitpoint_dangling");
+
+      // Dangling connections: taskRunId points at a run that was NEVER created. The dedicated
+      // `WaitpointRunConnection` model is scalar/FK-free, so this insert is legal.
+      for (let i = 0; i < DANGLING_CONNECTION_COUNT; i++) {
+        await prisma17.waitpointRunConnection.create({
+          data: { taskRunId: `nonexistent_run_${i}`, waitpointId: waitpoint.id },
+        });
+      }
+
+      // Real, existing connected runs -- created (and connected) AFTER the dangling rows.
+      const realRuns = await Promise.all(
+        Array.from({ length: REAL_CONNECTED_RUN_COUNT }, (_, i) =>
+          seedRun(prisma17, ctx, `run_dangling_real_${i}`)
+        )
+      );
+      for (const run of realRuns) {
+        await prisma17.waitpointRunConnection.create({
+          data: { taskRunId: run.id, waitpointId: waitpoint.id },
+        });
+      }
+
+      legacyReplicaHolder.client = prisma14;
+      newClientHolder.client = prisma17;
+
+      const presenter = new WaitpointPresenter(undefined, undefined, {
+        splitEnabled: true,
+        newClient: prisma17 as unknown as PrismaClient,
+        legacyReplica: prisma14,
+      });
+
+      const result = await presenter.call({
+        friendlyId: waitpoint.friendlyId,
+        environmentId: ctx.environmentId,
+        projectId: ctx.projectId,
+      });
+
+      expect(result).not.toBeNull();
+      const friendlyIds = (result?.connectedRuns ?? []).map((r) => r.friendlyId).sort();
+      expect(friendlyIds.length).toBeLessThanOrEqual(CONNECTED_RUNS_DISPLAY_LIMIT);
+      // The bug: cap-before-existence-check lets dangling rows starve out the real ones, so this
+      // fails (returns fewer than REAL_CONNECTED_RUN_COUNT, often zero) on unfixed code.
+      expect(friendlyIds).toEqual(
+        realRuns.map((r) => r.friendlyId).sort((a, b) => a.localeCompare(b))
+      );
+    }
+  );
+});
diff --git a/apps/webapp/test/waitpointPresenter.dedicatedConnectedRuns.readthrough.test.ts b/apps/webapp/test/waitpointPresenter.dedicatedConnectedRuns.readthrough.test.ts
index a71a47d53a..f8df63d7cf 100644
--- a/apps/webapp/test/waitpointPresenter.dedicatedConnectedRuns.readthrough.test.ts
+++ b/apps/webapp/test/waitpointPresenter.dedicatedConnectedRuns.readthrough.test.ts
@@ -31,6 +31,7 @@ vi.mock("~/db.server", async () => {
     runOpsLegacyPrisma: replicaProxy,
     runOpsLegacyReplica: replicaProxy,
     sqlDatabaseSchema: Prisma.sql([`public`]),
+    DATABASE_SCHEMA: "public",
   };
 });
 
diff --git a/apps/webapp/test/waitpointPresenter.readthrough.test.ts b/apps/webapp/test/waitpointPresenter.readthrough.test.ts
index a60562a950..72b794b30d 100644
--- a/apps/webapp/test/waitpointPresenter.readthrough.test.ts
+++ b/apps/webapp/test/waitpointPresenter.readthrough.test.ts
@@ -39,6 +39,7 @@ vi.mock("~/db.server", async () => {
     runOpsLegacyPrisma: replicaProxy,
     runOpsLegacyReplica: replicaProxy,
     sqlDatabaseSchema: Prisma.sql([`public`]),
+    DATABASE_SCHEMA: "public",
   };
 });
 
@@ -67,11 +68,17 @@ import { setupClickhouseReplication } from "./utils/replicationUtils";
 
 vi.setConfig({ testTimeout: 90_000 });
 
-// A read client whose waitpoint.findFirst is recorded; throws if used after being marked
-// forbidden, so we can prove a store was NEVER read. Every other access forwards to the real
-// client (so the inlined `environment` join + connectedRuns relation still resolve).
+// A read client whose waitpoint.findFirst calls are recorded, split by kind. The presenter issues
+// two shapes of waitpoint.findFirst: a HYDRATE (loads the waitpoint scalar row -- no `connectedRuns`
+// in its select) and a connectedRuns-RELATION read (control-plane branch of the connected-runs
+// gather -- select is exactly `{ connectedRuns }`). The `forbidden` guard throws ONLY on a HYDRATE,
+// so a store can be proven to never be HYDRATED while still allowing the connectedRuns cross-DB
+// union to legitimately read it (that union always touched both stores; it was invisible when the
+// old code did it via raw SQL). Every other access forwards to the real client.
 function recording(client: PrismaClient, opts: { forbidden?: boolean } = {}) {
   const calls: unknown[] = [];
+  const hydrateCalls: unknown[] = [];
+  const connectedRunsCalls: unknown[] = [];
   return {
     handle: new Proxy(client, {
       get(target, prop) {
@@ -81,8 +88,16 @@ function recording(client: PrismaClient, opts: { forbidden?: boolean } = {}) {
               if (wpProp === "findFirst") {
                 return (args: unknown) => {
                   calls.push(args);
-                  if (opts.forbidden) {
-                    throw new Error("this store must never be read");
+                  const select = (args as { select?: Record<string, unknown> })?.select ?? {};
+                  const keys = Object.keys(select);
+                  const isConnectedRunsRead = keys.length === 1 && keys[0] === "connectedRuns";
+                  if (isConnectedRunsRead) {
+                    connectedRunsCalls.push(args);
+                  } else {
+                    hydrateCalls.push(args);
+                    if (opts.forbidden) {
+                      throw new Error("this store must never be hydrated");
+                    }
                   }
                   return (wpTarget as any).findFirst(args);
                 };
@@ -95,6 +110,8 @@ function recording(client: PrismaClient, opts: { forbidden?: boolean } = {}) {
       },
     }) as unknown as PrismaReplicaClient,
     calls,
+    hydrateCalls,
+    connectedRunsCalls,
   };
 }
 
@@ -254,9 +271,12 @@ describe("WaitpointPresenter dual-DB read-through (hetero PG14 + PG17, no connec
       const result = await presenter.call(callArgs(ctx, seeded.friendlyId));
 
       expect(result?.id).toBe(seeded.friendlyId);
-      // New-first short-circuit: legacy never probed (the throwing handle proves it).
-      expect(newClient.calls.length).toBe(1);
-      expect(legacy.calls.length).toBe(0);
+      // New-first short-circuit: the HYDRATE answered from new and never fell through to a legacy
+      // hydrate (the throwing handle proves it). The connectedRuns cross-DB union still reads legacy
+      // legitimately -- that read is allowed and must NOT count as a hydrate.
+      expect(newClient.hydrateCalls.length).toBe(1);
+      expect(legacy.hydrateCalls.length).toBe(0);
+      expect(legacy.connectedRunsCalls.length).toBeGreaterThan(0);
     }
   );
 
@@ -285,8 +305,11 @@ describe("WaitpointPresenter dual-DB read-through (hetero PG14 + PG17, no connec
 
