diff --git a/src/server/management/agent-settings-routes.ts b/src/server/management/agent-settings-routes.ts
index d06d25630..3abeb3230 100644
--- a/src/server/management/agent-settings-routes.ts
+++ b/src/server/management/agent-settings-routes.ts
@@ -59,7 +59,7 @@ import { applySystemEnvToggle } from "../system-env";
 
 import { isPlainRecord, parseDebugLogQuery, tokPerSecondResult, unavailableCostReason, costResult, requestLogDto, stripRegistryOnlyStaticHeaders, fetchAllModels, fetchGrokCandidateModels, buildClaudeDesktopState } from "./shared";
 import type { MetricUnavailableReason, TokPerSecondResult, CostEstimateReason, CostResult, MetricSource } from "./shared";
-import { readManagementJsonBody, rethrowManagementBodyTooLarge } from "./body";
+import { readManagementJsonBody, readOptionalManagementJsonBody, rethrowManagementBodyTooLarge } from "./body";
 
 const GROK_APPLY_JOIN_MS = 120_000;
 export const GROK_APPLY_TERMINAL_MS = 10 * 60_000;
@@ -703,21 +703,19 @@ export async function handleAgentSettingsRoutes(ctx: ManagementContext): Promise
       // #859: the CLI delegates here so the registry is built in the serving
       // process. Accept an optional mode; default stays static for back-compat.
       let mode: "static" | "hybrid" | "discovery" = "static";
-      const rawBody = await req.text();
       let parsed: unknown;
-      if (rawBody.trim()) {
-        try {
-          parsed = JSON.parse(rawBody);
-        } catch {
-          return jsonResponse({ error: "invalid JSON body" }, 400);
-        }
-        const requested = (parsed as { mode?: unknown } | null)?.mode;
-        if (requested !== undefined) {
-          if (requested === "static" || requested === "hybrid" || requested === "discovery") {
-            mode = requested;
-          } else {
-            return jsonResponse({ error: "mode must be static, hybrid, or discovery" }, 400);
-          }
+      try {
+        parsed = await readOptionalManagementJsonBody(req);
+      } catch (error) {
+        rethrowManagementBodyTooLarge(error);
+        return jsonResponse({ error: "invalid JSON body" }, 400);
+      }
+      const requested = (parsed as { mode?: unknown } | null)?.mode;
+      if (requested !== undefined) {
+        if (requested === "static" || requested === "hybrid" || requested === "discovery") {
+          mode = requested;
+        } else {
+          return jsonResponse({ error: "mode must be static, hybrid, or discovery" }, 400);
         }
       }
       // #859: a delegated CLI apply carries the profile it just saved — the
@@ -760,6 +758,7 @@ export async function handleAgentSettingsRoutes(ctx: ManagementContext): Promise
       }
       return jsonResponse({ ok: true, saved: true, applied: true, path: result.path, fingerprint: result.fingerprint });
     } catch (error) {
+      rethrowManagementBodyTooLarge(error);
       return jsonResponse({ error: error instanceof Error ? error.message : String(error) }, 400);
     }
   }
diff --git a/src/server/management/body.ts b/src/server/management/body.ts
index e2f4f0d17..5d506c26c 100644
--- a/src/server/management/body.ts
+++ b/src/server/management/body.ts
@@ -11,6 +11,12 @@ export function readManagementJsonBody<T = unknown>(req: Request): Promise<T> {
   return readBoundedJsonRequestBody(req, MANAGEMENT_JSON_BODY_MAX_BYTES) as Promise<T>;
 }
 
+export function readOptionalManagementJsonBody<T = unknown>(req: Request): Promise<T> {
+  return readBoundedJsonRequestBody(req, MANAGEMENT_JSON_BODY_MAX_BYTES, undefined, {
+    emptyBodyFallback: {},
+  }) as Promise<T>;
+}
+
 export function managementBodyTooLargeResponse(
   error: unknown,
   req: Request,
diff --git a/src/server/request-decompress.ts b/src/server/request-decompress.ts
index c3e5bca0a..e318557b1 100644
--- a/src/server/request-decompress.ts
+++ b/src/server/request-decompress.ts
@@ -90,6 +90,7 @@ export async function readBoundedJsonRequestBody(
   req: Request,
   maxBytes: number,
   budget?: TranslatorBudget,
+  options?: { emptyBodyFallback?: unknown },
 ): Promise<unknown> {
   const encoding = req.headers.get("content-encoding");
   const declaredLength = declaredBodyLength(req);
@@ -116,6 +117,9 @@ export async function readBoundedJsonRequestBody(
     releaseDecoded = decoded === raw ? undefined : budget?.observeAcceptedRequestCopy(decoded.byteLength);
     const text = new TextDecoder().decode(decoded);
     releaseText = budget?.observeAcceptedRequestCopy(new TextEncoder().encode(text).byteLength);
+    if (text.trim() === "" && options && "emptyBodyFallback" in options) {
+      return options.emptyBodyFallback;
+    }
     const parsed = JSON.parse(text);
     budget?.observeAcceptedRequestCopy(new TextEncoder().encode(JSON.stringify(parsed)).byteLength);
     return parsed;
diff --git a/tests/claude-management-api.test.ts b/tests/claude-management-api.test.ts
index 4286deeac..283b0325b 100644
--- a/tests/claude-management-api.test.ts
+++ b/tests/claude-management-api.test.ts
@@ -8,6 +8,7 @@ import { startServer } from "../src/server";
 import * as systemEnv from "../src/server/system-env";
 import type { OcxConfig } from "../src/types";
 import { installIsolatedCodexHome, type IsolatedCodexHome } from "./helpers/isolated-codex-home";
+import { MANAGEMENT_JSON_BODY_MAX_BYTES } from "../src/server/management/body";
 
 // Full-suite Windows load: startServer + multi-PUT management flows often exceed bun's
 // default 5s per-test budget (same flake class as 810fa115 / kiro-oauth).
@@ -690,6 +691,14 @@ test("Claude Desktop apply honors the profile in the request body over daemon-st
 test("Claude Desktop apply validates the mode body", async () => {
   const server = startServer(0);
   try {
+    const malformed = await fetch(new URL("/api/claude-desktop/apply", server.url), {
+      method: "POST",
+      headers: { "Content-Type": "application/json" },
+      body: "{",
+    });
+    expect(malformed.status).toBe(400);
+    expect(await malformed.json()).toEqual({ error: "invalid JSON body" });
+
     const bad = await fetch(new URL("/api/claude-desktop/apply", server.url), {
       method: "POST",
       headers: { "Content-Type": "application/json" },
@@ -711,6 +720,22 @@ test("Claude Desktop apply validates the mode body", async () => {
   }
 });
 
+test("Claude Desktop apply rejects a decompressed body over the management limit", async () => {
+  const server = startServer(0);
+  try {
+    const oversized = JSON.stringify({ pad: "x".repeat(MANAGEMENT_JSON_BODY_MAX_BYTES) });
+    const response = await fetch(new URL("/api/claude-desktop/apply", server.url), {
+      method: "POST",
+      headers: { "Content-Type": "application/json", "Content-Encoding": "gzip" },
+      body: Bun.gzipSync(new TextEncoder().encode(oversized)),
+    });
+    expect(response.status).toBe(413);
+    expect(await response.json()).toEqual({ error: "request body too large" });
+  } finally {
+    await server.stop(true);
+  }
+});
+
 test("Claude Desktop PUT rejects invalid JSON profile without mutating saved config", async () => {
   const server = startServer(0);
   try {