diff --git a/ROADMAP.md b/ROADMAP.md
index 971889298..c404d8b8f 100644
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -126,6 +126,7 @@ This strategy ensures rapid iteration while maintaining a clear path to producti
 | CI lint rule rejecting new `z.any()` | 🔴 | Planned — eslint or custom lint rule to block `z.any()` additions |
 | Dispatcher async `getService` bug fix | ✅ | All `getService`/`getObjectQLService` calls in `http-dispatcher.ts` now properly `await` async service factories. Covers `handleAnalytics`, `handleAuth`, `handleStorage`, `handleAutomation`, `handleMetadata`, `handleUi`, `handlePackages`. All 7 framework adapters (Express, Fastify, Hono, Next.js, SvelteKit, NestJS, Nuxt) updated to use `getServiceAsync()` for auth service resolution. |
 | Analytics `getMetadata` → `getMeta` naming fix | ✅ | `handleAnalytics` in `http-dispatcher.ts` called `getMetadata({ request })` which didn't match the `IAnalyticsService` contract (`getMeta(cubeName?: string)`). Renamed to `getMeta()` and aligned call signature. Updated test mocks accordingly. |
+| Unified ID/audit/tenant field naming | ✅ | Eliminated `_id`/`modified_at`/`modified_by`/`space_id` from protocol layer. All protocol code uses `id`, `updated_at`, `updated_by`, `tenant_id` per `SystemFieldName`. Storage-layer (NoSQL driver internals) retains `_id` for MongoDB/Mingo compat. |
 
 ---
 
diff --git a/apps/studio/src/components/ObjectDataForm.tsx b/apps/studio/src/components/ObjectDataForm.tsx
index acc12d118..b3e8cd12a 100644
--- a/apps/studio/src/components/ObjectDataForm.tsx
+++ b/apps/studio/src/components/ObjectDataForm.tsx
@@ -57,7 +57,6 @@ export function ObjectDataForm({ objectApiName, record, onSuccess, onCancel }: O
         
         try {
             const dataToSubmit = { ...formData };
-            delete dataToSubmit._id;
             delete dataToSubmit.id;
             delete dataToSubmit.created_at;
             delete dataToSubmit.updated_at;
@@ -71,8 +70,8 @@ export function ObjectDataForm({ objectApiName, record, onSuccess, onCancel }: O
                 });
             }
 
-            if (record && (record.id || record._id)) {
-                await client.data.update(objectApiName, record.id || record._id, dataToSubmit);
+            if (record && record.id) {
+                await client.data.update(objectApiName, record.id, dataToSubmit);
             } else {
                 await client.data.create(objectApiName, dataToSubmit);
             }
@@ -109,10 +108,10 @@ export function ObjectDataForm({ objectApiName, record, onSuccess, onCancel }: O
 
     const fields = def.fields || {};
     const fieldKeys = Object.keys(fields).filter(k => {
-        return !['created_at', 'updated_at', 'created_by', 'modified_by'].includes(k);
+        return !['created_at', 'updated_at', 'created_by', 'updated_by'].includes(k);
     });
 
-    const isEdit = !!(record && (record.id || record._id));
+    const isEdit = !!(record && record.id);
 