       expect(result?.id).toBe(seeded.friendlyId);
       expect(result?.tags).toEqual(["one"]);
-      // Exactly one read on the single client; the second handle is never touched.
-      expect(single.calls.length).toBe(1);
+      // Two reads on the single client, both on the one handle: the first findFirst hydrates the
+      // waitpoint, the second loads the `connectedRuns` relation (the implicit M2M has no queryable
+      // join delegate, so the ORM must traverse the relation with a second findFirst). The second
+      // handle is never touched -- passthrough is structural, the split branch never fires.
+      expect(single.calls.length).toBe(2);
       expect(second.calls.length).toBe(0);
     }
   );
diff --git a/apps/webapp/test/waitpointPresenter.splitConnectedRuns.test.ts b/apps/webapp/test/waitpointPresenter.splitConnectedRuns.test.ts
new file mode 100644
index 0000000000..ac321e210a
--- /dev/null
+++ b/apps/webapp/test/waitpointPresenter.splitConnectedRuns.test.ts
@@ -0,0 +1,208 @@
+// FLOW-level gap: a waitpoint's connected runs SPLIT across BOTH physical DBs at once (some legacy,
+// some new-resident) rather than the existing single-direction cross-DB cases in
+// waitpointPresenter.dedicatedConnectedRuns.readthrough.test.ts. Asserts #connectedRunFriendlyIds
+// unions friendlyIds gathered from BOTH stores in one read AND stays bounded to
+// CONNECTED_RUNS_DISPLAY_LIMIT even when the combined total exceeds it. Real two-physical-DB
+// topology (heteroRunOpsPostgresTest); never mocked beyond the same db.server/clickhouse/
+// NextRunListPresenter echo seams the sibling presenter tests use.
+import { describe, expect, vi } from "vitest";
+
+const legacyReplicaHolder = vi.hoisted(() => ({ client: undefined as any }));
+const newClientHolder = vi.hoisted(() => ({ client: undefined as any }));
+
+vi.mock("~/db.server", async () => {
+  const { Prisma } = await import("@trigger.dev/database");
+  const lazyProxy = (holder: { client: any }, label: string) =>
+    new Proxy(
+      {},
+      {
+        get(_t, prop) {
+          if (!holder.client) {
+            throw new Error(`${label} not set for this test`);
+          }
+          return holder.client[prop];
+        },
+      }
+    );
+  const replicaProxy = lazyProxy(legacyReplicaHolder, "legacyReplicaHolder.client");
+  return {
+    prisma: replicaProxy,
+    $replica: replicaProxy,
+    runOpsNewPrisma: lazyProxy(newClientHolder, "newClientHolder.client"),
+    runOpsNewReplica: lazyProxy(newClientHolder, "newClientHolder.client"),
+    runOpsLegacyPrisma: replicaProxy,
+    runOpsLegacyReplica: replicaProxy,
+    sqlDatabaseSchema: Prisma.sql([`public`]),
+    DATABASE_SCHEMA: "public",
+  };
+});
+
+vi.mock("~/services/clickhouse/clickhouseFactoryInstance.server", () => ({
+  clickhouseFactory: {
+    getClickhouseForOrganization: async () => ({}),
+  },
+}));
+
+// Echo the runId set back as runs so `result.connectedRuns` == the friendlyIds the presenter
+// gathered cross-DB (isolates the gather from the CH hydrate, as the sibling tests do).
+vi.mock("~/presenters/v3/NextRunListPresenter.server", () => ({
+  NextRunListPresenter: class {
+    // eslint-disable-next-line @typescript-eslint/no-unused-vars
+    constructor(..._args: unknown[]) {}
+    async call(_organizationId: string, _environmentId: string, opts: { runId?: string[] }) {
+      return {
+        runs: (opts.runId ?? []).map((friendlyId) => ({
+          friendlyId,
+          taskIdentifier: "echoed",
+        })),
+      };
+    }
+  },
+}));
+
+import { heteroRunOpsPostgresTest } from "@internal/testcontainers";
+import type { PrismaClient } from "@trigger.dev/database";
+import type { RunOpsPrismaClient } from "@internal/run-ops-database";
+import {
+  CONNECTED_RUNS_DISPLAY_LIMIT,
+  WaitpointPresenter,
+} from "~/presenters/v3/WaitpointPresenter.server";
+
+vi.setConfig({ testTimeout: 90_000 });
+
+type SeedContext = {
+  organizationId: string;
+  projectId: string;
+  environmentId: string;
+};
+
+async function seedParents(prisma: PrismaClient, slug: string): Promise<SeedContext> {
+  const organization = await prisma.organization.create({
+    data: { title: `org-${slug}`, slug: `org-${slug}` },
+  });
+  const project = await prisma.project.create({
+    data: {
+      name: `proj-${slug}`,
+      slug: `proj-${slug}`,
+      organizationId: organization.id,
+      externalRef: `proj-${slug}`,
+    },
+  });
+  const runtimeEnvironment = await prisma.runtimeEnvironment.create({
+    data: {
+      slug: `env-${slug}`,
+      type: "DEVELOPMENT",
+      projectId: project.id,
+      organizationId: organization.id,
+      apiKey: `tr_dev_${slug}`,
+      pkApiKey: `pk_dev_${slug}`,
+      shortcode: `sc-${slug}`,
+    },
+  });
+  return {
+    organizationId: organization.id,
+    projectId: project.id,
+    environmentId: runtimeEnvironment.id,
+  };
+}
+
+async function seedRun(
+  prisma: PrismaClient | RunOpsPrismaClient,
+  ctx: SeedContext,
+  friendlyId: string
+) {
+  return (prisma as PrismaClient).taskRun.create({
+    data: {
+      friendlyId,
+      taskIdentifier: "my-task",
+      status: "PENDING",
+      payload: JSON.stringify({ foo: friendlyId }),
+      payloadType: "application/json",
+      traceId: friendlyId,
+      spanId: friendlyId,
+      queue: "test",
+      runtimeEnvironmentId: ctx.environmentId,
+      projectId: ctx.projectId,
+      organizationId: ctx.organizationId,
+      environmentType: "DEVELOPMENT",
+      engine: "V2",
+    },
+  });
+}
+
+describe("WaitpointPresenter — connected runs SPLIT across both physical DBs", () => {
+  heteroRunOpsPostgresTest(
+    "unions connected-run friendlyIds from both stores and stays bounded to the display limit",
+    async ({ prisma14, prisma17 }) => {
+      const ctx = await seedParents(prisma14, "split");
+
+      // Waitpoint resident on LEGACY.
+      const waitpoint = await prisma14.waitpoint.create({
+        data: {
+          friendlyId: "waitpoint_split",
+          type: "MANUAL",
+          status: "COMPLETED",
+          idempotencyKey: "idem-waitpoint_split",
+          userProvidedIdempotencyKey: false,
+          outputType: "application/json",
+          outputIsError: false,
+          completedAt: new Date(),
+          tags: [],
+          projectId: ctx.projectId,
+          environmentId: ctx.environmentId,
+        },
+      });
+
+      // 2 connected runs resident + joined on NEW (below the limit on its own).
+      const NEW_RUN_FRIENDLY_IDS = ["run_split_new0", "run_split_new1"];
+      for (const friendlyId of NEW_RUN_FRIENDLY_IDS) {
+        const run = await seedRun(prisma17, ctx, friendlyId);
+        await prisma17.waitpointRunConnection.create({
+          data: { taskRunId: run.id, waitpointId: waitpoint.id },
+        });
+      }
+
+      // 6 connected runs resident + joined on LEGACY via the implicit M2M — more than enough, on its
+      // own, to push the combined total past CONNECTED_RUNS_DISPLAY_LIMIT (5).
+      const LEGACY_RUN_FRIENDLY_IDS = Array.from({ length: 6 }, (_, i) => `run_split_leg${i}`);
+      for (const friendlyId of LEGACY_RUN_FRIENDLY_IDS) {
+        const run = await seedRun(prisma14, ctx, friendlyId);
+        await prisma14.waitpoint.update({
+          where: { id: waitpoint.id },
+          data: { connectedRuns: { connect: [{ id: run.id }] } },
+        });
+      }
+
+      legacyReplicaHolder.client = prisma14;
+      newClientHolder.client = prisma17;
+
+      const presenter = new WaitpointPresenter(undefined, undefined, {
+        splitEnabled: true,
+        newClient: prisma17 as unknown as PrismaClient,
+        legacyReplica: prisma14,
+      });
+
+      const result = await presenter.call({
+        friendlyId: waitpoint.friendlyId,
+        environmentId: ctx.environmentId,
+        projectId: ctx.projectId,
+      });
+
+      const returnedIds = result?.connectedRuns.map((r) => r.friendlyId) ?? [];
+
+      // Bounded: the combined total across both DBs (8) must never surface more than the display
+      // limit, proving the fetch is capped globally, not just per-DB.
+      expect(returnedIds.length).toBeLessThanOrEqual(CONNECTED_RUNS_DISPLAY_LIMIT);
+      expect(returnedIds.length).toBeGreaterThan(0);
+
+      // BOTH stores contributed: at least one NEW-resident and one LEGACY-resident connected run
+      // friendlyId made it into the result. A single-store gather (the bug this guards against)
+      // would surface only one side.
+      const fromNew = returnedIds.filter((id) => NEW_RUN_FRIENDLY_IDS.includes(id));
+      const fromLegacy = returnedIds.filter((id) => LEGACY_RUN_FRIENDLY_IDS.includes(id));
+      expect(fromNew.length).toBeGreaterThan(0);
+      expect(fromLegacy.length).toBeGreaterThan(0);
+      expect(fromNew.length + fromLegacy.length).toBe(returnedIds.length);
+    }
+  );
+});
diff --git a/internal-packages/run-engine/src/engine/tests/legacyRunNewTokenResumeFlow.test.ts b/internal-packages/run-engine/src/engine/tests/legacyRunNewTokenResumeFlow.test.ts
new file mode 100644
index 0000000000..20f68f13d2
--- /dev/null
+++ b/internal-packages/run-engine/src/engine/tests/legacyRunNewTokenResumeFlow.test.ts
@@ -0,0 +1,302 @@
+// Completion -> resume FLOW test for the direction crossDbTokenBlock.test.ts's writer fix enables but
+// never itself exercises end-to-end: a LEGACY (cuid) run blocks on a standalone MANUAL token that is
+// NEW-resident (run-ops id) — e.g. the token was minted co-located with a run-ops sibling. This test
+// drives the real engine path (blockRunWithWaitpoint -> completeWaitpoint -> continueRunIfUnblocked)
+// across the two PHYSICAL DBs to prove the blocking edge is discovered and the run actually resumes,
+// not just that the edge write succeeds (that unit-level assertion already lives in
+// runOpsStore.crossDbTokenBlock.test.ts). Mirrors completeWaitpointReadResidency.test.ts's own
+// cross-DB case, but with the run/token residencies swapped. Real two-physical-DB topology; never
+// mocked.
+
+import {
+  heteroRunOpsPostgresTest,
+  network,
+  redisContainer,
+  redisOptions,
+} from "@internal/testcontainers";
+import { trace } from "@internal/tracing";
+import { PostgresRunStore, RoutingRunStore, type CreateRunInput } from "@internal/run-store";
+import { generateRunOpsId } from "@trigger.dev/core/v3/isomorphic";
+import type { PrismaClient } from "@trigger.dev/database";
+import type { RunOpsPrismaClient } from "@internal/run-ops-database";
+import { expect, vi } from "vitest";
+import { RunEngine } from "../index.js";
+
+const twoDbEngineTest = heteroRunOpsPostgresTest.extend<{
+  redisContainer: any;
+  redisOptions: any;
+}>({
+  network,
+  redisContainer,
+  redisOptions,
+});
+
+// 25-char cuid body (no v1 version marker at index 25) -> classifies LEGACY -> #legacy (prisma14).
+const CUID_25 = "c".repeat(25);
+
+function baseEngineOptions(redisOptions: any, prisma: any) {
+  return {
+    prisma,
+    worker: { redis: redisOptions, workers: 1, tasksPerWorker: 10, pollIntervalMs: 100 },
+    queue: {
+      redis: redisOptions,
+      masterQueueConsumersDisabled: true,
+      processWorkerQueueDebounceMs: 50,
+    },
+    runLock: { redis: redisOptions },
+    machines: {
+      defaultMachine: "small-1x" as const,
+      machines: {
+        "small-1x": { name: "small-1x" as const, cpu: 0.5, memory: 0.5, centsPerMs: 0.0001 },
+      },
+      baseCostInCents: 0.0001,
+    },
+    tracer: trace.getTracer("test", "0.0.0"),
+  };
+}
+
+async function seedControlPlaneEnv(prisma: PrismaClient, suffix: string) {
+  const organization = await prisma.organization.create({
+    data: { title: `Org ${suffix}`, slug: `org-${suffix}` },
+  });
+  const project = await prisma.project.create({
+    data: {
+      name: `Project ${suffix}`,
+      slug: `project-${suffix}`,
+      externalRef: `proj_${suffix}`,
+      organizationId: organization.id,
+    },
+  });
+  const environment = await prisma.runtimeEnvironment.create({
+    data: {
+      type: "PRODUCTION",
+      slug: `prod-${suffix}`,
+      projectId: project.id,
+      organizationId: organization.id,
+      apiKey: `tr_prod_${suffix}`,
+      pkApiKey: `pk_prod_${suffix}`,
+      shortcode: `short_${suffix}`,
+      maximumConcurrencyLimit: 10,
+    },
+  });
+  return { organization, project, environment };
+}
+
+function buildCreateRunInput(p: {
+  runId: string;
+  friendlyId: string;
+  organizationId: string;
+  projectId: string;
+  runtimeEnvironmentId: string;
+}): CreateRunInput {
+  return {
+    data: {
+      id: p.runId,
+      engine: "V2",
+      status: "EXECUTING",
+      friendlyId: p.friendlyId,
+      runtimeEnvironmentId: p.runtimeEnvironmentId,
+      environmentType: "PRODUCTION",
+      organizationId: p.organizationId,
+      projectId: p.projectId,
+      taskIdentifier: "parent-task",
+      payload: "{}",
+      payloadType: "application/json",
+      context: {},
+      traceContext: {},
+      traceId: `trace_${p.runId}`,
+      spanId: `span_${p.runId}`,
+      runTags: [],
+      queue: "task/parent-task",
+      isTest: false,
+      taskEventStore: "taskEvent",
+      depth: 0,
+      createdAt: new Date("2024-01-01T00:00:00.000Z"),
+    },
+    snapshot: {
+      engine: "V2",
+      executionStatus: "RUN_CREATED",
+      description: "Run was created",
+      runStatus: "PENDING",
+      environmentId: p.runtimeEnvironmentId,
+      environmentType: "PRODUCTION",
+      projectId: p.projectId,
+      organizationId: p.organizationId,
+    },
+  };
+}
+
+// Seed an EXECUTING LEGACY (cuid) parent run on #legacy (prisma14), plus a standalone MANUAL token
+// that is NEW-resident (run-ops id, minted co-located with some other run-ops sibling) on #new
+// (prisma17) ONLY — the token is never created on #legacy.
+async function seedExecutingLegacyParentAndNewToken(
+  prisma14: PrismaClient,
+  prisma17: RunOpsPrismaClient,
+  router: RoutingRunStore,
+  parentRunId: string,
+  waitpointId: string,
+  suffix: string
+) {
+  const env = await seedControlPlaneEnv(prisma14, suffix);
+
+  await router.createRun(
+    buildCreateRunInput({
+      runId: parentRunId,
+      friendlyId: `run_${suffix}_parent`,
+      organizationId: env.organization.id,
+      projectId: env.project.id,
+      runtimeEnvironmentId: env.environment.id,
+    })
+  );
+
+  const created = await router.findLatestExecutionSnapshot(parentRunId);
+  await router.createExecutionSnapshot(
+    {
+      run: { id: parentRunId, status: "EXECUTING", attemptNumber: 1 },
+      snapshot: { executionStatus: "EXECUTING", description: "parent executing" },
+      previousSnapshotId: created!.id,
+      environmentId: env.environment.id,
+      environmentType: "PRODUCTION",
+      projectId: env.project.id,
+      organizationId: env.organization.id,
+    },
+    prisma14
+  );
+
+  // Standalone MANUAL token lives on #new ONLY (run-ops id) — NOT on #legacy.
+  await prisma17.waitpoint.create({
+    data: {
+      id: waitpointId,
+      friendlyId: `wp_${suffix}`,
+      type: "MANUAL",
+      status: "PENDING",
+      idempotencyKey: `idem_${waitpointId}`,
+      userProvidedIdempotencyKey: false,
+      projectId: env.project.id,
+      environmentId: env.environment.id,
+    },
+  });
+
+  return env;
+}
+
+function makeRouter(prisma14: PrismaClient, prisma17: RunOpsPrismaClient) {
+  const newStore = new PostgresRunStore({
+    prisma: prisma17 as never,
+    readOnlyPrisma: prisma17 as never,
+    schemaVariant: "dedicated",
+  });
+  const legacyStore = new PostgresRunStore({
+    prisma: prisma14,
+    readOnlyPrisma: prisma14,
+    schemaVariant: "legacy",
+  });
+  return new RoutingRunStore({ new: newStore, legacy: legacyStore });
+}
+
+describe("RunEngine completion->resume flow — a LEGACY run blocked on a NEW-resident token resumes across the seam", () => {
+  twoDbEngineTest(
+    "completeWaitpoint on the NEW token finds the #legacy edge and unblocks the LEGACY run",
+    async ({ prisma14, prisma17, redisOptions }) => {
+      const router = makeRouter(prisma14 as unknown as PrismaClient, prisma17);
+
+      // The harness builds the schema with `prisma db push`, which re-creates the FKs that the
+      // run-ops split migrations drop in prod (see runOpsStore.crossDbTokenBlock.test.ts). Mirror
+      // those drops on this clone so the cross-DB edge write exercises real prod state.
+      await (prisma14 as unknown as PrismaClient).$executeRawUnsafe(
+        `ALTER TABLE "TaskRunWaitpoint" DROP CONSTRAINT IF EXISTS "TaskRunWaitpoint_waitpointId_fkey"`
+      );
+      await (prisma14 as unknown as PrismaClient).$executeRawUnsafe(
+        `ALTER TABLE "_WaitpointRunConnections" DROP CONSTRAINT IF EXISTS "_WaitpointRunConnections_B_fkey"`
+      );
+      // continueRunIfUnblocked's resume snapshot connects the now-COMPLETED (NEW-resident) token via
+      // _completedWaitpoints (migration 20260705230000 drops this FK in prod; see
+      // runOpsStore.crossDbCompletedWaitpoint.test.ts).
+      await (prisma14 as unknown as PrismaClient).$executeRawUnsafe(
+        `ALTER TABLE "_completedWaitpoints" DROP CONSTRAINT IF EXISTS "_completedWaitpoints_B_fkey"`
+      );
+
+      const engine = new RunEngine({
+        store: router,
+        ...baseEngineOptions(redisOptions, prisma14),
+      });
+
+      try {
+        const parentRunId = `run_${CUID_25}`; // LEGACY run -> #legacy
+        const tokenId = `waitpoint_${generateRunOpsId()}`; // NEW-resident standalone token -> #new
+        const env = await seedExecutingLegacyParentAndNewToken(
+          prisma14 as unknown as PrismaClient,
+          prisma17,
+          router,
+          parentRunId,
+          tokenId,
+          "xdbresume"
+        );
+
+        // Block the LEGACY run on the NEW token. The edge must land on #legacy (the run's own DB,
+        // FK-free now that the migration-dropped constraints are mirrored above).
+        await engine.blockRunWithWaitpoint({
+          runId: parentRunId,
+          waitpoints: tokenId,
+          projectId: env.project.id,
+          organizationId: env.organization.id,
+          tx: prisma14 as unknown as PrismaClient,
+        });
+
+        expect(
+          await (prisma14 as unknown as PrismaClient).taskRunWaitpoint.count({
+            where: { taskRunId: parentRunId },
+          })
+        ).toBe(1);
+        expect(await prisma17.taskRunWaitpoint.count({ where: { taskRunId: parentRunId } })).toBe(
+          0
+        );
+
+        const blocked = await engine.getRunExecutionData({ runId: parentRunId });
+        expect(blocked?.snapshot.executionStatus).toBe("EXECUTING_WITH_WAITPOINTS");
+
+        const enqueueSpy = vi.spyOn((engine as any).worker, "enqueue");
+
+        // Complete the NEW token via the engine path. forWaitpointCompletion resolves #new (run-ops
+        // id, no pins); completeWaitpoint marks it COMPLETED there, then fans the waitpointId edge
+        // read across BOTH DBs (findManyTaskRunWaitpoints) to discover the #legacy-resident edge.
+        const completed = await engine.completeWaitpoint({
+          id: tokenId,
+          output: { value: '{"resumed":"legacy-run-new-token"}', isError: false },
+        });
+        expect(completed.status).toBe("COMPLETED");
+
+        // Token COMPLETED on #new only.
+        expect((await prisma17.waitpoint.findFirst({ where: { id: tokenId } }))?.status).toBe(
+          "COMPLETED"
+        );
+        expect(
+          await (prisma14 as unknown as PrismaClient).waitpoint.findFirst({
+            where: { id: tokenId },
+          })
+        ).toBeNull();
+
+        // The fan-out found the #legacy edge and enqueued the unblock for the LEGACY run.
+        const continueEnqueued = enqueueSpy.mock.calls.some(
+          ([arg]) =>
+            (arg as any)?.job === "continueRunIfUnblocked" &&
+            (arg as any)?.payload?.runId === parentRunId
+        );
+        expect(continueEnqueued).toBe(true);
+
+        // Driving the unblock body re-resolves the NEW token's COMPLETED status across the seam
+        // (continueRunIfUnblocked's blockingWaitpoints read rehydrates `waitpoint` cross-DB) and
+        // actually resumes the LEGACY run — the higher-level outcome, not just the edge write.
+        const result = await (engine as any).waitpointSystem.continueRunIfUnblocked({
+          runId: parentRunId,
+        });
+        expect(result.status).toBe("unblocked");
+
+        const after = await engine.getRunExecutionData({ runId: parentRunId });
+        expect(after?.snapshot.executionStatus).not.toBe("EXECUTING_WITH_WAITPOINTS");
+      } finally {
+        await engine.quit();
+      }
+    }
+  );
+});
diff --git a/internal-packages/run-store/src/PostgresRunStore.connectedRunsBounded.test.ts b/internal-packages/run-store/src/PostgresRunStore.connectedRunsBounded.test.ts
new file mode 100644
index 0000000000..e20ad22805
--- /dev/null
+++ b/internal-packages/run-store/src/PostgresRunStore.connectedRunsBounded.test.ts
@@ -0,0 +1,286 @@
+// RED→GREEN for bounding the connected-runs read path so it can never emit an unbounded id list.
+//
+// Mirrors the fix already shipped in `apps/webapp/app/presenters/v3/WaitpointPresenter.server.ts`
+// `#connectedRunIdsOn`: existence-JOIN to TaskRun (so a dangling connection row can never occupy a
+// LIMIT slot ahead of a real run), then LIMIT to `CONNECTED_RUNS_LIMIT` on BOTH schema branches.
+//
+// `PostgresRunStore.findWaitpointConnectedRunIds` currently has neither: the dedicated branch does
+// a bare `waitpointRunConnection.findMany` (no LIMIT, no existence check) and the legacy branch does
+// a bare `SELECT "A" FROM "_WaitpointRunConnections"` (same). `RoutingRunStore.findWaitpointConnectedRunIds`
+// unions the two stores' results with no final cap, so even if each store were individually bounded
+// the cross-DB union would not be.
+
+import { heteroRunOpsPostgresTest } from "@internal/testcontainers";
+import { describe, expect } from "vitest";
+import { CONNECTED_RUNS_LIMIT, PostgresRunStore } from "./PostgresRunStore.js";
+import { RoutingRunStore } from "./runOpsStore.js";
+
+function seedEnvironmentDedicated(suffix: string) {
+  return {
+    organization: { id: `org_${suffix}` },
+    project: { id: `proj_${suffix}` },
+    environment: { id: `env_${suffix}` },
+  };
+}
+
+async function seedEnvironmentLegacy(prisma: any, suffix: string) {
+  const organization = await prisma.organization.create({
+    data: { title: `Org ${suffix}`, slug: `org-${suffix}` },
+  });
+  const project = await prisma.project.create({
+    data: {
+      name: `Project ${suffix}`,
+      slug: `project-${suffix}`,
+      externalRef: `proj_${suffix}`,
+      organizationId: organization.id,
+    },
+  });
+  const environment = await prisma.runtimeEnvironment.create({
+    data: {
+      type: "DEVELOPMENT",
+      slug: "dev",
+      projectId: project.id,
+      organizationId: organization.id,
+      apiKey: `tr_dev_${suffix}`,
+      pkApiKey: `pk_dev_${suffix}`,
+      shortcode: `short_${suffix}`,
+    },
+  });
+  return { organization, project, environment };
+}
+
+function taskRunData(opts: {
+  id: string;
+  friendlyId: string;
+  organizationId: string;
+  projectId: string;
+  runtimeEnvironmentId: string;
+}) {
+  return {
+    id: opts.id,
+    engine: "V2" as const,
+    status: "PENDING" as const,
+    friendlyId: opts.friendlyId,
+    runtimeEnvironmentId: opts.runtimeEnvironmentId,
+    environmentType: "DEVELOPMENT" as const,
+    organizationId: opts.organizationId,
+    projectId: opts.projectId,
+    taskIdentifier: "my-task",
+    payload: "{}",
+    payloadType: "application/json",
+    traceContext: {},
+    traceId: `trace_${opts.id}`,
+    spanId: `span_${opts.id}`,
+    queue: "task/my-task",
+    isTest: false,
+    taskEventStore: "taskEvent",
+    depth: 0,
+  };
+}
+
+describe("PostgresRunStore.findWaitpointConnectedRunIds — bounded via existence-JOIN + LIMIT", () => {
+  heteroRunOpsPostgresTest(
+    "dedicated schema: caps at CONNECTED_RUNS_LIMIT and never returns a dangling (run-less) connection",
+    async ({ prisma17 }) => {
+      const store = new PostgresRunStore({
+        prisma: prisma17 as never,
+        readOnlyPrisma: prisma17 as never,
+        schemaVariant: "dedicated",
+      });
+
+      const newEnv = seedEnvironmentDedicated("bound_new");
+      const waitpointId = "waitpoint_bound_new";
+      await prisma17.waitpoint.create({
+        data: {
+          id: waitpointId,
+          friendlyId: "wp_bound_new",
+          type: "MANUAL",
+          status: "PENDING",
+          idempotencyKey: `idem_${waitpointId}`,
+          userProvidedIdempotencyKey: false,
+          projectId: newEnv.project.id,
+          environmentId: newEnv.environment.id,
+        },
+      });
+
+      // Dangling connections FIRST: taskRunId points at runs that were NEVER created. Legal on the
+      // dedicated schema — `WaitpointRunConnection.taskRunId` is a scalar, no FK (see schema.prisma).
+      const danglingRunIds = Array.from({ length: 20 }, (_, i) => `run_dangling_${i}`);
+      for (const runId of danglingRunIds) {
+        await store.blockRunWithWaitpointEdges({
+          runId,
+          waitpointIds: [waitpointId],
+          projectId: newEnv.project.id,
+        });
+      }
+
+      // A few REAL connected runs, inserted AFTER the dangling ones.
+      const realRunIds = ["run_real_0", "run_real_1", "run_real_2"];
+      for (const [i, id] of realRunIds.entries()) {
+        await prisma17.taskRun.create({
+          data: taskRunData({
+            id,
+            friendlyId: `run_bound_new_${i}`,
+            organizationId: newEnv.organization.id,
+            projectId: newEnv.project.id,
+            runtimeEnvironmentId: newEnv.environment.id,
+          }),
+        });
+        await store.blockRunWithWaitpointEdges({
+          runId: id,
+          waitpointIds: [waitpointId],
+          projectId: newEnv.project.id,
+        });
+      }
+
+      const result = await store.findWaitpointConnectedRunIds(waitpointId);
+
+      // Bounded.
+      expect(result.length).toBeLessThanOrEqual(CONNECTED_RUNS_LIMIT);
+      // Never a dangling id — every returned id must be one of the REAL runs.
+      for (const id of result) {
+        expect(realRunIds).toContain(id);
+      }
+      // Not starved out: all 3 real runs (well under the limit) must be present.
+      for (const id of realRunIds) {
+        expect(result).toContain(id);
+      }
+    }
+  );
+
+  heteroRunOpsPostgresTest(
+    "legacy schema: caps at CONNECTED_RUNS_LIMIT instead of returning every connected run",
+    async ({ prisma14 }) => {
+      const store = new PostgresRunStore({
+        prisma: prisma14 as never,
+        readOnlyPrisma: prisma14 as never,
+        schemaVariant: "legacy",
+      });
+
+      const legEnv = await seedEnvironmentLegacy(prisma14, "bound_leg");
+      const waitpointId = "waitpoint_bound_leg";
+      await prisma14.waitpoint.create({
+        data: {
+          id: waitpointId,
+          friendlyId: "wp_bound_leg",
+          type: "MANUAL",
+          status: "PENDING",
+          idempotencyKey: `idem_${waitpointId}`,
+          userProvidedIdempotencyKey: false,
+          projectId: legEnv.project.id,
+          environmentId: legEnv.environment.id,
+        },
+      });
+
+      // More real connected runs than CONNECTED_RUNS_LIMIT — the legacy `_WaitpointRunConnections`
+      // table still enforces an FK from "A" to TaskRun, so every row here is a real run.
+      const realRunIds = Array.from({ length: CONNECTED_RUNS_LIMIT + 3 }, (_, i) => `run_leg_${i}`);
+      for (const [i, id] of realRunIds.entries()) {
+        await prisma14.taskRun.create({
+          data: taskRunData({
+            id,
+            friendlyId: `run_bound_leg_${i}`,
+            organizationId: legEnv.organization.id,
+            projectId: legEnv.project.id,
+            runtimeEnvironmentId: legEnv.environment.id,
+          }),
+        });
+        await store.blockRunWithWaitpointEdges({
+          runId: id,
+          waitpointIds: [waitpointId],
+          projectId: legEnv.project.id,
+        });
+      }
+
+      const result = await store.findWaitpointConnectedRunIds(waitpointId);
+
+      expect(result.length).toBeLessThanOrEqual(CONNECTED_RUNS_LIMIT);
+    }
+  );
+});
+
+describe("RoutingRunStore.findWaitpointConnectedRunIds — the cross-DB union is also bounded", () => {
+  heteroRunOpsPostgresTest(
+    "slices the merged NEW+LEGACY result to CONNECTED_RUNS_LIMIT",
+    async ({ prisma14, prisma17 }) => {
+      const legacyStore = new PostgresRunStore({
+        prisma: prisma14 as never,
+        readOnlyPrisma: prisma14 as never,
+        schemaVariant: "legacy",
+      });
+      const newStore = new PostgresRunStore({
+        prisma: prisma17 as never,
+        readOnlyPrisma: prisma17 as never,
+        schemaVariant: "dedicated",
+      });
+      const router = new RoutingRunStore({ new: newStore, legacy: legacyStore });
+
+      const legEnv = await seedEnvironmentLegacy(prisma14, "bound_union_leg");
+      const newEnv = seedEnvironmentDedicated("bound_union_new");
+      const waitpointId = "waitpoint_bound_union";
+      // The legacy `TaskRunWaitpoint.waitpointId` FK is still live in this test DB (built via
+      // `prisma db push` from schema.prisma, which still declares the relation even though a later
+      // migration drops the constraint in real deployments) — the legacy leg needs a real row here.
+      await prisma14.waitpoint.create({
+        data: {
+          id: waitpointId,
+          friendlyId: "wp_bound_union",
+          type: "MANUAL",
+          status: "PENDING",
+          idempotencyKey: `idem_${waitpointId}`,
+          userProvidedIdempotencyKey: false,
+          projectId: legEnv.project.id,
+          environmentId: legEnv.environment.id,
+        },
+      });
+
+      // Each store individually caps at CONNECTED_RUNS_LIMIT, but a distinct set of runs on EACH side
+      // means the union of the two capped results can still exceed the limit without a final slice.
+      const legacyRunIds = Array.from(
+        { length: CONNECTED_RUNS_LIMIT },
+        (_, i) => `run_union_leg_${i}`
+      );
+      for (const [i, id] of legacyRunIds.entries()) {
+        await prisma14.taskRun.create({
+          data: taskRunData({
+            id,
+            friendlyId: `run_union_leg_${i}`,
+            organizationId: legEnv.organization.id,
+            projectId: legEnv.project.id,
+            runtimeEnvironmentId: legEnv.environment.id,
+          }),
+        });
+        await legacyStore.blockRunWithWaitpointEdges({
+          runId: id,
+          waitpointIds: [waitpointId],
+          projectId: legEnv.project.id,
+        });
+      }
+
+      const newRunIds = Array.from(
+        { length: CONNECTED_RUNS_LIMIT },
+        (_, i) => `run_union_new_${i}`
+      );
+      for (const [i, id] of newRunIds.entries()) {
+        await prisma17.taskRun.create({
+          data: taskRunData({
+            id,
+            friendlyId: `run_union_new_${i}`,
+            organizationId: newEnv.organization.id,
+            projectId: newEnv.project.id,
+            runtimeEnvironmentId: newEnv.environment.id,
+          }),
+        });
+        await newStore.blockRunWithWaitpointEdges({
+          runId: id,
+          waitpointIds: [waitpointId],
+          projectId: newEnv.project.id,
+        });
+      }
+
+      const result = await router.findWaitpointConnectedRunIds(waitpointId);
+
+      expect(result.length).toBeLessThanOrEqual(CONNECTED_RUNS_LIMIT);
+    }
+  );
+});
diff --git a/internal-packages/run-store/src/PostgresRunStore.connectedRunsIncludeBounded.test.ts b/internal-packages/run-store/src/PostgresRunStore.connectedRunsIncludeBounded.test.ts
new file mode 100644
index 0000000000..a2ce43103c
--- /dev/null
+++ b/internal-packages/run-store/src/PostgresRunStore.connectedRunsIncludeBounded.test.ts
@@ -0,0 +1,130 @@
+// RED→GREEN for bounding the DISPLAY `connectedRuns` RELATION hydration (findWaitpoint /
+// findManyWaitpoints with `include`/`select: { connectedRuns }`), NOT the id-list helper
+// `findWaitpointConnectedRunIds` (covered separately in connectedRunsBounded.test.ts).
+//
+// The dedicated-schema hydrator `hydrateConnectedRuns` goes through the generic
+// `batchHydrateJoinRelation`, which fetched EVERY WaitpointRunConnection link with no per-parent
+// cap — so a heavily-fanned-in waitpoint hydrated an unbounded connectedRuns list, bypassing the
+// CONNECTED_RUNS_LIMIT the presenter/`findWaitpointConnectedRunIds` already enforce.
+//
+// The fix bounds it per parent via a window function + existence-JOIN to TaskRun, mirroring the
+// bounded helper: a dangling connection row never occupies a LIMIT slot, and the returned relation
+// is capped at CONNECTED_RUNS_LIMIT.
+
+import { heteroRunOpsPostgresTest } from "@internal/testcontainers";
+import { describe, expect } from "vitest";
+import { CONNECTED_RUNS_LIMIT, PostgresRunStore } from "./PostgresRunStore.js";
+
+function seedEnvironmentDedicated(suffix: string) {
+  return {
+    organization: { id: `org_${suffix}` },
+    project: { id: `proj_${suffix}` },
+    environment: { id: `env_${suffix}` },
+  };
+}
+
+function taskRunData(opts: {
+  id: string;
+  friendlyId: string;
+  organizationId: string;
+  projectId: string;
+  runtimeEnvironmentId: string;
+}) {
+  return {
+    id: opts.id,
+    engine: "V2" as const,
+    status: "PENDING" as const,
+    friendlyId: opts.friendlyId,
+    runtimeEnvironmentId: opts.runtimeEnvironmentId,
+    environmentType: "DEVELOPMENT" as const,
+    organizationId: opts.organizationId,
+    projectId: opts.projectId,