     return (
         <Dialog open={true} onOpenChange={(open) => !open && onCancel()}>
diff --git a/apps/studio/src/components/ObjectDataTable.tsx b/apps/studio/src/components/ObjectDataTable.tsx
index 9d70812ab..8a11aab8c 100644
--- a/apps/studio/src/components/ObjectDataTable.tsx
+++ b/apps/studio/src/components/ObjectDataTable.tsx
@@ -277,7 +277,7 @@ export function ObjectDataTable({ objectApiName, onEdit }: ObjectDataTableProps)
                             {loading && records.length === 0 ? (
                                 <TableSkeleton cols={columns.length} />
                             ) : filteredRecords.map(record => (
-                                <TableRow key={record.id || record._id} className="group">
+                                <TableRow key={record.id} className="group">
                                     {columns.map(col => (
                                         <TableCell key={col.name} className="py-2.5">
                                             <CellValue value={record[col.name]} type={col.type} />
@@ -302,7 +302,7 @@ export function ObjectDataTable({ objectApiName, onEdit }: ObjectDataTableProps)
                                                 </DropdownMenuItem>
                                                 <DropdownMenuSeparator />
                                                 <DropdownMenuItem 
-                                                    onClick={() => handleDelete(record.id || record._id)}
+                                                    onClick={() => handleDelete(record.id)}
                                                     className="text-destructive focus:text-destructive"
                                                 >
                                                     <Trash2 className="mr-2 h-4 w-4" />
diff --git a/apps/studio/src/mocks/createKernel.ts b/apps/studio/src/mocks/createKernel.ts
index df1eb96fb..8c3326c3d 100644
--- a/apps/studio/src/mocks/createKernel.ts
+++ b/apps/studio/src/mocks/createKernel.ts
@@ -65,7 +65,7 @@ export async function createKernel(options: KernelOptions) {
                 if (method === 'create') {
                      const res = await ql.insert(params.object, params.data);
                      const record = { ...params.data, ...res };
-                     return { object: params.object, id: record.id || record._id, record };
+                     return { object: params.object, id: record.id, record };
                 }
                 if (method === 'get') {
                      // Delegate to protocol for proper expand/select support
@@ -74,7 +74,7 @@ export async function createKernel(options: KernelOptions) {
                      }
                      let all = await ql.find(params.object);
                      if (!all) all = [];
-                     const match = all.find((i: any) => i.id === params.id || i._id === params.id);
+                     const match = all.find((i: any) => i.id === params.id);
                      return match ? { object: params.object, id: params.id, record: match } : null;
                 }
                 if (method === 'update') {
@@ -85,7 +85,7 @@ export async function createKernel(options: KernelOptions) {
                          if (all && (all as any).value) all = (all as any).value;
                          if (!all) all = [];
                          
-                         const existing = all.find((i: any) => i.id === params.id || i._id === params.id);
+                         const existing = all.find((i: any) => i.id === params.id);
                          
                          if (!existing) {
                              console.warn(`[BrokerShim] Update failed: Record ${params.id} not found.`);
@@ -183,7 +183,7 @@ export async function createKernel(options: KernelOptions) {
                              : String(queryOptions.select).split(',').map((s: string) => s.trim());
                         
                         all = all.map((item: any) => {
-                            const projected: any = { id: item.id, _id: item._id }; // Always include ID
+                            const projected: any = { id: item.id }; // Always include ID
                             selectFields.forEach((f: string) => {
                                 if (item[f] !== undefined) projected[f] = item[f];
                             });
diff --git a/apps/studio/src/types.ts b/apps/studio/src/types.ts
index a73f76845..fcff8309c 100644
--- a/apps/studio/src/types.ts
+++ b/apps/studio/src/types.ts
@@ -4,8 +4,7 @@
  * Task type definition (todo_task)
  */
 export interface Task {
-  _id: string; // Internal ID
-  id: string; // External ID usually, but here we might get _id or id depending on driver
+  id: string;
   subject: string;
   priority: number;
   is_completed: boolean;
diff --git a/content/docs/guides/standards.mdx b/content/docs/guides/standards.mdx
index e0a1fd282..09df382e0 100644
--- a/content/docs/guides/standards.mdx
+++ b/content/docs/guides/standards.mdx
@@ -545,7 +545,7 @@ describe('Account Object', () => {
 - [ ] All objects use `ObjectSchema.create()`
 - [ ] Field names are `snake_case`
 - [ ] Config keys are `camelCase`
-- [ ] Lookups don't have `_id` suffix
+- [ ] Lookups don't have `_id` suffix (use `id`)
 - [ ] All validations have clear messages
 - [ ] Documentation is up to date
 - [ ] Tests pass
diff --git a/content/docs/protocol/objectql/index.mdx b/content/docs/protocol/objectql/index.mdx
index 3b76fbc76..3eb8a3a68 100644
--- a/content/docs/protocol/objectql/index.mdx
+++ b/content/docs/protocol/objectql/index.mdx
@@ -147,7 +147,7 @@ const query: Query = {
 -- PostgreSQL (with JOIN)
 SELECT c.company_name, c.industry, u.name AS "owner.name"
 FROM customer c
-LEFT JOIN user u ON c.owner_id = u._id
+LEFT JOIN user u ON c.owner_id = u.id
 WHERE c.industry = 'tech' AND c.annual_revenue > 1000000
 ORDER BY c.created_at DESC
 LIMIT 10;
diff --git a/content/docs/protocol/objectql/query-syntax.mdx b/content/docs/protocol/objectql/query-syntax.mdx
index c85c6ccf5..354106e92 100644
--- a/content/docs/protocol/objectql/query-syntax.mdx
+++ b/content/docs/protocol/objectql/query-syntax.mdx
@@ -407,7 +407,7 @@ SELECT
   o.amount, 
   a.company_name AS "account.company_name"
 FROM opportunity o
-LEFT JOIN account a ON o.account_id = a._id
+LEFT JOIN account a ON o.account_id = a.id
 ```
 
 ### Multiple Relationships
@@ -594,7 +594,7 @@ const query = {
     ['exists', {
       object: 'opportunity',
       filters: [
-        ['account_id', '=', '{{parent._id}}'],
+        ['account_id', '=', '{{parent.id}}'],
         ['stage', '=', 'Closed Won']
       ]
     }]
@@ -603,7 +603,7 @@ const query = {
 
 // SQL: WHERE EXISTS (
 //   SELECT 1 FROM opportunity 
-//   WHERE opportunity.account_id = account._id 
+//   WHERE opportunity.account_id = account.id 
 //   AND opportunity.stage = 'Closed Won'
 // )
 ```
@@ -617,7 +617,7 @@ const query = {
     ['not_exists', {
       object: 'opportunity',
       filters: [
-        ['account_id', '=', '{{parent._id}}']
+        ['account_id', '=', '{{parent.id}}']
       ]
     }]
   ]
@@ -778,17 +778,17 @@ const page2 = await ObjectQL.query({
 const result = await ObjectQL.query({
   object: 'customer',
   limit: 10,
-  sort: [{ field: '_id', order: 'asc' }]
+  sort: [{ field: 'id', order: 'asc' }]
 });
 