+    taskIdentifier: "my-task",
+    payload: "{}",
+    payloadType: "application/json",
+    traceContext: {},
+    traceId: `trace_${opts.id}`,
+    spanId: `span_${opts.id}`,
+    queue: "task/my-task",
+    isTest: false,
+    taskEventStore: "taskEvent",
+    depth: 0,
+  };
+}
+
+describe("PostgresRunStore.findWaitpoint — connectedRuns relation is bounded", () => {
+  heteroRunOpsPostgresTest(
+    "dedicated schema: include connectedRuns caps at CONNECTED_RUNS_LIMIT and skips dangling connections",
+    async ({ prisma17 }) => {
+      const store = new PostgresRunStore({
+        prisma: prisma17 as never,
+        readOnlyPrisma: prisma17 as never,
+        schemaVariant: "dedicated",
+      });
+
+      const env = seedEnvironmentDedicated("cr_incl_new");
+      const waitpointId = "waitpoint_cr_incl_new";
+      await prisma17.waitpoint.create({
+        data: {
+          id: waitpointId,
+          friendlyId: "wp_cr_incl_new",
+          type: "MANUAL",
+          status: "PENDING",
+          idempotencyKey: `idem_${waitpointId}`,
+          userProvidedIdempotencyKey: false,
+          projectId: env.project.id,
+          environmentId: env.environment.id,
+        },
+      });
+
+      // Dangling connections (taskRunId points at runs that were never created). Legal on the
+      // dedicated schema — WaitpointRunConnection.taskRunId is a scalar with no FK.
+      const danglingRunIds = Array.from({ length: 20 }, (_, i) => `run_cr_dangling_${i}`);
+      for (const runId of danglingRunIds) {
+        await store.blockRunWithWaitpointEdges({
+          runId,
+          waitpointIds: [waitpointId],
+          projectId: env.project.id,
+        });
+      }
+
+      // More REAL connected runs than the limit.
+      const realRunIds = Array.from(
+        { length: CONNECTED_RUNS_LIMIT + 3 },
+        (_, i) => `run_cr_real_${i}`
+      );
+      for (const [i, id] of realRunIds.entries()) {
+        await prisma17.taskRun.create({
+          data: taskRunData({
+            id,
+            friendlyId: `run_cr_incl_new_${i}`,
+            organizationId: env.organization.id,
+            projectId: env.project.id,
+            runtimeEnvironmentId: env.environment.id,
+          }),
+        });
+        await store.blockRunWithWaitpointEdges({
+          runId: id,
+          waitpointIds: [waitpointId],
+          projectId: env.project.id,
+        });
+      }
+
+      const waitpoint = (await store.findWaitpoint({
+        where: { id: waitpointId },
+        include: { connectedRuns: true },
+      })) as unknown as { connectedRuns: { id: string }[] } | null;
+
+      expect(waitpoint).not.toBeNull();
+      const connectedRuns = waitpoint!.connectedRuns;
+
+      // Bounded to exactly the cap (fixture connects more real runs than the limit).
+      expect(connectedRuns).toHaveLength(CONNECTED_RUNS_LIMIT);
+      // Never a dangling id — every returned run must be a REAL run.
+      for (const run of connectedRuns) {
+        expect(realRunIds).toContain(run.id);
+        expect(danglingRunIds).not.toContain(run.id);
+      }
+    }
+  );
+});
diff --git a/internal-packages/run-store/src/PostgresRunStore.findRunsByIds.test.ts b/internal-packages/run-store/src/PostgresRunStore.findRunsByIds.test.ts
new file mode 100644
index 0000000000..10e9aa8086
--- /dev/null
+++ b/internal-packages/run-store/src/PostgresRunStore.findRunsByIds.test.ts
@@ -0,0 +1,175 @@
+// RED→GREEN: `findRunsByIds` is the grouped replacement for `Promise.all(ids.map(id =>
+// findRun(id)))` — it must issue ONE `findMany` for the whole id batch, never a `findFirst`
+// per id. `postgresTest` is a REAL PrismaClient over the standard (non-dedicated) schema. The
+// counting proxy wraps its `taskRun` delegate to tally `findFirst`/`findMany` calls while
+// delegating every call to the real client — the DB still runs the query; this is
+// instrumentation, not a mock.
+
+import { postgresTest } from "@internal/testcontainers";
+import type { PrismaClient } from "@trigger.dev/database";
+import { describe, expect } from "vitest";
+import { PostgresRunStore } from "./PostgresRunStore.js";
+import type { CreateRunInput } from "./types.js";
+
+type CallCounts = { findMany: number; findFirst: number };
+
+// Wraps the named delegates on a REAL client to tally `findMany`/`findFirst` calls PER delegate,
+// delegating every call unchanged to the real client (the DB still runs the query).
+function countingClient(
+  real: PrismaClient,
+  delegateNames: string[]
+): { client: PrismaClient; counts: Record<string, CallCounts> } {
+  const counts: Record<string, CallCounts> = {};
+  for (const name of delegateNames) {
+    counts[name] = { findMany: 0, findFirst: 0 };
+  }
+  const wrapped = new Map(
+    delegateNames.map((name) => [
+      name,
+      new Proxy((real as any)[name], {
+        get(target, prop) {
+          if (prop === "findMany" || prop === "findFirst") {
+            counts[name][prop as "findMany" | "findFirst"]++;
+          }
+          return (target as any)[prop];
+        },
+      }),
+    ])
+  );
+  const client = new Proxy(real, {
+    get(target, prop) {
+      if (typeof prop === "string" && wrapped.has(prop)) {
+        return wrapped.get(prop);
+      }
+      return (target as any)[prop];
+    },
+  }) as PrismaClient;
+  return { client, counts };
+}
+
+async function seedEnvironment(prisma: PrismaClient) {
+  const organization = await prisma.organization.create({
+    data: {
+      title: "Test Organization",
+      slug: "test-organization-findrunsbyids",
+    },
+  });
+
+  const project = await prisma.project.create({
+    data: {
+      name: "Test Project",
+      slug: "test-project-findrunsbyids",
+      externalRef: "proj_findrunsbyids",
+      organizationId: organization.id,
+    },
+  });
+
+  const environment = await prisma.runtimeEnvironment.create({
+    data: {
+      type: "DEVELOPMENT",
+      slug: "dev",
+      projectId: project.id,
+      organizationId: organization.id,
+      apiKey: "tr_dev_apikey_findrunsbyids",
+      pkApiKey: "pk_dev_apikey_findrunsbyids",
+      shortcode: "short_code_findrunsbyids",
+    },
+  });
+
+  return { organization, project, environment };
+}
+
+function buildCreateRunInput(params: {
+  runId: string;
+  friendlyId: string;
+  organizationId: string;
+  projectId: string;
+  runtimeEnvironmentId: string;
+}): CreateRunInput {
+  return {
+    data: {
+      id: params.runId,
+      engine: "V2",
+      status: "PENDING",
+      friendlyId: params.friendlyId,
+      runtimeEnvironmentId: params.runtimeEnvironmentId,
+      environmentType: "DEVELOPMENT",
+      organizationId: params.organizationId,
+      projectId: params.projectId,
+      taskIdentifier: "my-task",
+      payload: "{}",
+      payloadType: "application/json",
+      traceContext: {},
+      traceId: `trace_${params.runId}`,
+      spanId: `span_${params.runId}`,
+      queue: "task/my-task",
+      isTest: false,
+      taskEventStore: "taskEvent",
+      depth: 0,
+    },
+    snapshot: {
+      engine: "V2",
+      executionStatus: "RUN_CREATED",
+      description: "Run was created",
+      runStatus: "PENDING",
+      environmentId: params.runtimeEnvironmentId,
+      environmentType: "DEVELOPMENT",
+      projectId: params.projectId,
+      organizationId: params.organizationId,
+    },
+  };
+}
+
+describe("PostgresRunStore.findRunsByIds", () => {
+  postgresTest(
+    "resolves N ids with ONE grouped findMany, never a findFirst per id",
+    async ({ prisma }) => {
+      const { organization, project, environment } = await seedEnvironment(prisma);
+
+      const seedStore = new PostgresRunStore({ prisma, readOnlyPrisma: prisma });
+
+      const runId1 = "run_findbyids_1";
+      const runId2 = "run_findbyids_2";
+      await seedStore.createRun(
+        buildCreateRunInput({
+          runId: runId1,
+          friendlyId: "run_findbyids_1_friendly",
+          organizationId: organization.id,
+          projectId: project.id,
+          runtimeEnvironmentId: environment.id,
+        })
+      );
+      await seedStore.createRun(
+        buildCreateRunInput({
+          runId: runId2,
+          friendlyId: "run_findbyids_2_friendly",
+          organizationId: organization.id,
+          projectId: project.id,
+          runtimeEnvironmentId: environment.id,
+        })
+      );
+
+      const counting = countingClient(prisma, ["taskRun"]);
+      const readStore = new PostgresRunStore({ prisma, readOnlyPrisma: counting.client });
+
+      const byId = await readStore.findRunsByIds([runId1, runId2], {
+        select: { friendlyId: true, status: true },
+      });
+
+      expect(byId.size).toBe(2);
+      expect(byId.get(runId1)?.friendlyId).toBe("run_findbyids_1_friendly");
+      expect(byId.get(runId1)?.status).toBe("PENDING");
+      expect(byId.get(runId2)?.friendlyId).toBe("run_findbyids_2_friendly");
+      expect(byId.get(runId2)?.status).toBe("PENDING");
+
+      // The select omitted `id`; the id we force-inject for keying must not leak into the value
+      // (it would otherwise violate the declared payload type and expose an unrequested id).
+      expect("id" in (byId.get(runId1) as object)).toBe(false);
+      expect("id" in (byId.get(runId2) as object)).toBe(false);
+
+      // GROUPED: one findMany for the WHOLE batch, never one findFirst per id.
+      expect(counting.counts.taskRun.findMany).toBe(1);
+      expect(counting.counts.taskRun.findFirst).toBe(0);
+    }
+  );
+});
diff --git a/internal-packages/run-store/src/PostgresRunStore.groupedRelations.test.ts b/internal-packages/run-store/src/PostgresRunStore.groupedRelations.test.ts
new file mode 100644
index 0000000000..6323ca4858
--- /dev/null
+++ b/internal-packages/run-store/src/PostgresRunStore.groupedRelations.test.ts
@@ -0,0 +1,239 @@
+// RED→GREEN: the dedicated-schema relation hydrators (`hydrateBlockingTaskRuns` /
+// `#hydrateDedicatedRelations`) resolve a relation PER PARENT ROW, so for N parents each requesting
+// the same relation, the store issues N round trips (a `findFirst`/`findMany` per row) instead of one
+// grouped query for the whole batch. `heteroRunOpsPostgresTest.prisma17` is a REAL RunOpsPrismaClient
+// over the dedicated subset schema. The counting proxy wraps its `taskRun` delegate to tally
+// `findFirst`/`findMany` calls while delegating every call to the real client — the DB still runs the
+// query; this is instrumentation, not a mock.
+
+import { heteroRunOpsPostgresTest } from "@internal/testcontainers";
+import type { RunOpsPrismaClient } from "@internal/run-ops-database";
+import { describe, expect } from "vitest";
+import { PostgresRunStore } from "./PostgresRunStore.js";
+import type { CreateRunInput } from "./types.js";
+
+type CallCounts = { findMany: number; findFirst: number };
+
+// Wraps the named delegates on a REAL client to tally `findMany`/`findFirst` calls PER delegate,
+// delegating every call unchanged to the real client (the DB still runs the query).
+function countingClient(
+  real: RunOpsPrismaClient,
+  delegateNames: string[]
+): { client: RunOpsPrismaClient; counts: Record<string, CallCounts>; queryRaw: { count: number } } {
+  const counts: Record<string, CallCounts> = {};
+  for (const name of delegateNames) {
+    counts[name] = { findMany: 0, findFirst: 0 };
+  }
+  const queryRaw = { count: 0 };
+  const wrapped = new Map(
+    delegateNames.map((name) => [
+      name,
+      new Proxy((real as any)[name], {
+        get(target, prop) {
+          if (prop === "findMany" || prop === "findFirst") {
+            counts[name][prop as "findMany" | "findFirst"]++;
+          }
+          return (target as any)[prop];
+        },
+      }),
+    ])
+  );
+  const client = new Proxy(real, {
+    get(target, prop) {
+      if (typeof prop === "string" && wrapped.has(prop)) {
+        return wrapped.get(prop);
+      }
+      // Tally the grouped raw query the bounded connectedRuns hydrator issues, delegating unchanged.
+      if (prop === "$queryRaw") {
+        return (...args: unknown[]) => {
+          queryRaw.count++;
+          return (target as any).$queryRaw(...args);
+        };
+      }
+      return (target as any)[prop];
+    },
+  }) as RunOpsPrismaClient;
+  return { client, counts, queryRaw };
+}
+
+function seedEnvironmentDedicated(suffix: string) {
+  return {
+    organization: { id: `org_${suffix}` },
+    project: { id: `proj_${suffix}` },
+    environment: { id: `env_${suffix}` },
+  };
+}
+
+function buildCreateRunInput(params: {
+  runId: string;
+  friendlyId: string;
+  organizationId: string;
+  projectId: string;
+  runtimeEnvironmentId: string;
+}): CreateRunInput {
+  return {
+    data: {
+      id: params.runId,
+      engine: "V2",
+      status: "PENDING",
+      friendlyId: params.friendlyId,
+      runtimeEnvironmentId: params.runtimeEnvironmentId,
+      environmentType: "DEVELOPMENT",
+      organizationId: params.organizationId,
+      projectId: params.projectId,
+      taskIdentifier: "my-task",
+      payload: '{"hello":"world"}',
+      payloadType: "application/json",
+      traceContext: { trace: "ctx" },
+      traceId: `trace_${params.runId}`,
+      spanId: `span_${params.runId}`,
+      runTags: [],
+      queue: "task/my-task",
+      isTest: false,
+      taskEventStore: "taskEvent",
+      depth: 0,
+      createdAt: new Date("2024-01-01T00:00:00.000Z"),
+    },
+    snapshot: {
+      engine: "V2",
+      executionStatus: "RUN_CREATED",
+      description: "Run was created",
+      runStatus: "PENDING",
+      environmentId: params.runtimeEnvironmentId,
+      environmentType: "DEVELOPMENT",
+      projectId: params.projectId,
+      organizationId: params.organizationId,
+    },
+  };
+}
+
+function makeStore(prisma: RunOpsPrismaClient) {
+  return new PostgresRunStore({
+    prisma: prisma as never,
+    readOnlyPrisma: prisma as never,
+    schemaVariant: "dedicated",
+  });
+}
+
+describe("PostgresRunStore dedicated relation hydrators — grouped batch reads", () => {
+  heteroRunOpsPostgresTest(
+    "hydrateBlockingTaskRuns resolves N edges' `taskRun` with ONE grouped findMany, not N findFirst",
+    async ({ prisma17 }) => {
+      const seedStore = makeStore(prisma17);
+      const env = seedEnvironmentDedicated("hbt");
+      const waitpointId = "wp_hbt_shared";
+      await prisma17.waitpoint.create({
+        data: {
+          id: waitpointId,
+          friendlyId: "wp_hbt_friendly",
+          type: "MANUAL",
+          status: "PENDING",
+          idempotencyKey: `idem_${waitpointId}`,
+          userProvidedIdempotencyKey: false,
+          projectId: env.project.id,
+          environmentId: env.environment.id,
+        },
+      });
+
+      const runIds = ["run_hbt_1", "run_hbt_2", "run_hbt_3"];
+      for (const runId of runIds) {
+        await seedStore.createRun(
+          buildCreateRunInput({
+            runId,
+            friendlyId: `${runId}_friendly`,
+            organizationId: env.organization.id,
+            projectId: env.project.id,
+            runtimeEnvironmentId: env.environment.id,
+          })
+        );
+        await seedStore.blockRunWithWaitpointEdges({
+          runId,
+          waitpointIds: [waitpointId],
+          projectId: env.project.id,
+        });
+      }
+
+      const counting = countingClient(prisma17, ["taskRun"]);
+      const readStore = makeStore(counting.client);
+
+      const waitpoint = (await readStore.findWaitpoint({
+        where: { id: waitpointId },
+        include: {
+          blockingTaskRuns: { select: { taskRun: { select: { id: true, friendlyId: true } } } },
+        },
+      })) as { blockingTaskRuns: { taskRun: { id: string; friendlyId: string } | null }[] } | null;
+
+      const blocking = waitpoint?.blockingTaskRuns ?? [];
+      expect(blocking).toHaveLength(3);
+      expect(blocking.map((b) => b.taskRun?.id).sort()).toEqual([...runIds].sort());
+
+      // GROUPED: one findMany for the WHOLE batch, never one findFirst per edge.
+      expect(counting.counts.taskRun.findMany).toBe(1);
+      expect(counting.counts.taskRun.findFirst).toBe(0);
+    }
+  );
+
+  heteroRunOpsPostgresTest(
+    "findManyWaitpoints hydrates N parents' `connectedRuns` with ONE grouped join query + ONE grouped target query",
+    async ({ prisma17 }) => {
+      const seedStore = makeStore(prisma17);
+      const env = seedEnvironmentDedicated("cr");
+
+      const waitpointIds = ["wp_cr_1", "wp_cr_2", "wp_cr_3"];
+      const runIds = ["run_cr_1", "run_cr_2", "run_cr_3"];
+      for (const [i, waitpointId] of waitpointIds.entries()) {
+        await prisma17.waitpoint.create({
+          data: {
+            id: waitpointId,
+            friendlyId: `${waitpointId}_friendly`,
+            type: "MANUAL",
+            status: "PENDING",
+            idempotencyKey: `idem_${waitpointId}`,
+            userProvidedIdempotencyKey: false,
+            projectId: env.project.id,
+            environmentId: env.environment.id,
+          },
+        });
+        await seedStore.createRun(
+          buildCreateRunInput({
+            runId: runIds[i],
+            friendlyId: `${runIds[i]}_friendly`,
+            organizationId: env.organization.id,
+            projectId: env.project.id,
+            runtimeEnvironmentId: env.environment.id,
+          })
+        );
+        // One connection per waitpoint, to its own distinct run.
+        await seedStore.blockRunWithWaitpointEdges({
+          runId: runIds[i],
+          waitpointIds: [waitpointId],
+          projectId: env.project.id,
+        });
+      }
+
+      const counting = countingClient(prisma17, ["waitpointRunConnection", "taskRun"]);
+      const readStore = makeStore(counting.client);
+
+      const rows = (await readStore.findManyWaitpoints({
+        where: { id: { in: waitpointIds } },
+        include: { connectedRuns: { select: { id: true, friendlyId: true } } },
+      })) as { id: string; connectedRuns: { id: string; friendlyId: string }[] }[];
+
+      expect(rows).toHaveLength(3);
+      const byWaitpointId = new Map(rows.map((r) => [r.id, r.connectedRuns]));
+      for (const [i, waitpointId] of waitpointIds.entries()) {
+        const connected = byWaitpointId.get(waitpointId) ?? [];
+        expect(connected).toHaveLength(1);
+        expect(connected[0].id).toBe(runIds[i]);
+      }
+
+      // GROUPED: one bounded join query (raw, ROW_NUMBER-per-parent) + one target query for the
+      // WHOLE batch, never one pair per parent. The bounded hydrator replaces the delegate
+      // `waitpointRunConnection.findMany` with a single `$queryRaw`.
+      expect(counting.queryRaw.count).toBe(1);
+      expect(counting.counts.waitpointRunConnection.findMany).toBe(0);
+      expect(counting.counts.taskRun.findMany).toBe(1);
+      expect(counting.counts.taskRun.findFirst).toBe(0);
+    }
+  );
+});
diff --git a/internal-packages/run-store/src/PostgresRunStore.hydratorSelectPushdown.test.ts b/internal-packages/run-store/src/PostgresRunStore.hydratorSelectPushdown.test.ts
new file mode 100644
index 0000000000..0db044bd94
--- /dev/null
+++ b/internal-packages/run-store/src/PostgresRunStore.hydratorSelectPushdown.test.ts
@@ -0,0 +1,226 @@
+// RED→GREEN: the dedicated-schema relation hydrators (`batchHydrateJoinRelation` /
+// `batchHydrateEdgeTarget`) fetch the target row's FULL columns (no `select`) and only strip fields
+// in JS afterwards via `applyProjection`. At prod scale (a 6.68B-row `TaskRun`) that over-fetches
+// every wide TOASTed column (`payload`/`output`/`context`) even when the caller only asked for
+// `friendlyId`. The RESULT is identical with/without the fix (`applyProjection` trims either way),
+// so this asserts the QUERY SHAPE Prisma actually receives, via a `$extends` query hook on a REAL
+// `heteroRunOpsPostgresTest.prisma17` client — the DB still runs the query, this only observes it.
+
+import { heteroRunOpsPostgresTest } from "@internal/testcontainers";
+import type { RunOpsPrismaClient } from "@internal/run-ops-database";
+import { describe, expect } from "vitest";
+import { PostgresRunStore } from "./PostgresRunStore.js";
+import type { CreateRunInput } from "./types.js";
+
+function seedEnvironmentDedicated(suffix: string) {
+  return {
+    organization: { id: `org_${suffix}` },
+    project: { id: `proj_${suffix}` },
+    environment: { id: `env_${suffix}` },
+  };
+}
+
+function buildCreateRunInput(params: {
+  runId: string;
+  friendlyId: string;
+  organizationId: string;
+  projectId: string;
+  runtimeEnvironmentId: string;
+}): CreateRunInput {
+  return {
+    data: {
+      id: params.runId,
+      engine: "V2",
+      status: "PENDING",
+      friendlyId: params.friendlyId,
+      runtimeEnvironmentId: params.runtimeEnvironmentId,
+      environmentType: "DEVELOPMENT",
+      organizationId: params.organizationId,
+      projectId: params.projectId,
+      taskIdentifier: "my-task",
+      payload: '{"hello":"world"}',
+      payloadType: "application/json",
+      traceContext: { trace: "ctx" },
+      traceId: `trace_${params.runId}`,
+      spanId: `span_${params.runId}`,
+      runTags: [],
+      queue: "task/my-task",
+      isTest: false,
+      taskEventStore: "taskEvent",
+      depth: 0,
+      createdAt: new Date("2024-01-01T00:00:00.000Z"),
+    },
+    snapshot: {
+      engine: "V2",
+      executionStatus: "RUN_CREATED",
+      description: "Run was created",
+      runStatus: "PENDING",
+      environmentId: params.runtimeEnvironmentId,
+      environmentType: "DEVELOPMENT",
+      projectId: params.projectId,
+      organizationId: params.organizationId,
+    },
+  };
+}
+
+function makeStore(prisma: RunOpsPrismaClient) {
+  return new PostgresRunStore({
+    prisma: prisma as never,
+    readOnlyPrisma: prisma as never,
+    schemaVariant: "dedicated",
+  });
+}
+
+// Wraps `taskRun.findMany` with a REAL Prisma Client Extension query hook: every call's `args` is
+// captured, then delegated unchanged to `query(args)` so the DB still executes it. This is
+// observation, not a mock — the extension can't fabricate a result, only see what's sent.
+function withCapturedTaskRunFindManyArgs(real: RunOpsPrismaClient) {
+  const capturedArgs: Record<string, unknown>[] = [];
+  const extended = (real as unknown as { $extends: (config: unknown) => unknown }).$extends({
+    query: {
+      taskRun: {
+        findMany({
+          args,
+          query,
+        }: {
+          args: Record<string, unknown>;
+          query: (args: unknown) => Promise<unknown>;
+        }) {
+          capturedArgs.push(args);
+          return query(args);
+        },
+      },
+    },
+  });
+  return { client: extended as RunOpsPrismaClient, capturedArgs };
+}
+
+describe("PostgresRunStore dedicated relation hydrators — target findMany select pushdown", () => {
+  heteroRunOpsPostgresTest(
+    "hydrateConnectedRuns narrows the target taskRun.findMany to the caller's select instead of fetching the full row",
+    async ({ prisma17 }) => {
+      const seedStore = makeStore(prisma17);
+      const env = seedEnvironmentDedicated("select_pushdown");
+
+      const runId = "run_select_pushdown";
+      const waitpointId = "wp_select_pushdown";
+
+      await prisma17.waitpoint.create({
+        data: {
+          id: waitpointId,
+          friendlyId: `${waitpointId}_friendly`,
+          type: "MANUAL",
+          status: "PENDING",
+          idempotencyKey: `idem_${waitpointId}`,
+          userProvidedIdempotencyKey: false,
+          projectId: env.project.id,
+          environmentId: env.environment.id,
+        },
+      });
+
+      await seedStore.createRun(
+        buildCreateRunInput({
+          runId,
+          friendlyId: `${runId}_friendly`,
+          organizationId: env.organization.id,
+          projectId: env.project.id,
+          runtimeEnvironmentId: env.environment.id,
+        })
+      );
+
+      // Seeds BOTH the TaskRunWaitpoint edge and the WaitpointRunConnection join row that
+      // `connectedRuns` reads from.
+      await seedStore.blockRunWithWaitpointEdges({
+        runId,
+        waitpointIds: [waitpointId],
+        projectId: env.project.id,
+      });
+
+      const { client: capturingClient, capturedArgs } = withCapturedTaskRunFindManyArgs(prisma17);
+      const readStore = makeStore(capturingClient);
+
+      const waitpoint = (await readStore.findWaitpoint({
+        where: { id: waitpointId },
+        include: { connectedRuns: { select: { friendlyId: true } } },
+      })) as { connectedRuns: { friendlyId: string }[] } | null;
+
+      expect(capturedArgs).toHaveLength(1);
+      const targetArgs = capturedArgs[0] as { where: unknown; select?: Record<string, unknown> };
+
+      // THE FIX: the target `findMany` carries a `select` narrowed to the caller's projection (plus
+      // the `id` the hydrator keys off), never a bare where-only (= full row) query.
+      expect(targetArgs.select).toBeDefined();
+      expect(targetArgs.select).toMatchObject({ friendlyId: true, id: true });
+      expect(targetArgs.select?.payload).toBeUndefined();
+      expect(targetArgs.select?.output).toBeUndefined();
+      expect(targetArgs.select?.context).toBeUndefined();
+
+      // `applyProjection` still trims correctly: exactly `{ friendlyId }`, no `id` leak, no wide
+      // columns — proving the pushdown didn't change the caller-visible result.
+      expect(waitpoint?.connectedRuns).toHaveLength(1);
+      expect(waitpoint?.connectedRuns[0]).toEqual({ friendlyId: `${runId}_friendly` });
+    }
+  );
+
+  heteroRunOpsPostgresTest(
+    "hydrateEdgeTaskRun (batchHydrateEdgeTarget) narrows the target taskRun.findMany to the caller's select instead of fetching the full row",
+    async ({ prisma17 }) => {
+      const seedStore = makeStore(prisma17);
+      const env = seedEnvironmentDedicated("edge_pushdown");
+
+      const runId = "run_edge_pushdown";
+      const waitpointId = "wp_edge_pushdown";
+
+      await prisma17.waitpoint.create({
+        data: {
+          id: waitpointId,
+          friendlyId: `${waitpointId}_friendly`,
+          type: "MANUAL",
+          status: "PENDING",
+          idempotencyKey: `idem_${waitpointId}`,
+          userProvidedIdempotencyKey: false,
+          projectId: env.project.id,
+          environmentId: env.environment.id,
+        },
+      });
+
+      await seedStore.createRun(
+        buildCreateRunInput({
+          runId,
+          friendlyId: `${runId}_friendly`,
+          organizationId: env.organization.id,
+          projectId: env.project.id,
+          runtimeEnvironmentId: env.environment.id,
+        })
+      );
+
+      await seedStore.blockRunWithWaitpointEdges({
+        runId,
+        waitpointIds: [waitpointId],
+        projectId: env.project.id,
+      });
+
+      const { client: capturingClient, capturedArgs } = withCapturedTaskRunFindManyArgs(prisma17);
+      const readStore = makeStore(capturingClient);
+
+      // TaskRunWaitpoint's `taskRun` relation is the dedicated `hydrateEdgeTaskRun` ->
+      // `batchHydrateEdgeTarget` path (the scalar-FK-on-the-parent variant).
+      const edges = (await readStore.findManyTaskRunWaitpoints({
+        where: { waitpointId },
+        select: { taskRun: { select: { friendlyId: true } } },
+      })) as { taskRun: { friendlyId: string } | null }[];
+
+      expect(capturedArgs).toHaveLength(1);
+      const targetArgs = capturedArgs[0] as { where: unknown; select?: Record<string, unknown> };
+
+      expect(targetArgs.select).toBeDefined();
+      expect(targetArgs.select).toMatchObject({ friendlyId: true, id: true });
+      expect(targetArgs.select?.payload).toBeUndefined();
+      expect(targetArgs.select?.output).toBeUndefined();
+      expect(targetArgs.select?.context).toBeUndefined();
+
+      expect(edges).toHaveLength(1);
+      expect(edges[0].taskRun).toEqual({ friendlyId: `${runId}_friendly` });
+    }
+  );
+});
diff --git a/internal-packages/run-store/src/PostgresRunStore.sharedHydratedTarget.test.ts b/internal-packages/run-store/src/PostgresRunStore.sharedHydratedTarget.test.ts
new file mode 100644
index 0000000000..482f532f5d
--- /dev/null
+++ b/internal-packages/run-store/src/PostgresRunStore.sharedHydratedTarget.test.ts
@@ -0,0 +1,139 @@
+// RED→GREEN: bare-projection dedicated-relation hydration (e.g. `connectedRuns: true`) shares ONE
+// target object reference across every parent bucket that links it, so an in-place mutation on one
+// parent's hydrated target aliases into another's. Two waitpoints connecting to the SAME run should
+// come back with DISTINCT `TaskRun` objects, not the same instance.
+
+import { heteroRunOpsPostgresTest } from "@internal/testcontainers";
+import type { RunOpsPrismaClient } from "@internal/run-ops-database";
+import { describe, expect } from "vitest";
+import { PostgresRunStore } from "./PostgresRunStore.js";
+import type { CreateRunInput } from "./types.js";
+
+function seedEnvironmentDedicated(suffix: string) {
+  return {
+    organization: { id: `org_${suffix}` },
+    project: { id: `proj_${suffix}` },
+    environment: { id: `env_${suffix}` },
+  };
+}
+
+function buildCreateRunInput(params: {
+  runId: string;
+  friendlyId: string;
+  organizationId: string;
+  projectId: string;
+  runtimeEnvironmentId: string;
+}): CreateRunInput {
+  return {
+    data: {
+      id: params.runId,
+      engine: "V2",
+      status: "PENDING",
+      friendlyId: params.friendlyId,
+      runtimeEnvironmentId: params.runtimeEnvironmentId,
+      environmentType: "DEVELOPMENT",
+      organizationId: params.organizationId,
+      projectId: params.projectId,
+      taskIdentifier: "my-task",
+      payload: '{"hello":"world"}',
+      payloadType: "application/json",
+      traceContext: { trace: "ctx" },
+      traceId: `trace_${params.runId}`,
+      spanId: `span_${params.runId}`,
+      runTags: [],
+      queue: "task/my-task",
+      isTest: false,
+      taskEventStore: "taskEvent",
+      depth: 0,
+      createdAt: new Date("2024-01-01T00:00:00.000Z"),
+    },
+    snapshot: {
+      engine: "V2",
+      executionStatus: "RUN_CREATED",
+      description: "Run was created",
+      runStatus: "PENDING",
+      environmentId: params.runtimeEnvironmentId,
+      environmentType: "DEVELOPMENT",
+      projectId: params.projectId,
+      organizationId: params.organizationId,
+    },
+  };
+}
+
+function makeStore(prisma: RunOpsPrismaClient) {
+  return new PostgresRunStore({
+    prisma: prisma as never,
+    readOnlyPrisma: prisma as never,
+    schemaVariant: "dedicated",
+  });
+}
+
+describe("PostgresRunStore dedicated relation hydrators — shared target identity (bare projection)", () => {
+  heteroRunOpsPostgresTest(
+    "findManyWaitpoints hydrates bare `connectedRuns: true` for two waitpoints sharing one run as DISTINCT objects",
+    async ({ prisma17 }) => {
+      const store = makeStore(prisma17);
+      const env = seedEnvironmentDedicated("shared_target");
+
+      const runId = "run_shared_target";
+      const waitpointIds = ["wp_shared_1", "wp_shared_2"];
+
+      await store.createRun(
+        buildCreateRunInput({
+          runId,
+          friendlyId: "run_shared_target_friendly",
+          organizationId: env.organization.id,
+          projectId: env.project.id,
+          runtimeEnvironmentId: env.environment.id,
+        })
+      );
+
+      for (const waitpointId of waitpointIds) {
+        await prisma17.waitpoint.create({
+          data: {
+            id: waitpointId,
+            friendlyId: `${waitpointId}_friendly`,
+            type: "MANUAL",
+            status: "PENDING",
+            idempotencyKey: `idem_${waitpointId}`,
+            userProvidedIdempotencyKey: false,
+            projectId: env.project.id,
+            environmentId: env.environment.id,
+          },
+        });
+      }
+
+      // Both waitpoints connect to the SAME run: the target-row `findMany` in
+      // `batchHydrateJoinRelation` returns ONE row for the run, shared across both parents' buckets.
+      await store.blockRunWithWaitpointEdges({
+        runId,
+        waitpointIds,
+        projectId: env.project.id,
+      });
+
+      // Bare projection (`connectedRuns: true`, no sub-select) — the buggy path: `applyProjection`
+      // returns the row UNCHANGED instead of a fresh object.
+      const rows = (await store.findManyWaitpoints({
+        where: { id: { in: waitpointIds } },
+        include: { connectedRuns: true },
+      })) as { id: string; connectedRuns: { id: string; friendlyId: string }[] }[];
+
+      expect(rows).toHaveLength(2);
+      const byWaitpointId = new Map(rows.map((r) => [r.id, r.connectedRuns]));
+      const target1 = byWaitpointId.get("wp_shared_1")?.[0];
+      const target2 = byWaitpointId.get("wp_shared_2")?.[0];
+
+      expect(target1).toBeDefined();
+      expect(target2).toBeDefined();
+      expect(target1!.id).toBe(runId);
+      expect(target2!.id).toBe(runId);
+
+      // THE BUG: both hydrated targets are the SAME object reference.
+      expect(target1).not.toBe(target2);
+
+      // Mutating a top-level field on one parent's hydrated target must NOT change the other's.
+      (target1 as { friendlyId: string }).friendlyId = "mutated";
+      expect(target2!.friendlyId).not.toBe("mutated");
+    }
+  );
+});
diff --git a/internal-packages/run-store/src/PostgresRunStore.ts b/internal-packages/run-store/src/PostgresRunStore.ts
index 5d8ea6c8df..fa8df51f28 100644
--- a/internal-packages/run-store/src/PostgresRunStore.ts
+++ b/internal-packages/run-store/src/PostgresRunStore.ts
@@ -89,6 +89,10 @@ export interface RunOpsTransactionalClient extends RunOpsCapableClient {
  */
 export type RunStoreSchemaVariant = "legacy" | "dedicated";
 
+// Mirrors the webapp's `CONNECTED_RUNS_DISPLAY_LIMIT`
+// (apps/webapp/app/presenters/v3/WaitpointPresenter.server.ts) — keep the values in sync.
+export const CONNECTED_RUNS_LIMIT = 5;
+
 export type PostgresRunStoreOptions = {
   prisma: RunOpsCapableClient;
   readOnlyPrisma: RunOpsCapableClient;
@@ -99,13 +103,15 @@ export type PostgresRunStoreOptions = {
 // A caller sub-select for a relation: `{ select?, include? }` or `true` for a bare `key: true`.
 type SubProjection = { select?: any; include?: any } | true | undefined;
 
-// Hydrates one dedicated-schema relation for a single parent row, honoring the caller's sub-projection.
+// Hydrates one dedicated-schema relation for a WHOLE batch of parent rows in one grouped pass:
+// one query for the join/target rows spanning every parent id, never one per parent. Returns a
+// Map keyed by parent `id` to the already-defaulted (null / []) hydrated value.
 type DedicatedRelationHydrator = (
   client: RunOpsCapableClient,
-  parent: Record<string, unknown>,
+  parents: Record<string, unknown>[],
   projection: { select?: any; include?: any } | undefined,
   store: PostgresRunStore
-) => Promise<unknown>;
+) => Promise<Map<string, unknown>>;
 
 // The dedicated-schema relation keys (with hydrators) for a single Prisma model.
 type DedicatedRelationSpec = Record<string, DedicatedRelationHydrator>;
@@ -119,13 +125,23 @@ function projectionOf(sub: SubProjection): { select?: any; include?: any } | und
 }
 