-// Next page (use last _id as cursor)
+// Next page (use last id as cursor)
 const nextResult = await ObjectQL.query({
   object: 'customer',
   filters: [
-    ['_id', '>', result[result.length - 1]._id]
+    ['id', '>', result[result.length - 1].id]
   ],
   limit: 10,
-  sort: [{ field: '_id', order: 'asc' }]
+  sort: [{ field: 'id', order: 'asc' }]
 });
 ```
 
@@ -808,7 +808,7 @@ const customer = await ObjectQL.findOne('customer', '123');
 // Equivalent to:
 await ObjectQL.query({
   object: 'customer',
-  filters: [['_id', '=', '123']],
+  filters: [['id', '=', '123']],
   limit: 1
 });
 ```
diff --git a/content/docs/protocol/objectql/schema.mdx b/content/docs/protocol/objectql/schema.mdx
index ddd32c97f..f43145926 100644
--- a/content/docs/protocol/objectql/schema.mdx
+++ b/content/docs/protocol/objectql/schema.mdx
@@ -75,7 +75,7 @@ label: Project
 ```
 
 This 2-line definition creates:
-- Database table `project` with system fields (`_id`, `created_at`, `updated_at`)
+- Database table `project` with system fields (`id`, `created_at`, `updated_at`)
 - REST API: `GET/POST/PUT/DELETE /api/project`
 - Admin UI: List view + Form
 - TypeScript types
@@ -303,7 +303,7 @@ Every object automatically includes system fields:
 
 ```yaml
 # Auto-generated (not defined in .object.yml)
-_id:
+id:
   type: id
   label: Record ID
   read_only: true
@@ -637,7 +637,7 @@ parent_id:
 Query polymorphic fields:
 ```typescript
 const activity = await ObjectQL.findOne('activity', id);
-// activity.parent_id = { _id: '123', _type: 'account' }
+// activity.parent_id = { id: '123', _type: 'account' }
 ```
 
 ### Computed Fields (Virtual)
diff --git a/content/docs/protocol/objectql/security.mdx b/content/docs/protocol/objectql/security.mdx
index b655127a3..99f206196 100644
--- a/content/docs/protocol/objectql/security.mdx
+++ b/content/docs/protocol/objectql/security.mdx
@@ -256,7 +256,7 @@ const user = await ObjectQL.findOne('user', '123');
 