 // Apply a caller sub-projection to a hydrated row (or array) so only requested fields remain.
+//
+// Bare-projection path (no `select`): return a SHALLOW CLONE, not the row itself, so every parent
+// bucket that links the same target gets a distinct top-level object — two parents sharing one
+// target (e.g. two waitpoints connected to the same run) must not alias through a shared reference.
+// This only protects top-level mutation; a deep in-place mutation of a nested field would still
+// alias, which matches the realistic redaction/patch cases and avoids a costly deep clone on hot
+// reads.
 function applyProjection<T extends Record<string, unknown> | null>(
   row: T,
   projection: { select?: any; include?: any } | undefined
 ): T {
-  if (!row || !projection?.select) {
+  if (!row) {
     return row;
   }
+  if (!projection?.select) {
+    return { ...row } as T;
+  }
   const keys = Object.keys(projection.select).filter((k) => projection.select[k]);
   const out: Record<string, unknown> = {};
   for (const k of keys) {
@@ -175,153 +191,247 @@ function stripDedicatedRelations(
   return { stripped: args, requested };
 }
 
-// --- per-model dedicated-schema relation hydrators ---
+// --- per-model dedicated-schema relation hydrators (batched across the WHOLE parent array) ---
 
-// Waitpoint where completedByTaskRunId = run.id (the @unique scalar back-pointer); at most one.
-const hydrateAssociatedWaitpoint: DedicatedRelationHydrator = async (
-  client,
-  parent,
-  projection
-) => {
-  const wp = (await client.waitpoint.findFirst({
-    where: { completedByTaskRunId: parent.id as string },
-  })) as Record<string, unknown> | null;
-  return applyProjection(wp, projection);
-};
+// Narrows a hydrator's target `findMany` to the caller's `select` (avoids fetching the wide
+// TOASTed columns just to strip them in `applyProjection`); a bare/`include` projection stays a
+// full-row fetch. `keepKeys` are the column(s) the hydrator's Map is keyed on.
+function targetFindManyArgs(
+  where: unknown,
+  projection: { select?: any; include?: any } | undefined,
+  keepKeys: string[]
+): { where: unknown; select?: Record<string, unknown> } {
+  if (projection?.select) {
+    const select: Record<string, unknown> = { ...projection.select };
+    for (const key of keepKeys) {
+      select[key] = true;
+    }
+    return { where, select };
+  }
+  return { where };
+}
 
-// Display connections for a run: WaitpointRunConnection → Waitpoint rows.
-const hydrateConnectedWaitpoints: DedicatedRelationHydrator = async (
-  client,
-  parent,
-  projection
-) => {
-  const join = client.waitpointRunConnection;
-  if (!join) {
-    return [];
+// Generic to-many relation reached via an explicit join model: one grouped query for the join rows
+// spanning every parent id, then one grouped query for the distinct target rows, then an in-memory
+// (DB-free) assembly per parent. `joinParentField`/`joinTargetField` name the join row's two FK
+// columns; `targetDelegate` is the model the join points at.
+async function batchHydrateJoinRelation(
+  join: RunOpsDelegate<"findMany"> | undefined,
+  targetDelegate: RunOpsDelegate<"findMany">,
+  parentIds: string[],
+  joinParentField: string,
+  joinTargetField: string,
+  projection: { select?: any; include?: any } | undefined
+): Promise<Map<string, unknown[]>> {
+  const byParent = new Map<string, unknown[]>(parentIds.map((id) => [id, []]));
+  if (!join || parentIds.length === 0) {
+    return byParent;
   }
   const links = (await join.findMany({
-    where: { taskRunId: parent.id as string },
-    select: { waitpointId: true },
-  })) as { waitpointId: string }[];
+    where: { [joinParentField]: { in: parentIds } },
+    select: { [joinParentField]: true, [joinTargetField]: true },
+  })) as Record<string, string>[];
   if (links.length === 0) {
-    return [];
+    return byParent;
+  }
+  const targetIds = [...new Set(links.map((l) => l[joinTargetField]))];
+  const rows = (await targetDelegate.findMany(
+    targetFindManyArgs({ id: { in: targetIds } }, projection, ["id"])
+  )) as Record<string, unknown>[];
+  const byTargetId = new Map(rows.map((r) => [r.id as string, r]));
+  for (const link of links) {
+    const target = byTargetId.get(link[joinTargetField]);
+    const bucket = byParent.get(link[joinParentField]);
+    if (target && bucket) {
+      bucket.push(applyProjection(target, projection));
+    }
   }
-  const rows = (await client.waitpoint.findMany({
-    where: { id: { in: links.map((l) => l.waitpointId) } },
-  })) as Record<string, unknown>[];
-  return rows.map((r) => applyProjection(r, projection));
-};
+  return byParent;
+}
 
-// Completed waitpoints for a snapshot: CompletedWaitpoint join → Waitpoint rows.
-const hydrateCompletedWaitpoints: DedicatedRelationHydrator = async (
+// Waitpoint where completedByTaskRunId = run.id (the @unique scalar back-pointer); at most one.
+const hydrateAssociatedWaitpoint: DedicatedRelationHydrator = async (
   client,
-  parent,
+  parents,
   projection
 ) => {
-  const join = client.completedWaitpoint;
-  if (!join) {
-    return [];
-  }
-  const links = (await join.findMany({
-    where: { snapshotId: parent.id as string },
-    select: { waitpointId: true },
-  })) as { waitpointId: string }[];
-  if (links.length === 0) {
-    return [];
+  const parentIds = parents.map((p) => p.id as string);
+  const byParent = new Map<string, unknown>(parentIds.map((id) => [id, null]));
+  if (parentIds.length === 0) {
+    return byParent;
+  }
+  const rows = (await client.waitpoint.findMany(
+    targetFindManyArgs({ completedByTaskRunId: { in: parentIds } }, projection, [
+      "completedByTaskRunId",
+    ])
+  )) as Record<string, unknown>[];
+  for (const row of rows) {
+    const runId = row.completedByTaskRunId as string | undefined;
+    if (runId && byParent.has(runId)) {
+      byParent.set(runId, applyProjection(row, projection));
+    }
   }
-  const rows = (await client.waitpoint.findMany({
-    where: { id: { in: links.map((l) => l.waitpointId) } },
-  })) as Record<string, unknown>[];
-  return rows.map((r) => applyProjection(r, projection));
+  return byParent;
 };
 
+// Display connections for a run: WaitpointRunConnection → Waitpoint rows.
+const hydrateConnectedWaitpoints: DedicatedRelationHydrator = async (client, parents, projection) =>
+  batchHydrateJoinRelation(
+    client.waitpointRunConnection,
+    client.waitpoint,
+    parents.map((p) => p.id as string),
+    "taskRunId",
+    "waitpointId",
+    projection
+  );
+
+// Completed waitpoints for a snapshot: CompletedWaitpoint join → Waitpoint rows.
+const hydrateCompletedWaitpoints: DedicatedRelationHydrator = async (client, parents, projection) =>
+  batchHydrateJoinRelation(
+    client.completedWaitpoint,
+    client.waitpoint,
+    parents.map((p) => p.id as string),
+    "snapshotId",
+    "waitpointId",
+    projection
+  );
+
 // Runs a waitpoint is blocking: TaskRunWaitpoint rows keyed by waitpointId. A nested `taskRun`
 // select (the run-engine's getWaitpoint shape) is resolved from the scalar TaskRunWaitpoint.taskRunId.
-const hydrateBlockingTaskRuns: DedicatedRelationHydrator = async (client, parent, projection) => {
+const hydrateBlockingTaskRuns: DedicatedRelationHydrator = async (client, parents, projection) => {
+  const parentIds = parents.map((p) => p.id as string);
+  const byParent = new Map<string, unknown[]>(parentIds.map((id) => [id, []]));
+  if (parentIds.length === 0) {
+    return byParent;
+  }
   const edges = (await client.taskRunWaitpoint.findMany({
-    where: { waitpointId: parent.id as string },
+    where: { waitpointId: { in: parentIds } },
   })) as Record<string, unknown>[];
   const nestedTaskRun = projection?.select?.taskRun;
-  if (!nestedTaskRun) {
-    return edges;
-  }
-  const runProjection = projectionOf(nestedTaskRun as SubProjection);
-  return Promise.all(
-    edges.map(async (edge) => {
-      const run = (await client.taskRun.findFirst({
-        where: { id: edge.taskRunId as string },
-      })) as Record<string, unknown> | null;
-      return { ...edge, taskRun: applyProjection(run, runProjection) };
-    })
-  );
+  const runProjection = nestedTaskRun ? projectionOf(nestedTaskRun as SubProjection) : undefined;
+  let byRunId = new Map<string, Record<string, unknown>>();
+  if (nestedTaskRun) {
+    const runIds = [...new Set(edges.map((e) => e.taskRunId as string))];
+    const runs = (
+      runIds.length > 0
+        ? await client.taskRun.findMany(
+            targetFindManyArgs({ id: { in: runIds } }, runProjection, ["id"])
+          )
+        : []
+    ) as Record<string, unknown>[];
+    byRunId = new Map(runs.map((r) => [r.id as string, r]));
+  }
+  for (const edge of edges) {
+    const bucket = byParent.get(edge.waitpointId as string);
+    if (!bucket) continue;
+    bucket.push(
+      nestedTaskRun
+        ? {
+            ...edge,
+            taskRun: applyProjection(byRunId.get(edge.taskRunId as string) ?? null, runProjection),
+          }
+        : edge
+    );
+  }
+  return byParent;
 };
 
-// Display connections for a waitpoint: WaitpointRunConnection → TaskRun rows.
-const hydrateConnectedRuns: DedicatedRelationHydrator = async (client, parent, projection) => {
-  const join = client.waitpointRunConnection;
-  if (!join) {
-    return [];
-  }
-  const links = (await join.findMany({
-    where: { waitpointId: parent.id as string },
-    select: { taskRunId: true },
-  })) as { taskRunId: string }[];
+// Display connections for a waitpoint: WaitpointRunConnection → TaskRun rows. Bounded per parent to
+// CONNECTED_RUNS_LIMIT via a window function + existence-JOIN to TaskRun, mirroring the id-list
+// helper findWaitpointConnectedRunIds: a dangling (run-less) connection row never occupies a LIMIT
+// slot, and a heavily-fanned-in waitpoint never hydrates an unbounded connectedRuns list. This is
+// the DISPLAY relation only — functional blocking reads (hydrateBlockingTaskRuns) stay uncapped.
+const hydrateConnectedRuns: DedicatedRelationHydrator = async (client, parents, projection) => {
+  const parentIds = parents.map((p) => p.id as string);
+  const byParent = new Map<string, unknown[]>(parentIds.map((id) => [id, []]));
+  if (parentIds.length === 0) {
+    return byParent;
+  }
+  // One grouped query for the bounded edges across every parent: ROW_NUMBER partitioned per
+  // waitpoint keeps at most CONNECTED_RUNS_LIMIT rows per parent (uses @@index([waitpointId])).
+  const links = (await client.$queryRaw`
+    SELECT ranked."waitpointId" AS "waitpointId", ranked."taskRunId" AS "taskRunId"
+    FROM (
+      SELECT c."waitpointId", c."taskRunId",
+        ROW_NUMBER() OVER (PARTITION BY c."waitpointId" ORDER BY c."id") AS rn
+      FROM "WaitpointRunConnection" c
+      JOIN "TaskRun" t ON t."id" = c."taskRunId"
+      WHERE c."waitpointId" = ANY(${parentIds}::text[])
+    ) ranked
+    WHERE ranked.rn <= ${CONNECTED_RUNS_LIMIT}
+  `) as { waitpointId: string; taskRunId: string }[];
   if (links.length === 0) {
-    return [];
+    return byParent;
+  }
+  const targetIds = [...new Set(links.map((l) => l.taskRunId))];
+  const rows = (await client.taskRun.findMany(
+    targetFindManyArgs({ id: { in: targetIds } }, projection, ["id"])
+  )) as Record<string, unknown>[];
+  const byTargetId = new Map(rows.map((r) => [r.id as string, r]));
+  for (const link of links) {
+    const target = byTargetId.get(link.taskRunId);
+    const bucket = byParent.get(link.waitpointId);
+    if (target && bucket) {
+      bucket.push(applyProjection(target, projection));
+    }
   }
-  const rows = (await client.taskRun.findMany({
-    where: { id: { in: links.map((l) => l.taskRunId) } },
-  })) as Record<string, unknown>[];
-  return rows.map((r) => applyProjection(r, projection));
+  return byParent;
 };
 
 // Snapshots that completed a waitpoint: CompletedWaitpoint join → TaskRunExecutionSnapshot rows.
 const hydrateCompletedExecutionSnapshots: DedicatedRelationHydrator = async (
   client,
-  parent,
+  parents,
   projection
-) => {
-  const join = client.completedWaitpoint;
-  if (!join) {
-    return [];
-  }
-  const links = (await join.findMany({
-    where: { waitpointId: parent.id as string },
-    select: { snapshotId: true },
-  })) as { snapshotId: string }[];
-  if (links.length === 0) {
-    return [];
-  }
-  const rows = (await client.taskRunExecutionSnapshot.findMany({
-    where: { id: { in: links.map((l) => l.snapshotId) } },
-  })) as Record<string, unknown>[];
-  return rows.map((r) => applyProjection(r, projection));
-};
-
-// The waitpoint a block edge points at, resolved from the edge's scalar `waitpointId`. The edge's
-// own client only finds a co-resident token; the router re-resolves cross-DB.
-const hydrateEdgeWaitpoint: DedicatedRelationHydrator = async (client, parent, projection) => {
-  const waitpointId = parent.waitpointId as string | undefined;
-  if (!waitpointId) {
-    return null;
-  }
-  const wp = (await client.waitpoint.findFirst({
-    where: { id: waitpointId },
-  })) as Record<string, unknown> | null;
-  return applyProjection(wp, projection);
-};
+) =>
+  batchHydrateJoinRelation(
+    client.completedWaitpoint,
+    client.taskRunExecutionSnapshot,
+    parents.map((p) => p.id as string),
+    "waitpointId",
+    "snapshotId",
+    projection
+  );
 
-// The run a block edge belongs to, resolved from the edge's scalar `taskRunId`.
-const hydrateEdgeTaskRun: DedicatedRelationHydrator = async (client, parent, projection) => {
-  const taskRunId = parent.taskRunId as string | undefined;
-  if (!taskRunId) {
-    return null;
+// The waitpoint each block edge points at, resolved from its scalar `waitpointId`. The edge's own
+// client only finds a co-resident token; the router re-resolves cross-DB.
+const hydrateEdgeWaitpoint: DedicatedRelationHydrator = async (client, parents, projection) =>
+  batchHydrateEdgeTarget(client.waitpoint, parents, "waitpointId", projection);
+
+// The run each block edge belongs to, resolved from its scalar `taskRunId`.
+const hydrateEdgeTaskRun: DedicatedRelationHydrator = async (client, parents, projection) =>
+  batchHydrateEdgeTarget(client.taskRun, parents, "taskRunId", projection);
+
+// Generic to-one relation reached via a scalar FK ON the parent itself (not a join model): one
+// grouped target query for every distinct FK value across the batch.
+async function batchHydrateEdgeTarget(
+  targetDelegate: RunOpsDelegate<"findMany">,
+  parents: Record<string, unknown>[],
+  fkField: string,
+  projection: { select?: any; include?: any } | undefined
+): Promise<Map<string, unknown>> {
+  const byParent = new Map<string, unknown>();
+  const targetIds: string[] = [];
+  for (const p of parents) {
+    byParent.set(p.id as string, null);
+    const fk = p[fkField] as string | undefined;
+    if (fk) targetIds.push(fk);
+  }
+  if (targetIds.length === 0) {
+    return byParent;
+  }
+  const rows = (await targetDelegate.findMany(
+    targetFindManyArgs({ id: { in: [...new Set(targetIds)] } }, projection, ["id"])
+  )) as Record<string, unknown>[];
+  const byTargetId = new Map(rows.map((r) => [r.id as string, r]));
+  for (const p of parents) {
+    const fk = p[fkField] as string | undefined;
+    if (fk) {
+      byParent.set(p.id as string, applyProjection(byTargetId.get(fk) ?? null, projection));
+    }
   }
-  const run = (await client.taskRun.findFirst({
-    where: { id: taskRunId },
-  })) as Record<string, unknown> | null;
-  return applyProjection(run, projection);
-};
+  return byParent;
+}
 
 const TASK_RUN_DEDICATED: DedicatedRelationSpec = {
   associatedWaitpoint: hydrateAssociatedWaitpoint,
@@ -1444,15 +1554,72 @@ export class PostgresRunStore implements RunStore {
       cursor,
       ...stripped,
     })) as Record<string, unknown>[];
+    await this.#hydrateDedicatedRelations(
+      prisma as RunOpsCapableClient,
+      rows,
+      requested,
+      TASK_RUN_DEDICATED
+    );
+    return rows;
+  }
+
+  // Grouped replacement for `Promise.all(ids.map(id => findRun(id)))`: a thin wrapper over
+  // `findRuns` (so it inherits dedicated-relation hydration + read-your-writes client routing),
+  // bounding the whole id batch into one round trip instead of one per id.
+  findRunsByIds<S extends Prisma.TaskRunSelect>(
+    ids: string[],
+    args: { select: S },
+    client?: ReadClient
+  ): Promise<Map<string, Prisma.TaskRunGetPayload<{ select: S }>>>;
+  findRunsByIds<I extends Prisma.TaskRunInclude>(
+    ids: string[],
+    args: { include: I },
+    client?: ReadClient
+  ): Promise<Map<string, Prisma.TaskRunGetPayload<{ include: I }>>>;
+  findRunsByIds(ids: string[], client?: ReadClient): Promise<Map<string, TaskRun>>;
+  async findRunsByIds(
+    ids: string[],
+    argsOrClient?: { select?: Prisma.TaskRunSelect; include?: Prisma.TaskRunInclude } | ReadClient,
+    _client?: ReadClient
+  ): Promise<Map<string, unknown>> {
+    if (ids.length === 0) {
+      return new Map();
+    }
+    const hasSelectOrInclude =
+      argsOrClient != null &&
+      typeof argsOrClient === "object" &&
+      ("select" in argsOrClient || "include" in argsOrClient);
+    const args = hasSelectOrInclude
+      ? (argsOrClient as { select?: Prisma.TaskRunSelect; include?: Prisma.TaskRunInclude })
+      : undefined;
+    // Slot recovery mirrors `findRuns`'s overloads: when `argsOrClient` isn't a
+    // `{ select | include }` object it may itself BE the client (2-arg call) or be undefined
+    // with the client in the 3rd slot (an explicit `(ids, undefined, client)` call).
+    const client =
+      args === undefined ? ((argsOrClient as ReadClient | undefined) ?? _client) : _client;
+    // Force `id` into the projection so the map can key off it, even when the caller's select
+    // omits it — `findRuns` would otherwise strip it back out as an added-for-merge-only field.
+    const projected = args?.select
+      ? { select: { ...args.select, id: true } }
+      : args?.include
+        ? { include: args.include }
+        : {};
+    const rows = (await this.findRuns(
+      { where: { id: { in: ids } }, ...projected } as Parameters<PostgresRunStore["findRuns"]>[0],
+      client
+    )) as Record<string, unknown>[];
+    const byId = new Map<string, unknown>();
+    // Strip the id we force-injected for map keying when the caller's select did not ask for it,
+    // so returned values match the declared payload type and never leak an unrequested id.
+    const stripInjectedId = args?.select != null && !("id" in args.select);
     for (const row of rows) {
-      await this.#hydrateDedicatedRelations(
-        prisma as RunOpsCapableClient,
-        row,
-        requested,
-        TASK_RUN_DEDICATED
-      );
+      const key = row.id as string;
+      if (stripInjectedId) {
+        delete row.id;
+      }
+      byId.set(key, row);
     }
-    return rows;
+    return byId;
   }
 
   // --- run-ops persistence ---
@@ -1563,14 +1730,12 @@ export class PostgresRunStore implements RunStore {
       cursor,
       ...stripped,
     })) as Record<string, unknown>[];
-    for (const row of rows) {
-      await this.#hydrateDedicatedRelations(
-        prisma as RunOpsCapableClient,
-        row,
-        requested,
-        SNAPSHOT_DEDICATED
-      );
-    }
+    await this.#hydrateDedicatedRelations(
+      prisma as RunOpsCapableClient,
+      rows,
+      requested,
+      SNAPSHOT_DEDICATED
+    );
     return rows as Prisma.TaskRunExecutionSnapshotGetPayload<T>[];
   }
 
@@ -1710,23 +1875,34 @@ export class PostgresRunStore implements RunStore {
   // Reverse of `connectedRuns`: the run ids linked to a waitpoint. Co-resident with the RUN (the join
   // is written on the run's DB in blockRunWithWaitpointEdges), so the waitpoint's own store can MISS a
   // cross-DB run — the router fans this across BOTH DBs.
+  // Bounded to CONNECTED_RUNS_LIMIT via an existence-JOIN to TaskRun, mirroring the webapp's
+  // `#connectedRunIdsOn`: a dangling connection row (dedicated schema: FK-free `taskRunId`) can
+  // never occupy a LIMIT slot ahead of a real run, and a heavily-fanned-in waitpoint can never emit
+  // an unbounded id list.
   async findWaitpointConnectedRunIds(waitpointId: string, client?: ReadClient): Promise<string[]> {
     const prisma = client ?? this.readOnlyPrisma;
 
     const joinDelegate = (prisma as RunOpsCapableClient).waitpointRunConnection;
     if (this.schemaVariant === "dedicated" && joinDelegate) {
-      const links = (await joinDelegate.findMany({
-        where: { waitpointId },
-        select: { taskRunId: true },
-      })) as { taskRunId: string }[];
-      return links.map((l) => l.taskRunId);
+      const rows = await prisma.$queryRaw<{ taskRunId: string }[]>`
+        SELECT c."taskRunId" AS "taskRunId"
+        FROM "WaitpointRunConnection" c
+        JOIN "TaskRun" t ON t."id" = c."taskRunId"
+        WHERE c."waitpointId" = ${waitpointId}
+        LIMIT ${CONNECTED_RUNS_LIMIT}
+      `;
+      return rows.map((row) => row.taskRunId);
     }
 
     // Legacy implicit M2M `_WaitpointRunConnections`: A = TaskRun.id, B = Waitpoint.id (alphabetical).
-    const result = await prisma.$queryRaw<{ A: string }[]>`
-      SELECT "A" FROM "_WaitpointRunConnections" WHERE "B" = ${waitpointId}
+    const rows = await prisma.$queryRaw<{ A: string }[]>`
+      SELECT c."A" AS "A"
+      FROM "_WaitpointRunConnections" c
+      JOIN "TaskRun" t ON t."id" = c."A"
+      WHERE c."B" = ${waitpointId}
+      LIMIT ${CONNECTED_RUNS_LIMIT}
     `;
-    return result.map((r) => r.A);
+    return rows.map((row) => row.A);
   }
 
   // Reverse of `completedExecutionSnapshots`: the snapshot ids that completed a waitpoint. The join is
@@ -1949,14 +2125,12 @@ export class PostgresRunStore implements RunStore {
       cursor,
       ...stripped,
     })) as Record<string, unknown>[];
-    for (const row of rows) {
-      await this.#hydrateDedicatedRelations(
-        prisma as RunOpsCapableClient,
-        row,
-        requested,
-        WAITPOINT_DEDICATED
-      );
-    }
+    await this.#hydrateDedicatedRelations(
+      prisma as RunOpsCapableClient,
+      rows,
+      requested,
+      WAITPOINT_DEDICATED
+    );
     return rows as Prisma.WaitpointGetPayload<T>[];
   }
 
@@ -2019,14 +2193,12 @@ export class PostgresRunStore implements RunStore {
       cursor,
       ...stripped,
     })) as Record<string, unknown>[];
-    for (const row of rows) {
-      await this.#hydrateDedicatedRelations(
-        prisma as RunOpsCapableClient,
-        row,
-        requested,
-        TASK_RUN_WAITPOINT_DEDICATED
-      );
-    }
+    await this.#hydrateDedicatedRelations(
+      prisma as RunOpsCapableClient,
+      rows,
+      requested,
+      TASK_RUN_WAITPOINT_DEDICATED
+    );
     return rows as Prisma.TaskRunWaitpointGetPayload<T>[];
   }
 
@@ -2267,14 +2439,15 @@ export class PostgresRunStore implements RunStore {
     if (!row) {
       return row;
     }
-    await this.#hydrateDedicatedRelations(client, row, requested, spec);
+    await this.#hydrateDedicatedRelations(client, [row], requested, spec);
     return row;
   }
 
-  // Hydrate each requested dedicated-schema relation key onto `row` in place, honoring the caller's sub-select.
+  // Hydrate each requested dedicated-schema relation key onto EVERY row in `rows` in ONE grouped
+  // pass per key (never one query per row), honoring the caller's sub-select.
   async #hydrateDedicatedRelations(
     client: RunOpsCapableClient,
-    row: Record<string, unknown>,
+    rows: Record<string, unknown>[],
     requested: Record<string, SubProjection>,
     spec: DedicatedRelationSpec
   ): Promise<void> {
@@ -2284,7 +2457,10 @@ export class PostgresRunStore implements RunStore {
         continue;
       }
       const subArgs = requested[key];
-      row[key] = await hydrator(client, row, projectionOf(subArgs), this);
+      const byParentId = await hydrator(client, rows, projectionOf(subArgs), this);
+      for (const row of rows) {
+        row[key] = byParentId.get(row.id as string);
+      }
     }
   }
 
diff --git a/internal-packages/run-store/src/runOpsStore.groupedReads.test.ts b/internal-packages/run-store/src/runOpsStore.groupedReads.test.ts
new file mode 100644
index 0000000000..4b2230bec0
--- /dev/null
+++ b/internal-packages/run-store/src/runOpsStore.groupedReads.test.ts
@@ -0,0 +1,392 @@
+// RED→GREEN for the grouped-read primitive `RoutingRunStore.findRunsByIds`.
+//
+// Today, callers that need N runs by id do `Promise.all(ids.map(id => readThroughRun(id)))`, which
+// fans out to `findRun` PER ID — each one either a direct `taskRun.findFirst` on the owning store, or
+// (for an unclassifiable id) a NEW-then-LEGACY probe. For N ids that is O(N) round trips.
+//
+// `findRunsByIds` is the grouped replacement: it reuses the router's existing bounded id-set
+// machinery (`#findRunsByIdSet` via `findRuns`), which queries NEW for the WHOLE id set in one
+// `findMany`, then probes LEGACY in one more `findMany` only for the ids NEW missed. So for any N
+// (spread across both stores), the call count is CONSTANT (one grouped `findMany` per store queried),
+// never N `findFirst` calls.
+//
+// `heteroRunOpsPostgresTest` gives the REAL split topology: prisma17 = dedicated subset schema
+// (#new), prisma14 = full legacy schema on a SEPARATE physical PG container (#legacy). The counting
+// proxy wraps each REAL client's `taskRun` delegate to tally `findFirst`/`findMany` calls while
+// delegating every call to the real client — the DB still runs the query; this is instrumentation,
+// not a mock.
+
+import { heteroRunOpsPostgresTest } from "@internal/testcontainers";
+import type { PrismaClient } from "@trigger.dev/database";
+import type { RunOpsPrismaClient } from "@internal/run-ops-database";
+import { describe, expect } from "vitest";
+import { PostgresRunStore } from "./PostgresRunStore.js";
+import { RoutingRunStore } from "./runOpsStore.js";
+
+type AnyClient = PrismaClient | RunOpsPrismaClient;
+
+// ownerEngine classifies a 26-char body with version "1" at index 25 (and a valid base32hex/region
+// char elsewhere) as NEW; anything else (including any 25-char id, regardless of content) as LEGACY.
+// The distinguishing prefix varies by `n` so multiple ids in one test stay unique.
+const CUID_25 = (n: number) => `c${String(n).padStart(2, "0")}`.padEnd(25, "c");
+const NEW_ID_26 = (n: number) => `${String(n).padStart(2, "0")}${"k".repeat(22)}01`;
+
+type CallCounts = { findMany: number; findFirst: number };
+
+// Wrap a REAL client's `taskRun` delegate to tally `findFirst`/`findMany` invocations, delegating
+// every call unchanged to the real client (the DB still runs the query — pure instrumentation).
+function countingClient<C extends AnyClient>(real: C): { client: C; counts: CallCounts } {
+  const counts: CallCounts = { findMany: 0, findFirst: 0 };
+  const countingTaskRun = new Proxy((real as any).taskRun, {
+    get(target, prop) {
+      if (prop === "findMany" || prop === "findFirst") {
+        counts[prop as "findMany" | "findFirst"]++;
+      }
+      return (target as any)[prop];
+    },
+  });
+  const client = new Proxy(real, {
+    get(target, prop) {
+      if (prop === "taskRun") {
+        return countingTaskRun;
+      }
+      return (target as any)[prop];
+    },
+  }) as C;
+  return { client, counts };
+}
+
+async function seedEnvironmentLegacy(prisma: PrismaClient, suffix: string) {
+  const organization = await prisma.organization.create({
+    data: { title: `Org ${suffix}`, slug: `org-${suffix}` },
+  });
+  const project = await prisma.project.create({
+    data: {
+      name: `Project ${suffix}`,
+      slug: `project-${suffix}`,
+      externalRef: `proj_${suffix}`,
+      organizationId: organization.id,
+    },
+  });
+  const environment = await prisma.runtimeEnvironment.create({
+    data: {
+      type: "DEVELOPMENT",
+      slug: "dev",
+      projectId: project.id,
+      organizationId: organization.id,
+      apiKey: `tr_dev_${suffix}`,
+      pkApiKey: `pk_dev_${suffix}`,
+      shortcode: `short_${suffix}`,
+    },
+  });
+  return { organization, project, environment };
+}
+
+function seedEnvironmentDedicated(suffix: string) {
+  return {
+    organization: { id: `org_${suffix}` },
+    project: { id: `proj_${suffix}` },
+    environment: { id: `env_${suffix}` },
+  };
+}
+
+function taskRunData(opts: {
+  id: string;
+  friendlyId: string;
+  organizationId: string;
+  projectId: string;
+  runtimeEnvironmentId: string;
+}) {
+  return {
+    id: opts.id,
+    engine: "V2" as const,
+    status: "PENDING" as const,
+    friendlyId: opts.friendlyId,
+    runtimeEnvironmentId: opts.runtimeEnvironmentId,
+    environmentType: "DEVELOPMENT" as const,
+    organizationId: opts.organizationId,
+    projectId: opts.projectId,
+    taskIdentifier: "my-task",
+    payload: "{}",
+    payloadType: "application/json",
+    traceContext: {},
+    traceId: `trace_${opts.id}`,
+    spanId: `span_${opts.id}`,
+    queue: "task/my-task",
+    isTest: false,
+    taskEventStore: "taskEvent",
+    depth: 0,
+  };
+}
+
+describe("RoutingRunStore.findRunsByIds — grouped, residency-partitioned read of a run id set", () => {
+  heteroRunOpsPostgresTest(
+    "returns all N rows with a CONSTANT number of grouped findMany calls (never per-id findFirst)",
+    async ({ prisma14, prisma17 }) => {
+      const legacyCounting = countingClient(prisma14);
+      const newCounting = countingClient(prisma17);
+
+      const legacyStore = new PostgresRunStore({
+        prisma: legacyCounting.client,
+        readOnlyPrisma: legacyCounting.client,
+        schemaVariant: "legacy",
+      });
+      const newStore = new PostgresRunStore({
+        prisma: newCounting.client as never,
+        readOnlyPrisma: newCounting.client as never,
+        schemaVariant: "dedicated",
+      });
+      const router = new RoutingRunStore({ new: newStore, legacy: legacyStore });
+
+      // Seed 2 LEGACY-resident (cuid) runs + 2 NEW-resident (run-ops id) runs — ids spread across
+      // both stores.
+      const legEnv = await seedEnvironmentLegacy(prisma14, "grp_leg");
+      const newEnv = seedEnvironmentDedicated("grp_new");
+
+      const legacyIds = [`run_${CUID_25(1)}`, `run_${CUID_25(2)}`];
+      const newIds = [`run_${NEW_ID_26(1)}`, `run_${NEW_ID_26(2)}`];
+
+      for (const [i, id] of legacyIds.entries()) {
+        await prisma14.taskRun.create({
+          data: taskRunData({
+            id,
+            friendlyId: `run_grp_leg_${i}`,
+            organizationId: legEnv.organization.id,
+            projectId: legEnv.project.id,
+            runtimeEnvironmentId: legEnv.environment.id,
+          }),
+        });
+      }
+      for (const [i, id] of newIds.entries()) {
+        await prisma17.taskRun.create({
+          data: taskRunData({
+            id,
+            friendlyId: `run_grp_new_${i}`,
+            organizationId: newEnv.organization.id,
+            projectId: newEnv.project.id,
+            runtimeEnvironmentId: newEnv.environment.id,
+          }),
+        });
+      }
+
+      const allIds = [...legacyIds, ...newIds];
+
+      // Reset counters after seeding (seeding uses `prisma.taskRun.create`, not find*).
+      legacyCounting.counts.findMany = 0;
+      legacyCounting.counts.findFirst = 0;
+      newCounting.counts.findMany = 0;
+      newCounting.counts.findFirst = 0;
+
+      const result = await router.findRunsByIds(allIds, {
+        select: { friendlyId: true },
+      });
+
+      // All N rows returned, keyed by id.
+      expect(result.size).toBe(4);
+      for (const id of allIds) {
+        expect(result.has(id)).toBe(true);
+      }
+      expect(result.get(legacyIds[0])?.friendlyId).toBe("run_grp_leg_0");
+      expect(result.get(newIds[0])?.friendlyId).toBe("run_grp_new_0");
+
+      // The select omitted `id`; the id we force-inject for keying must not leak into the value.
+      expect("id" in (result.get(legacyIds[0]) as object)).toBe(false);
+      expect("id" in (result.get(newIds[0]) as object)).toBe(false);
+
+      // GROUPED: exactly one findMany call per store queried (NEW always queried for the whole
+      // set; LEGACY queried once more for the misses) — never N per-id findFirst calls.
+      expect(newCounting.counts.findMany).toBe(1);
+      expect(legacyCounting.counts.findMany).toBe(1);
+      expect(newCounting.counts.findFirst).toBe(0);
+      expect(legacyCounting.counts.findFirst).toBe(0);
+    }
+  );
+});
+
+describe("RoutingRunStore.findManyTaskRunWaitpoints — grouped taskRun hydration", () => {
+  heteroRunOpsPostgresTest(
+    "hydrates N edges' `taskRun` with a CONSTANT number of grouped findMany calls (never per-edge findFirst)",
+    async ({ prisma14, prisma17 }) => {
+      const legacyCounting = countingClient(prisma14);
+      const newCounting = countingClient(prisma17);
+
+      const legacyStore = new PostgresRunStore({
+        prisma: legacyCounting.client,
+        readOnlyPrisma: legacyCounting.client,
+        schemaVariant: "legacy",
+      });
+      const newStore = new PostgresRunStore({
+        prisma: newCounting.client as never,
+        readOnlyPrisma: newCounting.client as never,
+        schemaVariant: "dedicated",
+      });
+      const router = new RoutingRunStore({ new: newStore, legacy: legacyStore });
+
+      const legEnv = await seedEnvironmentLegacy(prisma14, "edge_leg");
+      const newEnv = seedEnvironmentDedicated("edge_new");
+
+      const legacyRunIds = [`run_${CUID_25(11)}`, `run_${CUID_25(12)}`];
+      const newRunIds = [`run_${NEW_ID_26(11)}`, `run_${NEW_ID_26(12)}`];
+      for (const [i, id] of legacyRunIds.entries()) {
+        await prisma14.taskRun.create({
+          data: taskRunData({
+            id,
+            friendlyId: `run_edge_leg_${i}`,
+            organizationId: legEnv.organization.id,
+            projectId: legEnv.project.id,
+            runtimeEnvironmentId: legEnv.environment.id,
+          }),
+        });
+      }
+      for (const [i, id] of newRunIds.entries()) {
+        await prisma17.taskRun.create({
+          data: taskRunData({
+            id,
+            friendlyId: `run_edge_new_${i}`,
+            organizationId: newEnv.organization.id,
+            projectId: newEnv.project.id,
+            runtimeEnvironmentId: newEnv.environment.id,
+          }),
+        });
+      }
+
+      // Block edges are FK-free on the dedicated (#new) subset schema, so they can point at a run on
+      // EITHER DB — create one edge per run, all on #new.
+      const allRunIds = [...legacyRunIds, ...newRunIds];
+      const edgeIds: string[] = [];
+      for (const runId of allRunIds) {
+        const edge = await prisma17.taskRunWaitpoint.create({
+          data: {
+            taskRunId: runId,
+            waitpointId: `wp_${runId}`,
+            projectId: newEnv.project.id,
+          },
+        });
+        edgeIds.push(edge.id);
+      }
+
+      legacyCounting.counts.findMany = 0;
+      legacyCounting.counts.findFirst = 0;
+      newCounting.counts.findMany = 0;
+      newCounting.counts.findFirst = 0;
+
+      const rows = await router.findManyTaskRunWaitpoints({
+        where: { id: { in: edgeIds } },
+        select: {
+          id: true,
+          taskRunId: true,
+          taskRun: { select: { id: true, friendlyId: true } },
+        },
+      });
+
+      expect(rows).toHaveLength(4);
+      const byRunId = new Map(rows.map((r) => [r.taskRunId, r.taskRun]));
+      expect((byRunId.get(legacyRunIds[0]) as any)?.friendlyId).toBe("run_edge_leg_0");
+      expect((byRunId.get(newRunIds[0]) as any)?.friendlyId).toBe("run_edge_new_0");
+
+      // GROUPED: one findMany per store queried for the WHOLE edge set, never one findFirst per edge.
+      expect(newCounting.counts.findMany).toBe(1);
+      expect(legacyCounting.counts.findMany).toBe(1);
+      expect(newCounting.counts.findFirst).toBe(0);
+      expect(legacyCounting.counts.findFirst).toBe(0);
+    }
+  );
+});
+
+describe("RoutingRunStore.findWaitpoint connectedRuns — grouped, order-preserving hydration", () => {
+  heteroRunOpsPostgresTest(
+    "hydrates N connectedRuns with a CONSTANT number of grouped findMany calls, in the join's own order",
+    async ({ prisma14, prisma17 }) => {
+      const legacyCounting = countingClient(prisma14);
+      const newCounting = countingClient(prisma17);
+
+      const legacyStore = new PostgresRunStore({
+        prisma: legacyCounting.client,
+        readOnlyPrisma: legacyCounting.client,
+        schemaVariant: "legacy",
+      });
+      const newStore = new PostgresRunStore({
+        prisma: newCounting.client as never,
+        readOnlyPrisma: newCounting.client as never,
+        schemaVariant: "dedicated",
+      });
+      const router = new RoutingRunStore({ new: newStore, legacy: legacyStore });
+
+      const legEnv = await seedEnvironmentLegacy(prisma14, "conn_leg");
+      const newEnv = seedEnvironmentDedicated("conn_new");
+      const waitpointId = `waitpoint_${CUID_25(20)}`;
+      await prisma14.waitpoint.create({
+        data: {
+          id: waitpointId,
+          friendlyId: "wp_conn",
+          type: "MANUAL",
+          status: "PENDING",
+          idempotencyKey: `idem_${waitpointId}`,
+          userProvidedIdempotencyKey: false,
+          projectId: legEnv.project.id,
+          environmentId: legEnv.environment.id,
+        },
+      });
+
+      const legacyRunIds = [`run_${CUID_25(21)}`, `run_${CUID_25(22)}`];
+      const newRunIds = [`run_${NEW_ID_26(21)}`, `run_${NEW_ID_26(22)}`];
+      for (const [i, id] of legacyRunIds.entries()) {
+        await prisma14.taskRun.create({
+          data: taskRunData({
+            id,
+            friendlyId: `run_conn_leg_${i}`,
+            organizationId: legEnv.organization.id,
+            projectId: legEnv.project.id,
+            runtimeEnvironmentId: legEnv.environment.id,
+          }),
+        });
+        await router.blockRunWithWaitpointEdges({
+          runId: id,
+          waitpointIds: [waitpointId],
+          projectId: legEnv.project.id,
+        });
+      }
+      for (const [i, id] of newRunIds.entries()) {
+        await prisma17.taskRun.create({
+          data: taskRunData({
+            id,
+            friendlyId: `run_conn_new_${i}`,
+            organizationId: newEnv.organization.id,
+            projectId: newEnv.project.id,
+            runtimeEnvironmentId: newEnv.environment.id,
+          }),
+        });
+        await router.blockRunWithWaitpointEdges({
+          runId: id,
+          waitpointIds: [waitpointId],
+          projectId: newEnv.project.id,
+        });
+      }
+
+      // The order the connection join itself returns, independent of any assumption about Postgres's
+      // internal row order — the fix must preserve exactly THIS order, not resort by residency/leg.
+      const expectedOrder = await router.findWaitpointConnectedRunIds(waitpointId);
+      expect(expectedOrder).toHaveLength(4);
+
+      legacyCounting.counts.findMany = 0;
+      legacyCounting.counts.findFirst = 0;
+      newCounting.counts.findMany = 0;
+      newCounting.counts.findFirst = 0;
+
+      const waitpoint = (await router.findWaitpoint({
+        where: { id: waitpointId },
+        include: { connectedRuns: { select: { id: true, friendlyId: true } } },
+      })) as { connectedRuns: { id: string; friendlyId: string }[] } | null;
+
+      const connected = waitpoint?.connectedRuns ?? [];
+      expect(connected).toHaveLength(4);
+      expect(connected.map((r) => r.id)).toEqual(expectedOrder);
+
+      // GROUPED: one findMany per store for the WHOLE connected-run set, never one findFirst per run.
+      expect(newCounting.counts.findMany).toBe(1);
+      expect(legacyCounting.counts.findMany).toBe(1);
+      expect(newCounting.counts.findFirst).toBe(0);
+      expect(legacyCounting.counts.findFirst).toBe(0);
+    }
+  );
+});
diff --git a/internal-packages/run-store/src/runOpsStore.residencyMismatchFallback.test.ts b/internal-packages/run-store/src/runOpsStore.residencyMismatchFallback.test.ts
new file mode 100644
index 0000000000..8897c29566
--- /dev/null
+++ b/internal-packages/run-store/src/runOpsStore.residencyMismatchFallback.test.ts
@@ -0,0 +1,296 @@
+// RED→GREEN lock for RoutingRunStore.findRun's ON-MISS FAN-OUT for a CLASSIFIABLE id.
+//
+// THE BUG: findRun for a classifiable id routed to the SINGLE owning store (by id-shape
+// classification) and returned whatever it gave — no on-miss fallback. When a run's PHYSICAL
+// residency does not match its id-shape classification (e.g. a pre-#4154 27-char base62 run that
+// lives on the NEW store but now classifies LEGACY), findRun routed to the wrong store, missed,
+// and returned null → a spurious 404 — even though the run is physically present on the OTHER DB
+// (and runs.list surfaces it). The unclassifiable path already fanned out NEW→LEGACY; this makes
+// the classifiable path equally robust.
+//
+// Uses the REAL two-physical-DB split (heteroRunOpsPostgresTest: prisma14 = full/legacy on PG14,
+// prisma17 = dedicated run-ops subset on PG17). NEVER mocked. The residency/classification MISMATCH
+// is simulated deterministically by injecting a custom `classify` fn into the RoutingRunStore
+// constructor — the physical row is written to the NEW store while `classify` reports its id LEGACY.
+
+import { heteroRunOpsPostgresTest } from "@internal/testcontainers";
+import { ownerEngine, type Residency } from "@trigger.dev/core/v3/isomorphic";
+import type { PrismaClient } from "@trigger.dev/database";
+import type { RunOpsPrismaClient } from "@internal/run-ops-database";
+import { describe, expect } from "vitest";
+import { PostgresRunStore } from "./PostgresRunStore.js";
+import { RoutingRunStore } from "./runOpsStore.js";
+import type { CreateRunInput, RunStore } from "./types.js";
+
+// ownerEngine classifies by internal-id LENGTH/version char: 25 chars → cuid → LEGACY,
+// a v1 body (version "1" at index 25) → run-ops id → NEW.
+function cuidLegacy(seed: string): string {
+  return (seed + "c".repeat(25)).slice(0, 25);
+}
+function runOpsNew(seed: string): string {
+  return (seed.replace(/[^0-9a-v]/g, "0") + "k".repeat(24)).slice(0, 24) + "01";
+}
+
+function makeDedicatedStore(prisma17: RunOpsPrismaClient) {
+  return new PostgresRunStore({
+    prisma: prisma17 as never,
+    readOnlyPrisma: prisma17 as never,
+    schemaVariant: "dedicated",
+  });
+}
+
+function makeLegacyStore(prisma14: PrismaClient) {
+  return new PostgresRunStore({
+    prisma: prisma14,
+    readOnlyPrisma: prisma14,
+    schemaVariant: "legacy",
+  });
+}
+
+// Wrap a real store so findRun/findRunOnPrimary calls are COUNTED while every method still delegates
+// to the REAL PostgresRunStore (this is instrumentation, not a behavior mock — the underlying reads,
+// writes, getters all run for real). Lets us assert the FAST PATH does not touch the other store.
+function countingReads(
+  inner: RunStore,
+  counts: { findRun: number; findRunOnPrimary: number }
+): RunStore {
+  return new Proxy(inner, {
+    get(target, prop) {
+      // Read via target[prop] so getters (e.g. primaryReadClient) run with `this` = the real store.
+      const value = (target as unknown as Record<string | symbol, unknown>)[prop];
+      if (typeof value !== "function") return value;
+      if (prop === "findRun" || prop === "findRunOnPrimary") {
+        return (...args: unknown[]) => {
+          counts[prop as "findRun" | "findRunOnPrimary"] += 1;
+          return (value as (...a: unknown[]) => unknown).apply(target, args);
+        };
+      }
+      return (value as (...a: unknown[]) => unknown).bind(target);
+    },
+  }) as unknown as RunStore;
+}
+
+async function seedLegacyEnvironment(prisma14: PrismaClient, suffix: string) {
+  const organization = await prisma14.organization.create({
+    data: { title: `Org ${suffix}`, slug: `org-${suffix}` },
+  });
+  const project = await prisma14.project.create({
+    data: {
+      name: `Project ${suffix}`,
+      slug: `project-${suffix}`,
+      externalRef: `proj_${suffix}`,
+      organizationId: organization.id,
+    },
+  });
+  const environment = await prisma14.runtimeEnvironment.create({
+    data: {
+      type: "DEVELOPMENT",
+      slug: "dev",
+      projectId: project.id,
+      organizationId: organization.id,
+      apiKey: `tr_dev_${suffix}`,
+      pkApiKey: `pk_dev_${suffix}`,
+      shortcode: `short_${suffix}`,
+    },
+  });
+  return {
+    organizationId: organization.id,
+    projectId: project.id,
+    runtimeEnvironmentId: environment.id,
+    environmentId: environment.id,
+  };
+}
+
+function buildCreateRunInput(params: {
+  runId: string;
+  friendlyId: string;
+  organizationId: string;
+  projectId: string;
+  runtimeEnvironmentId: string;
+}): CreateRunInput {
+  return {
+    data: {
+      id: params.runId,
+      engine: "V2",
+      status: "PENDING",
+      friendlyId: params.friendlyId,
+      runtimeEnvironmentId: params.runtimeEnvironmentId,
+      environmentType: "DEVELOPMENT",
+      organizationId: params.organizationId,
+      projectId: params.projectId,
+      taskIdentifier: "my-task",
+      payload: "{}",
+      payloadType: "application/json",
+      traceContext: {},
+      traceId: `trace_${params.runId}`,
+      spanId: `span_${params.runId}`,
+      queue: "task/my-task",
+      isTest: false,
+      taskEventStore: "taskEvent",
+      depth: 0,
+    },
+    snapshot: {
+      engine: "V2",
+      executionStatus: "RUN_CREATED",
+      description: "Run was created",
+      runStatus: "PENDING",
+      environmentId: params.runtimeEnvironmentId,
+      environmentType: "DEVELOPMENT",
+      projectId: params.projectId,
+      organizationId: params.organizationId,
+    },
+  };
+}
+
+// Insert a TaskRun row DIRECTLY onto the NEW (dedicated) store, bypassing routing, so we can force a
+// residency/classification MISMATCH: the row is physically on #new while `classify` calls its id LEGACY.
+async function insertRunOnNewStore(
+  prisma17: RunOpsPrismaClient,
+  params: {
+    runId: string;
+    friendlyId: string;
+    environmentId: string;
+    organizationId: string;
+    projectId: string;
+  }
+) {
+  await prisma17.taskRun.create({
+    data: {
+      id: params.runId,
+      engine: "V2",
+      status: "PENDING",
+      friendlyId: params.friendlyId,
+      runtimeEnvironmentId: params.environmentId,
+      environmentType: "DEVELOPMENT",
+      organizationId: params.organizationId,
+      projectId: params.projectId,
+      taskIdentifier: "my-task",
+      payload: "{}",
+      payloadType: "application/json",
+      traceContext: {},
+      traceId: `trace_${params.runId}`,
+      spanId: `span_${params.runId}`,
+      queue: "task/my-task",
+      isTest: false,
+      taskEventStore: "taskEvent",
+      depth: 0,
+    },
+  });
+}
+
+describe("RoutingRunStore.findRun — on-miss fan-out for a classifiable id (residency ≠ classification)", () => {
+  // ── THE BUG: a run physically on #new whose id classifies LEGACY must still be found ──
+  // Without the on-miss fallback, findRun routes to #legacy (per classification), misses, returns null.
+  heteroRunOpsPostgresTest(
+    "returns a #new-resident run whose id classifies LEGACY (owning-store miss → other-store fallback)",
+    async ({ prisma14, prisma17 }) => {
+      const env = await seedLegacyEnvironment(prisma14, "mm1");
+      const newStore = makeDedicatedStore(prisma17);
+      const legacyStore = makeLegacyStore(prisma14);
+
+      // A run-ops-shaped id (so ownerEngine would say NEW), but we FORCE classify → LEGACY to model
+      // a residency/classification mismatch: physically on #new, classified LEGACY.
+      const mismatchId = runOpsNew("mm1");
+      const classify = (id: string): Residency => (id === mismatchId ? "LEGACY" : ownerEngine(id));
+      const router = new RoutingRunStore({ new: newStore, legacy: legacyStore, classify });
+
+      await insertRunOnNewStore(prisma17, {
+        runId: mismatchId,
+        friendlyId: "run_mm1",
+        environmentId: env.environmentId,
+        organizationId: env.organizationId,
+        projectId: env.projectId,
+      });
+
+      // Physical residency sanity: on #new only.
+      expect(await prisma17.taskRun.findUnique({ where: { id: mismatchId } })).not.toBeNull();
+      expect(await prisma14.taskRun.findUnique({ where: { id: mismatchId } })).toBeNull();
+
+      // classify → LEGACY routes to #legacy (miss); the fix falls back to #new and finds the run.
+      const byId = (await router.findRun({ id: mismatchId }, { select: { id: true } })) as Record<
+        string,
+        unknown
+      > | null;
+      expect(byId?.id).toBe(mismatchId);
+
+      // Same on the read-your-writes primary variant (a caller-passed writer → findRunOnPrimary).
+      const byIdPrimary = (await router.findRun(
+        { id: mismatchId },
+        { select: { id: true } },
+        prisma14
+      )) as Record<string, unknown> | null;
+      expect(byIdPrimary?.id).toBe(mismatchId);
+    }
+  );
+
+  // ── FAST PATH: a run found in its CLASSIFIED store is a SINGLE read (no second-store probe) ──
+  heteroRunOpsPostgresTest(
+    "does NOT read the other store when the classified (owning) store hits",
+    async ({ prisma14, prisma17 }) => {
+      const env = await seedLegacyEnvironment(prisma14, "mm2");
+
+      // NEW-resident run-ops-id run: owning store = #new. Wrap #legacy to catch any stray probe.
+      const newCounts = { findRun: 0, findRunOnPrimary: 0 };
+      const legacyCounts = { findRun: 0, findRunOnPrimary: 0 };
+      const newStore = countingReads(makeDedicatedStore(prisma17), newCounts);
+      const legacyStore = countingReads(makeLegacyStore(prisma14), legacyCounts);
+      const router = new RoutingRunStore({ new: newStore, legacy: legacyStore });
+
+      const newId = runOpsNew("mm2n"); // classifies NEW
+      await router.createRun(
+        buildCreateRunInput({
+          runId: newId,
+          friendlyId: "run_mm2_new",
+          organizationId: env.organizationId,
+          projectId: env.projectId,
+          runtimeEnvironmentId: env.runtimeEnvironmentId,
+        })
+      );
+
+      const hit = (await router.findRun({ id: newId }, { select: { id: true } })) as Record<
+        string,
+        unknown
+      > | null;
+      expect(hit?.id).toBe(newId);
+      // Owning store read exactly once; the other store NOT touched (fast path preserved).
+      expect(newCounts.findRun).toBe(1);
+      expect(legacyCounts.findRun).toBe(0);
+      expect(legacyCounts.findRunOnPrimary).toBe(0);
+
+      // Symmetric: a cuid run whose owning store is #legacy must not probe #new on a hit.
+      const legacyId = cuidLegacy("mm2l"); // classifies LEGACY
+      await router.createRun(
+        buildCreateRunInput({
+          runId: legacyId,
+          friendlyId: "run_mm2_legacy",
+          organizationId: env.organizationId,
+          projectId: env.projectId,
+          runtimeEnvironmentId: env.runtimeEnvironmentId,
+        })
+      );
+      newCounts.findRun = 0;
+      legacyCounts.findRun = 0;
+
+      const hitLegacy = (await router.findRun(
+        { id: legacyId },
+        { select: { id: true } }
+      )) as Record<string, unknown> | null;
+      expect(hitLegacy?.id).toBe(legacyId);
+      expect(legacyCounts.findRun).toBe(1);
+      expect(newCounts.findRun).toBe(0);
+    }
+  );
+
+  // ── A genuine miss on BOTH stores still returns null (fan-out exhausted) ──
+  heteroRunOpsPostgresTest(
+    "returns null when the run is on neither store",
+    async ({ prisma14, prisma17 }) => {
+      const newStore = makeDedicatedStore(prisma17);
+      const legacyStore = makeLegacyStore(prisma14);
+      const router = new RoutingRunStore({ new: newStore, legacy: legacyStore });
+      expect(
+        await router.findRun({ id: cuidLegacy("ghost") }, { select: { id: true } })
+      ).toBeNull();
+    }
+  );
+});
diff --git a/internal-packages/run-store/src/runOpsStore.ts b/internal-packages/run-store/src/runOpsStore.ts
index 27cab57d1a..ec0decce15 100644
--- a/internal-packages/run-store/src/runOpsStore.ts
+++ b/internal-packages/run-store/src/runOpsStore.ts
@@ -27,6 +27,7 @@ import type {
   WaitpointColocationOptions,
 } from "./types.js";
 import { isReadReplicaClient } from "./readReplicaClient.js";
+import { CONNECTED_RUNS_LIMIT } from "./PostgresRunStore.js";
 