 // Result (salary/ssn stripped):
 // {
-//   _id: '123',
+//   id: '123',
 //   name: 'John Doe',
 //   email: 'john@example.com'
 //   // salary: REMOVED
@@ -268,7 +268,7 @@ const user = await ObjectQL.findOne('user', '123');
 
 // Result (salary visible):
 // {
-//   _id: '123',
+//   id: '123',
 //   name: 'John Doe',
 //   email: 'john@example.com',
 //   salary: { amount: 120000, currency: 'USD' }
diff --git a/content/docs/protocol/objectql/types.mdx b/content/docs/protocol/objectql/types.mdx
index d56490579..2d2efae40 100644
--- a/content/docs/protocol/objectql/types.mdx
+++ b/content/docs/protocol/objectql/types.mdx
@@ -533,7 +533,7 @@ account_id:
   deleteBehavior: set_null  # or restrict, cascade
 ```
 
-**Storage:** Stores `_id` of referenced record
+**Storage:** Stores `id` of referenced record
 
 **Query behavior:**
 ```typescript
@@ -617,7 +617,7 @@ parent:
 **Storage:**
 ```json
 {
-  "_id": "123",
+  "id": "123",
   "_type": "account"
 }
 ```
@@ -628,12 +628,12 @@ const activity = await ObjectQL.findOne('activity', id, {
   expand: ['parent']  // Resolves based on _type
 });
 
-// activity.parent = { _id: '123', _type: 'account', company_name: 'Acme' }
+// activity.parent = { id: '123', _type: 'account', company_name: 'Acme' }
 ```
 
 **Database mapping:**
 - PostgreSQL: Two columns `parent_id` + `parent_type`
-- MongoDB: `{ _id: String, _type: String }`
+- MongoDB: `{ id: String, _type: String }`
 
 **Use cases:**
 - Activity feeds (related to Account OR Contact)
diff --git a/content/docs/protocol/objectui/actions.mdx b/content/docs/protocol/objectui/actions.mdx
index b524f85c9..0c2ea2f38 100644
--- a/content/docs/protocol/objectui/actions.mdx
+++ b/content/docs/protocol/objectui/actions.mdx
@@ -524,7 +524,7 @@ listView:
     - type: api
       label: Send Email
       icon: mail
-      endpoint: /api/customers/{_id}/send-email
+      endpoint: /api/customers/{id}/send-email
 ```
 
 ### Dropdown Menu Actions
@@ -541,7 +541,7 @@ actions:
         label: Clone Customer
       - type: api
         label: Export to PDF
-        endpoint: /api/customers/{_id}/export-pdf
+        endpoint: /api/customers/{id}/export-pdf
       - type: separator
       - type: workflow
         label: Merge Duplicate
diff --git a/content/docs/protocol/objectui/layout-dsl.mdx b/content/docs/protocol/objectui/layout-dsl.mdx
index 790c4f375..dc8176ea5 100644
--- a/content/docs/protocol/objectui/layout-dsl.mdx
+++ b/content/docs/protocol/objectui/layout-dsl.mdx
@@ -522,7 +522,7 @@ sections:
   - type: related_list
     label: Contacts
     object: contact
-    relationField: account_id  # contact.account_id → account._id
+    relationField: account_id  # contact.account_id → account.id
     columns:
       - name
       - email
diff --git a/content/docs/references/qa/testing.mdx b/content/docs/references/qa/testing.mdx
index d4a6cc7d1..9817bff68 100644
--- a/content/docs/references/qa/testing.mdx
+++ b/content/docs/references/qa/testing.mdx
@@ -126,7 +126,7 @@ A single step in a test scenario, consisting of an action and optional assertion
 | **description** | `string` | optional | Human-readable description of what this step tests |
 | **action** | `Object` | ✅ | The action to execute in this step |
 | **assertions** | `Object[]` | optional | Assertions to validate after the action completes |
-| **capture** | `Record<string, string>` | optional | Map result fields to context variables: `{ "newId": "body._id" }` |
+| **capture** | `Record<string, string>` | optional | Map result fields to context variables: `{ "newId": "body.id" }` |
 