 /**
  * Run-ops routing substrate for the TaskRun-core method group. Implements {@link RunStore}
@@ -238,10 +239,9 @@ export class RoutingRunStore implements RunStore {
     const onPrimary = readYourWrites(argsOrClient, _client);
     const id = idFromWhere(where);
     if (id !== undefined) {
-      // Residency-classifiable (id/friendlyId): route to the owning store.
-      const store = this.#routeOrNew(id);
-      const method = onPrimary ? "findRunOnPrimary" : "findRun";
-      return (store[method] as (...rest: unknown[]) => Promise<unknown>)(where, args);
+      // Residency-classifiable (id/friendlyId): route to the owning store, then fall back to the
+      // OTHER store on a miss.
+      return this.#findRunRouted(id, where, args, onPrimary);
     }
     // Unclassifiable where (e.g. spanId, idempotencyKey): the run may live on either DB,
     // so fan out NEW-first then LEGACY rather than defaulting to NEW — defaulting silently
@@ -249,6 +249,31 @@ export class RoutingRunStore implements RunStore {
     return this.#findRunUnrouted(where, args, onPrimary);
   }
 
+  // A classifiable id names its OWNING store by id-shape, but physical residency can diverge from
+  // classification (a pre-#4154 base62 run lives on #new yet classifies LEGACY). Read the owning
+  // store first — a hit is a SINGLE read (the fast path) — then, ONLY on a miss, probe the OTHER
+  // store before returning null, so a run whose residency ≠ its id-shape is found rather than 404'd.
+  // Both legs run the SAME index-covered TaskRun lookup; the fan-out cost is paid only on the (rare)
+  // miss. Mirrors #findRunUnrouted's shape but keyed on the classified owner.
+  async #findRunRouted(
+    id: string,
+    where: Prisma.TaskRunWhereInput,
+    args: unknown,
+    onPrimary: boolean
+  ): Promise<unknown> {
+    const method = onPrimary ? "findRunOnPrimary" : "findRun";
+    const owning = this.#routeOrNew(id);
+    const fromOwning = await (owning[method] as (...rest: unknown[]) => Promise<unknown>)(
+      where,
+      args
+    );
+    if (fromOwning != null) {
+      return fromOwning;
+    }
+    const other = owning === this.#new ? this.#legacy : this.#new;
+    return (other[method] as (...rest: unknown[]) => Promise<unknown>)(where, args);
+  }
+
   async #findRunUnrouted(
     where: Prisma.TaskRunWhereInput,
     args: unknown,
@@ -376,6 +401,62 @@ export class RoutingRunStore implements RunStore {
     return finalizeRows([...byId.values()], args, addedFields);
   }
 
+  // Canonical grouped replacement for `Promise.all(ids.map(id => readThroughRun(id)))`: reuses
+  // `findRuns`'s bounded id-set path (`#findRunsByIdSet`), so NEW is queried once for the whole set
+  // and LEGACY once more only for the misses — never one round trip per id. Returns an id-keyed Map;
+  // missing/duplicate ids are simply absent/collapsed.
+  findRunsByIds<S extends Prisma.TaskRunSelect>(
+    ids: string[],
+    args: { select: S },
+    client?: ReadClient
+  ): Promise<Map<string, Prisma.TaskRunGetPayload<{ select: S }>>>;
+  findRunsByIds<I extends Prisma.TaskRunInclude>(
+    ids: string[],
+    args: { include: I },
+    client?: ReadClient
+  ): Promise<Map<string, Prisma.TaskRunGetPayload<{ include: I }>>>;
+  findRunsByIds(ids: string[], client?: ReadClient): Promise<Map<string, TaskRun>>;
+  async findRunsByIds(
+    ids: string[],
+    argsOrClient?:
+      | { select?: Record<string, unknown>; include?: Record<string, unknown> }
+      | ReadClient,
+    _client?: ReadClient
+  ): Promise<Map<string, unknown>> {
+    if (ids.length === 0) {
+      return new Map();
+    }
+    const args = selectOrIncludeArgs(argsOrClient);
+    // Mirrors `readYourWrites`'s slot recovery: when `argsOrClient` isn't a `{select|include}`
+    // object it may itself BE the client (2-arg call) or be undefined with the client in the
+    // 3rd slot (an explicit `(ids, undefined, client)` call, e.g. from a relation hydrator).
+    const client =
+      args === undefined ? ((argsOrClient as ReadClient | undefined) ?? _client) : _client;
+    // Force `id` into the projection so the map can key off it, even when the caller's select
+    // omits it — `findRuns` would otherwise strip it back out as an added-for-merge-only field.
+    const projected = args?.select
+      ? { select: { ...args.select, id: true } }
+      : args?.include
+        ? { include: args.include }
+        : {};
+    const rows = (await this.findRuns(
+      { where: { id: { in: ids } }, ...projected } as FindRunsArgs,
+      client
+    )) as Record<string, unknown>[];
+    const byId = new Map<string, unknown>();
+    // Strip the id we force-injected for map keying when the caller's select did not ask for it,
+    // so returned values match the declared payload type and never leak an unrequested id.
+    const stripInjectedId = args?.select != null && !("id" in (args.select as object));
+    for (const row of rows) {
+      const key = row.id as string;
+      if (stripInjectedId) {
+        delete row.id;
+      }
+      byId.set(key, row);
+    }
+    return byId;
+  }
+
   // ---------------------------------------------------------------------------
   // TaskRun-core: update-family — route by run id in params
   // ---------------------------------------------------------------------------
@@ -880,7 +961,8 @@ export class RoutingRunStore implements RunStore {
   // Keyed by waitpointId, but the WaitpointRunConnection / CompletedWaitpoint join co-locates with the
   // RUN/snapshot — which can be on the OTHER DB from a cross-DB token — so fan out to BOTH stores and
   // merge. Dedup by value: a token mirrored onto both DBs during drain can carry the same join
-  // row on each leg.
+  // row on each leg. Each sub-store already caps at CONNECTED_RUNS_LIMIT, but a disjoint run set on
+  // each side can still make the union exceed it, so slice again after the merge.
   async findWaitpointConnectedRunIds(waitpointId: string, client?: ReadClient): Promise<string[]> {
     const [fromNew, fromLegacy] = await Promise.all([
       this.#new.findWaitpointConnectedRunIds(
@@ -892,7 +974,7 @@ export class RoutingRunStore implements RunStore {
         RoutingRunStore.#ownPrimary(this.#legacy, client)
       ),
     ]);
-    return uniqueStrings([...fromNew, ...fromLegacy]);
+    return uniqueStrings([...fromNew, ...fromLegacy]).slice(0, CONNECTED_RUNS_LIMIT);
   }
 
   async findWaitpointCompletedSnapshotIds(
@@ -1123,23 +1205,20 @@ export class RoutingRunStore implements RunStore {
   }
 
   // connectedRuns: the WaitpointRunConnection join co-locates with the run, so read the connected run
-  // ids from EACH store, then resolve the TaskRun rows across BOTH DBs (findRun routes by id).
+  // ids from EACH store, then resolve the TaskRun rows in ONE grouped, residency-partitioned read
+  // (`findRunsByIds`) and reorder to match `runIds` (the join's own order).
   async #reresolveConnectedRunsCrossDb(
     waitpointId: string,
     projection: SubProjection,
     client?: ReadClient
   ): Promise<unknown[]> {
     const runIds = await this.findWaitpointConnectedRunIds(waitpointId, client);
-    const findRun = (this.findRun as (...rest: unknown[]) => Promise<unknown>).bind(this);
     const args = projectionAsArgs(projection);
-    const runs: unknown[] = [];
-    for (const runId of runIds) {
-      const run = await findRun({ id: runId }, args, client);
-      if (run != null) {
-        runs.push(run);
-      }
-    }
-    return runs;
+    const findRunsByIds = (
+      this.findRunsByIds as (...rest: unknown[]) => Promise<Map<string, unknown>>
+    ).bind(this);
+    const byId = runIds.length > 0 ? await findRunsByIds(runIds, args, client) : new Map();
+    return runIds.map((id) => byId.get(id)).filter((run) => run != null);
   }
 
   // completedExecutionSnapshots: the CompletedWaitpoint join co-locates with the snapshot/run, so read
@@ -1300,21 +1379,25 @@ export class RoutingRunStore implements RunStore {
     }
   }
 
-  // Resolve each edge's `taskRun` from its scalar `taskRunId` across BOTH stores (findRun routes by
-  // id and falls back NEW→LEGACY). A missing run is left null (display-only callers tolerate it; the
-  // blocked-run resume path keys off `waitpoint`).
+  // Resolve every edge's `taskRun` from its scalar `taskRunId` in ONE grouped, residency-partitioned
+  // read (`findRunsByIds`) rather than one `findRun` per edge. A missing run is left null
+  // (display-only callers tolerate it; the blocked-run resume path keys off `waitpoint`).
   async #hydrateEdgeTaskRunsCrossDb(
     edges: Record<string, unknown>[],
     projection: SubProjection,
     client?: ReadClient
   ): Promise<void> {
-    // Bind to `this`: findRun reaches the private #routeOrNew/#findRunUnrouted members, so an unbound
-    // reference loses `this` and throws on the first private access.
-    const findRun = (this.findRun as (...rest: unknown[]) => Promise<unknown>).bind(this);
+    const ids = uniqueStrings(edges.map((e) => e.taskRunId));
     const args = projectionAsArgs(projection);
+    // Bind to `this`: findRunsByIds reaches private members, so an unbound reference throws.
+    const findRunsByIds = (
+      this.findRunsByIds as (...rest: unknown[]) => Promise<Map<string, unknown>>
+    ).bind(this);
+    const byId =
+      ids.length > 0 ? await findRunsByIds(ids, args, client) : new Map<string, unknown>();
     for (const edge of edges) {
       const id = edge.taskRunId as string | undefined;
-      const run = id ? await findRun({ id }, args, client) : null;
+      const run = id ? byId.get(id) : undefined;
       edge.taskRun = applyEdgeProjection((run as Record<string, unknown>) ?? null, projection);
     }
   }
diff --git a/internal-packages/run-store/src/scheduleSeam.test.ts b/internal-packages/run-store/src/scheduleSeam.test.ts
new file mode 100644
index 0000000000..43c4ce63bf
--- /dev/null
+++ b/internal-packages/run-store/src/scheduleSeam.test.ts
@@ -0,0 +1,306 @@
+// SCHEDULES over the run-ops cutover SEAM.
+//
+// schedule-engine (internal-packages/schedule-engine) has NO residency logic of its own: a cron
+// schedule fires and calls back into `onTriggerScheduledTask` (apps/webapp/app/v3/scheduleEngine.server.ts),
+// which mints the run via the ORDINARY TriggerTaskService -> RunEngine.trigger -> RoutingRunStore.createRun
+// path — the same mint path already exercised by internal-packages/run-engine/src/engine/tests/triggerCreateRouting.test.ts
+// and the `case 1` / `case 1b` findRuns-by-id-set tests in runOpsStore.mixedResidency.test.ts. There is no
+// schedule-specific residency branch to test at the mint step; schedules simply inherit whatever the trigger
+// path already does. Case A below adds exactly ONE small confirming test (using the previously-untested
+// `scheduleId`/`scheduleInstanceId` scalar fields specifically) rather than re-deriving that generic coverage.
+//
+// The one piece of schedule-adjacent logic that genuinely spans the seam and had NO hetero coverage is
+// `rescheduleRun` (RoutingRunStore.rescheduleRun, runOpsStore.ts:617) — the write delegate behind the
+// delayed-run "reschedule" API (apps/webapp/app/v3/services/rescheduleTaskRun.server.ts) and
+// `DelayedRunSystem.rescheduleDelayedRun`. It is a pure `#routeForWrite(runId)` mechanical delegate with
+// no dedicated mixed-residency test anywhere in the existing matrix (runOpsStore.mixedResidency.test.ts
+// covers batch/waitpoint/find methods but not rescheduleRun). Case B below closes that gap.
+//
+// Real two-physical-DB fixture, NO MOCKS: heteroRunOpsPostgresTest (prisma14 = full control-plane/LEGACY
+// schema, prisma17 = RunOpsPrismaClient dedicated NEW-subset schema).
+
+import { heteroRunOpsPostgresTest } from "@internal/testcontainers";
+import type { PrismaClient } from "@trigger.dev/database";
+import type { RunOpsPrismaClient } from "@internal/run-ops-database";
+import { describe, expect } from "vitest";
+import { PostgresRunStore } from "./PostgresRunStore.js";
+import { RoutingRunStore } from "./runOpsStore.js";
+import type { CreateRunInput, RunStoreSchemaVariant } from "./types.js";
+
+type AnyClient = PrismaClient | RunOpsPrismaClient;
+
+// ownerEngine classifies by internal-id LENGTH after stripping a leading `<prefix>_`
+// (runOpsResidency.ts): 25 chars → cuid → LEGACY, a v1 body (version "1" at index 25 of a 26-char
+// body) → run-ops id → NEW. Mirrors the helpers in runOpsStore.mixedResidency.test.ts so ids classify
+// the same way here (the documented ID pitfall: a naive generator misclassifies NEW ids as LEGACY).
+function cuidLegacy(seed: string): string {
+  return (seed + "c".repeat(25)).slice(0, 25); // 25 chars → LEGACY (#legacy / prisma14)
+}
+function runOpsNew(seed: string): string {
+  return (seed.replace(/[^0-9a-v]/g, "0") + "k".repeat(24)).slice(0, 24) + "01"; // 26 chars, version "1" at index 25 → NEW (#new / prisma17)
+}
+
+async function seedEnvironment(
+  prisma: AnyClient,
+  schemaVariant: RunStoreSchemaVariant,
+  suffix: string
+) {
+  if (schemaVariant === "dedicated") {
+    return {
+      organization: { id: `org_${suffix}` },
+      project: { id: `proj_${suffix}` },
+      environment: { id: `env_${suffix}` },
+    };
+  }
+  const organization = await (prisma as PrismaClient).organization.create({
+    data: { title: `Org ${suffix}`, slug: `org-${suffix}` },
+  });
+  const project = await (prisma as PrismaClient).project.create({
+    data: {
+      name: `Project ${suffix}`,
+      slug: `project-${suffix}`,
+      externalRef: `proj_${suffix}`,
+      organizationId: organization.id,
+    },
+  });
+  const environment = await (prisma as PrismaClient).runtimeEnvironment.create({
+    data: {
+      type: "DEVELOPMENT",
+      slug: "dev",
+      projectId: project.id,
+      organizationId: organization.id,
+      apiKey: `tr_dev_${suffix}`,
+      pkApiKey: `pk_dev_${suffix}`,
+      shortcode: `short_${suffix}`,
+    },
+  });
+  return { organization, project, environment };
+}
+
+async function seedSharedEnv(prisma14: PrismaClient, suffix: string) {
+  const legacy = await seedEnvironment(prisma14, "legacy", suffix);
+  return {
+    organizationId: legacy.organization.id,
+    projectId: legacy.project.id,
+    runtimeEnvironmentId: legacy.environment.id,
+    environmentId: legacy.environment.id,
+  };
+}
+
+function buildCreateRunInput(params: {
+  runId: string;
+  friendlyId: string;
+  organizationId: string;
+  projectId: string;
+  runtimeEnvironmentId: string;
+  status?: "PENDING" | "DELAYED";
+  scheduleId?: string;
+  scheduleInstanceId?: string;
+}): CreateRunInput {
+  return {
+    data: {
+      id: params.runId,
+      engine: "V2",
+      status: params.status ?? "PENDING",
+      friendlyId: params.friendlyId,
+      runtimeEnvironmentId: params.runtimeEnvironmentId,
+      environmentType: "DEVELOPMENT",
+      organizationId: params.organizationId,
+      projectId: params.projectId,
+      taskIdentifier: "my-scheduled-task",
+      payload: '{"hello":"world"}',
+      payloadType: "application/json",
+      traceContext: { trace: "ctx" },
+      traceId: `trace_${params.runId}`,
+      spanId: `span_${params.runId}`,
+      runTags: [],
+      queue: "task/my-scheduled-task",
+      isTest: false,
+      taskEventStore: "taskEvent",
+      depth: 0,
+      createdAt: new Date("2024-01-01T00:00:00.000Z"),
+      ...(params.scheduleId && { scheduleId: params.scheduleId }),
+      ...(params.scheduleInstanceId && { scheduleInstanceId: params.scheduleInstanceId }),
+    },
+    snapshot: {
+      engine: "V2",
+      executionStatus: "RUN_CREATED",
+      description: "Run was created",
+      runStatus: params.status ?? "PENDING",
+      environmentId: params.runtimeEnvironmentId,
+      environmentType: "DEVELOPMENT",
+      projectId: params.projectId,
+      organizationId: params.organizationId,
+    },
+  };
+}
+
+function makeDedicatedStore(prisma17: RunOpsPrismaClient) {
+  return new PostgresRunStore({
+    prisma: prisma17 as never,
+    readOnlyPrisma: prisma17 as never,
+    schemaVariant: "dedicated",
+  });
+}
+
+function makeLegacyStore(prisma14: PrismaClient) {
+  return new PostgresRunStore({
+    prisma: prisma14,
+    readOnlyPrisma: prisma14,
+    schemaVariant: "legacy",
+  });
+}
+
+// The REAL production split topology: #new = dedicated subset on prisma17, #legacy = full schema on
+// prisma14.
+function makeSplitRouter(prisma14: PrismaClient, prisma17: RunOpsPrismaClient) {
+  const legacyStore = makeLegacyStore(prisma14);
+  const newStore = makeDedicatedStore(prisma17);
+  return {
+    router: new RoutingRunStore({ new: newStore, legacy: legacyStore }),
+    legacyStore,
+    newStore,
+  };
+}
+
+describe("Schedules over the cutover seam", () => {
+  // ── Case A: a schedule-minted run (scheduleId/scheduleInstanceId set) lands on the correct
+  // physical store under mixed residency, and is found by plain id lookup (the ONLY lookup that
+  // exists — there is no scheduleInstanceId-keyed TaskRun query anywhere in the codebase; the field
+  // is write-only metadata stamped at creation). This confirms schedules have no distinct mint-routing
+  // seam beyond the already-covered generic createRun routing. ──
+  heteroRunOpsPostgresTest(
+    "case A: a schedule-minted run routes to the owning store and resolves by id, for both residencies",
+    async ({ prisma14, prisma17 }) => {
+      const { router } = makeSplitRouter(prisma14, prisma17);
+      const env = await seedSharedEnv(prisma14, "schedA");
+
+      const legacyRun = cuidLegacy("schAl"); // pre-cutover mint shape → #legacy
+      const newRun = runOpsNew("schAn"); // run-ops mint shape → #new
+
+      await router.createRun(
+        buildCreateRunInput({
+          runId: legacyRun,
+          friendlyId: "run_schedA_legacy",
+          scheduleId: "sched_A",
+          scheduleInstanceId: "schedinst_A_legacy",
+          ...env,
+        })
+      );
+      await router.createRun(
+        buildCreateRunInput({
+          runId: newRun,
+          friendlyId: "run_schedA_new",
+          scheduleId: "sched_A",
+          scheduleInstanceId: "schedinst_A_new",
+          ...env,
+        })
+      );
+
+      // Physical residency: each landed on its OWN DB only, with the scheduleInstanceId intact.
+      const onLegacy = await prisma14.taskRun.findUnique({ where: { id: legacyRun } });
+      expect(onLegacy?.scheduleInstanceId).toBe("schedinst_A_legacy");
+      expect(await prisma17.taskRun.findUnique({ where: { id: legacyRun } })).toBeNull();
+
+      const onNew = await prisma17.taskRun.findUnique({ where: { id: newRun } });
+      expect(onNew?.scheduleInstanceId).toBe("schedinst_A_new");
+      expect(await prisma14.taskRun.findUnique({ where: { id: newRun } })).toBeNull();
+
+      // The only lookup a schedule-minted run ever needs (by id) resolves through the router on
+      // BOTH residencies.
+      const foundLegacy = (await router.findRun(
+        { id: legacyRun },
+        { select: { id: true, scheduleInstanceId: true } }
+      )) as Record<string, any> | null;
+      expect(foundLegacy?.id).toBe(legacyRun);
+      expect(foundLegacy?.scheduleInstanceId).toBe("schedinst_A_legacy");
+
+      const foundNew = (await router.findRun(
+        { id: newRun },
+        { select: { id: true, scheduleInstanceId: true } }
+      )) as Record<string, any> | null;
+      expect(foundNew?.id).toBe(newRun);
+      expect(foundNew?.scheduleInstanceId).toBe("schedinst_A_new");
+    }
+  );
+
+  // ── Case B: rescheduleRun (the write delegate behind the delayed-run "reschedule" API and
+  // DelayedRunSystem.rescheduleDelayedRun) routes to the OWNING store for a mixed-residency
+  // population, and does NOT touch the other physical DB. No existing hetero test covers this
+  // write path. ──
+  heteroRunOpsPostgresTest(
+    "case B: rescheduleRun routes the write to the owning store only, for a mixed-residency population",
+    async ({ prisma14, prisma17 }) => {
+      const { router } = makeSplitRouter(prisma14, prisma17);
+      const env = await seedSharedEnv(prisma14, "schedB");
+
+      const legacyRun = cuidLegacy("schBl");
+      const newRun = runOpsNew("schBn");
+
+      await router.createRun(
+        buildCreateRunInput({
+          runId: legacyRun,
+          friendlyId: "run_schedB_legacy",
+          status: "DELAYED",
+          ...env,
+        })
+      );
+      await router.createRun(
+        buildCreateRunInput({
+          runId: newRun,
+          friendlyId: "run_schedB_new",
+          status: "DELAYED",
+          ...env,
+        })
+      );
+
+      const legacyDelayUntil = new Date("2027-05-01T00:00:00.000Z");
+      const newDelayUntil = new Date("2027-06-01T00:00:00.000Z");
+
+      const updatedLegacy = await router.rescheduleRun(legacyRun, {
+        delayUntil: legacyDelayUntil,
+        snapshot: {
+          environmentId: env.environmentId,
+          environmentType: "DEVELOPMENT",
+          projectId: env.projectId,
+          organizationId: env.organizationId,
+        },
+      });
+      const updatedNew = await router.rescheduleRun(newRun, {
+        delayUntil: newDelayUntil,
+        snapshot: {
+          environmentId: env.environmentId,
+          environmentType: "DEVELOPMENT",
+          projectId: env.projectId,
+          organizationId: env.organizationId,
+        },
+      });
+
+      expect(updatedLegacy.id).toBe(legacyRun);
+      expect(updatedLegacy.delayUntil).toEqual(legacyDelayUntil);
+      expect(updatedNew.id).toBe(newRun);
+      expect(updatedNew.delayUntil).toEqual(newDelayUntil);
+
+      // The write landed on the OWNING physical DB only.
+      const legacyRow = await prisma14.taskRun.findUnique({ where: { id: legacyRun } });
+      expect(legacyRow?.delayUntil).toEqual(legacyDelayUntil);
+      const legacySnapshots = await prisma14.taskRunExecutionSnapshot.findMany({
+        where: { runId: legacyRun, executionStatus: "DELAYED" },
+      });
+      expect(legacySnapshots).toHaveLength(1);
+
+      const newRow = await prisma17.taskRun.findUnique({ where: { id: newRun } });
+      expect(newRow?.delayUntil).toEqual(newDelayUntil);
+      const newSnapshots = await prisma17.taskRunExecutionSnapshot.findMany({
+        where: { runId: newRun, executionStatus: "DELAYED" },
+      });
+      expect(newSnapshots).toHaveLength(1);
+
+      // Cross-DB isolation: the OTHER physical DB's row for each run is untouched by the other
+      // reschedule call — neither run exists on the non-owning DB at all, so there is nothing there
+      // to have been (mis)updated.
+      expect(await prisma17.taskRun.findUnique({ where: { id: legacyRun } })).toBeNull();
+      expect(await prisma14.taskRun.findUnique({ where: { id: newRun } })).toBeNull();
+    }
+  );
+});
diff --git a/internal-packages/run-store/src/types.ts b/internal-packages/run-store/src/types.ts
index 1d39498f39..26ccb52aea 100644
--- a/internal-packages/run-store/src/types.ts
+++ b/internal-packages/run-store/src/types.ts
@@ -573,6 +573,21 @@ export interface RunStore {
     client?: ReadClient
   ): Promise<TaskRun[]>;
 
+  // Grouped replacement for `Promise.all(ids.map(id => findRun(id)))`: one round trip for the
+  // whole id batch instead of one per id. Returns an id-keyed Map; missing/duplicate ids are
+  // simply absent/collapsed.
+  findRunsByIds<S extends Prisma.TaskRunSelect>(
+    ids: string[],
+    args: { select: S },
+    client?: ReadClient
+  ): Promise<Map<string, Prisma.TaskRunGetPayload<{ select: S }>>>;
+  findRunsByIds<I extends Prisma.TaskRunInclude>(
+    ids: string[],
+    args: { include: I },
+    client?: ReadClient
+  ): Promise<Map<string, Prisma.TaskRunGetPayload<{ include: I }>>>;
+  findRunsByIds(ids: string[], client?: ReadClient): Promise<Map<string, TaskRun>>;
+
   // --- run-ops persistence ---
   // Snapshots, waitpoints, implicit M:N joins, dependents, attempts and checkpoints. The
   // generic model wrappers are thin generics over the Prisma `*Args` types so include/select