 
 ---
diff --git a/content/prompts/platform/automation.prompt.md b/content/prompts/platform/automation.prompt.md
index 5ec818caf..895c38906 100644
--- a/content/prompts/platform/automation.prompt.md
+++ b/content/prompts/platform/automation.prompt.md
@@ -85,7 +85,7 @@ export const LeadQualifyFlow: FlowSchema = {
       label: 'Get Lead Details',
       config: {
         object: 'lead',
-        filter: [['_id', '=', '{leadId}']]
+        filter: [['id', '=', '{leadId}']]
       }
     },
     {
diff --git a/content/prompts/plugin/data-seed.prompt.md b/content/prompts/plugin/data-seed.prompt.md
index 8c2f6cab8..9eab262ed 100644
--- a/content/prompts/plugin/data-seed.prompt.md
+++ b/content/prompts/plugin/data-seed.prompt.md
@@ -46,7 +46,7 @@ export async function seedRoles() {
       await object.insert(role);
       console.log(`Created Role: ${role.name}`);
     } else {
-      await object.update(existing._id, role);
+      await object.update(existing.id, role);
       console.log(`Updated Role: ${role.name}`);
     }
   }
@@ -103,7 +103,7 @@ export const SplitNamesJob: JobSchema = {
     for (const c of contacts) {
        const [first, ...rest] = c.full_name.split(' ');
        await ctx.broker.call('contact.update', { 
-           id: c._id, 
+           id: c.id, 
            data: { first_name: first, last_name: rest.join(' ') } 
        });
     }
diff --git a/examples/app-crm/src/actions/handlers/case.handlers.ts b/examples/app-crm/src/actions/handlers/case.handlers.ts
index a0d45d37f..c1c672b74 100644
--- a/examples/app-crm/src/actions/handlers/case.handlers.ts
+++ b/examples/app-crm/src/actions/handlers/case.handlers.ts
@@ -24,7 +24,7 @@ interface ActionContext {
 /** Escalate a case to the escalation team */
 export async function escalateCase(ctx: ActionContext): Promise<void> {
   const { record, engine, user, params } = ctx;
-  await engine.update('case', record._id as string, {
+  await engine.update('case', record.id as string, {
     is_escalated: true,
     escalation_reason: params?.reason as string,
     escalated_by: user.id,
@@ -36,7 +36,7 @@ export async function escalateCase(ctx: ActionContext): Promise<void> {
 /** Close a case with a resolution */
 export async function closeCase(ctx: ActionContext): Promise<void> {
   const { record, engine, user, params } = ctx;
-  await engine.update('case', record._id as string, {
+  await engine.update('case', record.id as string, {
     is_closed: true,
     resolution: params?.resolution as string,
     closed_by: user.id,
diff --git a/examples/app-crm/src/actions/handlers/contact.handlers.ts b/examples/app-crm/src/actions/handlers/contact.handlers.ts
index 15918901e..3cacbdef0 100644
--- a/examples/app-crm/src/actions/handlers/contact.handlers.ts
+++ b/examples/app-crm/src/actions/handlers/contact.handlers.ts
@@ -17,7 +17,7 @@ interface ActionContext {
   user: { id: string; name: string };
   engine: {
     update(object: string, id: string, data: Record<string, unknown>): Promise<void>;
-    insert(object: string, data: Record<string, unknown>): Promise<{ _id: string }>;
+    insert(object: string, data: Record<string, unknown>): Promise<{ id: string }>;
     find(object: string, query: Record<string, unknown>): Promise<Array<Record<string, unknown>>>;
   };
   params?: Record<string, unknown>;
@@ -31,11 +31,11 @@ export async function markAsPrimaryContact(ctx: ActionContext): Promise<void> {
   // Clear existing primary contacts on the same account
   const siblings = await engine.find('contact', { account_id: accountId, is_primary: true });
   for (const sibling of siblings) {
-    await engine.update('contact', sibling._id as string, { is_primary: false });
+    await engine.update('contact', sibling.id as string, { is_primary: false });
   }
 
   // Set current contact as primary
-  await engine.update('contact', record._id as string, { is_primary: true });
+  await engine.update('contact', record.id as string, { is_primary: true });
 }
 
 /** Send an email to a contact (modal form submission handler) */
@@ -45,12 +45,12 @@ export async function sendEmail(ctx: ActionContext): Promise<{ activityId: strin
     type: 'email',
     subject: params?.subject ? String(params.subject) : `Email to ${record.email}`,
     body: params?.body ? String(params.body) : '',
-    contact_id: record._id as string,
+    contact_id: record.id as string,
     account_id: record.account_id as string,
     direction: 'outbound',
     status: 'sent',
     created_by: user.id,
     sent_at: new Date().toISOString(),
   });
-  return { activityId: activity._id };
+  return { activityId: activity.id };
 }
diff --git a/examples/app-crm/src/actions/handlers/global.handlers.ts b/examples/app-crm/src/actions/handlers/global.handlers.ts
index a1ec40564..cbda27750 100644
--- a/examples/app-crm/src/actions/handlers/global.handlers.ts
+++ b/examples/app-crm/src/actions/handlers/global.handlers.ts
@@ -16,7 +16,7 @@ interface ActionContext {
   record: Record<string, unknown>;
   user: { id: string; name: string };
   engine: {
-    insert(object: string, data: Record<string, unknown>): Promise<{ _id: string }>;
+    insert(object: string, data: Record<string, unknown>): Promise<{ id: string }>;
     find(object: string, query: Record<string, unknown>): Promise<Array<Record<string, unknown>>>;
   };
   params?: Record<string, unknown>;
@@ -43,11 +43,11 @@ export async function logCall(ctx: ActionContext): Promise<{ activityId: string
     subject: params?.subject ? String(params.subject) : 'Untitled Call',
     duration_minutes: params?.duration ? Number(params.duration) : 0,
     notes: params?.notes ? String(params.notes) : '',
-    related_to_id: record._id as string,
+    related_to_id: record.id as string,
     direction: 'outbound',
     status: 'completed',
     created_by: user.id,
     call_date: new Date().toISOString(),
   });
-  return { activityId: activity._id };
+  return { activityId: activity.id };
 }
diff --git a/examples/app-crm/src/actions/handlers/lead.handlers.ts b/examples/app-crm/src/actions/handlers/lead.handlers.ts
index 4d426d0e4..d5cdbc76c 100644
--- a/examples/app-crm/src/actions/handlers/lead.handlers.ts
+++ b/examples/app-crm/src/actions/handlers/lead.handlers.ts
@@ -20,7 +20,7 @@ interface ActionContext {
   user: { id: string; name: string };
   engine: {
     update(object: string, id: string, data: Record<string, unknown>): Promise<void>;
-    insert(object: string, data: Record<string, unknown>): Promise<{ _id: string }>;
+    insert(object: string, data: Record<string, unknown>): Promise<{ id: string }>;
     find(object: string, query: Record<string, unknown>): Promise<Array<Record<string, unknown>>>;
   };
   params?: Record<string, unknown>;
@@ -46,29 +46,29 @@ export async function convertLead(ctx: ActionContext): Promise<{
     last_name: record.last_name,
     email: record.email,
     phone: record.phone,
-    account_id: account._id,
+    account_id: account.id,
   });
 
   const opportunity = await engine.insert('opportunity', {
     name: `${record.company} - New Opportunity`,
-    account_id: account._id,
-    contact_id: contact._id,
+    account_id: account.id,
+    contact_id: contact.id,
     stage: 'prospecting',
     amount: record.estimated_value ?? 0,
   });
 
-  await engine.update('lead', record._id as string, {
+  await engine.update('lead', record.id as string, {
     is_converted: true,
     status: 'converted',
-    converted_account_id: account._id,
-    converted_contact_id: contact._id,
-    converted_opportunity_id: opportunity._id,
+    converted_account_id: account.id,
+    converted_contact_id: contact.id,
+    converted_opportunity_id: opportunity.id,
   });
 
   return {
-    accountId: account._id,
-    contactId: contact._id,
-    opportunityId: opportunity._id,
+    accountId: account.id,
+    contactId: contact.id,
+    opportunityId: opportunity.id,
   };
 }
 
diff --git a/examples/app-crm/src/actions/handlers/opportunity.handlers.ts b/examples/app-crm/src/actions/handlers/opportunity.handlers.ts
index 49d4abdc1..53edd0ead 100644
--- a/examples/app-crm/src/actions/handlers/opportunity.handlers.ts
+++ b/examples/app-crm/src/actions/handlers/opportunity.handlers.ts
@@ -16,16 +16,16 @@ interface ActionContext {
   user: { id: string; name: string };
   engine: {
     update(object: string, id: string, data: Record<string, unknown>): Promise<void>;
-    insert(object: string, data: Record<string, unknown>): Promise<{ _id: string }>;
+    insert(object: string, data: Record<string, unknown>): Promise<{ id: string }>;
     find(object: string, query: Record<string, unknown>): Promise<Array<Record<string, unknown>>>;
   };
   params?: Record<string, unknown>;
 }
 
 /** Clone an opportunity record */
-export async function cloneRecord(ctx: ActionContext): Promise<{ _id: string }> {
+export async function cloneRecord(ctx: ActionContext): Promise<{ id: string }> {
   const { record, engine } = ctx;
-  const { _id, created_at, updated_at, ...fields } = record as Record<string, unknown>;
+  const { id, created_at, updated_at, ...fields } = record as Record<string, unknown>;
   return engine.insert('opportunity', {
     ...fields,
     name: `Copy of ${fields.name ?? 'Untitled'}`,
diff --git a/examples/app-todo/src/actions/task.handlers.ts b/examples/app-todo/src/actions/task.handlers.ts
index 771cee766..a7b3dfc64 100644
--- a/examples/app-todo/src/actions/task.handlers.ts
+++ b/examples/app-todo/src/actions/task.handlers.ts
@@ -23,7 +23,7 @@ interface ActionContext {
   /** Data engine for CRUD operations */
   engine: {
     update(object: string, id: string, data: Record<string, unknown>): Promise<void>;
-    insert(object: string, data: Record<string, unknown>): Promise<{ _id: string }>;
+    insert(object: string, data: Record<string, unknown>): Promise<{ id: string }>;
     find(object: string, query: Record<string, unknown>): Promise<Array<Record<string, unknown>>>;
     delete(object: string, ids: string[]): Promise<void>;
   };
@@ -34,7 +34,7 @@ interface ActionContext {
 /** Mark a single task as complete */
 export async function completeTask(ctx: ActionContext): Promise<void> {
   const { record, engine, user } = ctx;
-  await engine.update('task', record._id as string, {
+  await engine.update('task', record.id as string, {
     status: 'completed',
     completed_at: new Date().toISOString(),
     completed_by: user.id,
@@ -44,16 +44,16 @@ export async function completeTask(ctx: ActionContext): Promise<void> {
 /** Mark a task as in-progress */
 export async function startTask(ctx: ActionContext): Promise<void> {
   const { record, engine } = ctx;
-  await engine.update('task', record._id as string, {
+  await engine.update('task', record.id as string, {
     status: 'in_progress',
     started_at: new Date().toISOString(),
   });
 }
 
 /** Clone a task (duplicate with reset status) */
-export async function cloneTask(ctx: ActionContext): Promise<{ _id: string }> {
+export async function cloneTask(ctx: ActionContext): Promise<{ id: string }> {
   const { record, engine } = ctx;
-  const { _id, created_at, updated_at, completed_at, completed_by, ...fields } = record as Record<string, unknown>;
+  const { id, created_at, updated_at, completed_at, completed_by, ...fields } = record as Record<string, unknown>;
   return engine.insert('task', {
     ...fields,
     status: 'not_started',
@@ -79,7 +79,7 @@ export async function massCompleteTasks(ctx: ActionContext): Promise<void> {
 export async function deleteCompletedTasks(ctx: ActionContext): Promise<void> {
   const { engine } = ctx;
   const completed = await engine.find('task', { status: 'completed' });
-  const ids = completed.map((r) => r._id as string);
+  const ids = completed.map((r) => r.id as string);
   if (ids.length > 0) {
     await engine.delete('task', ids);
   }
@@ -88,7 +88,7 @@ export async function deleteCompletedTasks(ctx: ActionContext): Promise<void> {
 /** Defer a task by updating its due date (modal form submission handler) */
 export async function deferTask(ctx: ActionContext): Promise<void> {
   const { record, engine, params } = ctx;
-  await engine.update('task', record._id as string, {
+  await engine.update('task', record.id as string, {
     due_date: params?.new_due_date ? String(params.new_due_date) : null,
     defer_reason: params?.reason ? String(params.reason) : null,
     status: 'waiting',
@@ -98,7 +98,7 @@ export async function deferTask(ctx: ActionContext): Promise<void> {
 /** Set a reminder on a task (modal form submission handler) */
 export async function setReminder(ctx: ActionContext): Promise<void> {
   const { record, engine, params } = ctx;
-  await engine.update('task', record._id as string, {
+  await engine.update('task', record.id as string, {
     reminder_date: params?.reminder_date ? String(params.reminder_date) : null,
     has_reminder: true,
   });
diff --git a/packages/client/src/client.hono.test.ts b/packages/client/src/client.hono.test.ts
index 1f8bcbf46..c664fd9fe 100644
--- a/packages/client/src/client.hono.test.ts
+++ b/packages/client/src/client.hono.test.ts
@@ -37,7 +37,7 @@ describe('ObjectStackClient (with Hono Server)', () => {
                     if (method === 'create') {
                         const res = await ql.insert(params.object, params.data);
                         const record = { ...params.data, ...res };
-                        return { object: params.object, id: record.id || record._id, record };
+                        return { object: params.object, id: record.id, record };
                     }
                     // Params from HttpDispatcher: { object, id, ...query }
                     if (method === 'get') {
diff --git a/packages/client/src/client.msw.test.ts b/packages/client/src/client.msw.test.ts
index a2a2d7559..2a4d5cbaf 100644
--- a/packages/client/src/client.msw.test.ts
+++ b/packages/client/src/client.msw.test.ts
@@ -43,7 +43,7 @@ describe('ObjectStackClient (with MSW Plugin)', () => {
                     if (method === 'create') {
                          const res = await ql.insert(params.object, params.data);
                          const record = { ...params.data, ...res };
-                         return { object: params.object, id: record.id || record._id, record };
+                         return { object: params.object, id: record.id, record };
                     }
                     if (method === 'get') {
                         if (protocol) {
diff --git a/packages/core/src/qa/http-adapter.ts b/packages/core/src/qa/http-adapter.ts
index b7f0fd469..f2b76b1aa 100644
--- a/packages/core/src/qa/http-adapter.ts
+++ b/packages/core/src/qa/http-adapter.ts
@@ -49,8 +49,8 @@ export class HttpTestAdapter implements TestExecutionAdapter {
   }
 
   private async updateRecord(objectName: string, data: Record<string, unknown>, headers: Record<string, string>) {
-    const id = data._id || data.id;
-    if (!id) throw new Error('Update record requires _id or id in payload');
+    const id = data.id;
+    if (!id) throw new Error('Update record requires id in payload');
     const response = await fetch(`${this.baseUrl}/api/data/${objectName}/${id}`, {
       method: 'PUT',
       headers,
@@ -60,8 +60,8 @@ export class HttpTestAdapter implements TestExecutionAdapter {
   }
 
   private async deleteRecord(objectName: string, data: Record<string, unknown>, headers: Record<string, string>) {
-    const id = data._id || data.id;
-    if (!id) throw new Error('Delete record requires _id or id in payload');
+    const id = data.id;
+    if (!id) throw new Error('Delete record requires id in payload');
     const response = await fetch(`${this.baseUrl}/api/data/${objectName}/${id}`, {
       method: 'DELETE',
       headers
@@ -70,8 +70,8 @@ export class HttpTestAdapter implements TestExecutionAdapter {
   }
 
   private async readRecord(objectName: string, data: Record<string, unknown>, headers: Record<string, string>) {
-    const id = data._id || data.id;
-    if (!id) throw new Error('Read record requires _id or id in payload');
+    const id = data.id;
+    if (!id) throw new Error('Read record requires id in payload');
     const response = await fetch(`${this.baseUrl}/api/data/${objectName}/${id}`, {
       method: 'GET',
       headers
diff --git a/packages/objectql/src/engine.test.ts b/packages/objectql/src/engine.test.ts
index 488b52067..01a2579e0 100644
--- a/packages/objectql/src/engine.test.ts
+++ b/packages/objectql/src/engine.test.ts
@@ -239,20 +239,20 @@ describe('ObjectQL Engine', () => {
             // Primary find returns tasks with assignee IDs
             vi.mocked(mockDriver.find)
                 .mockResolvedValueOnce([
-                    { _id: 't1', title: 'Task 1', assignee: 'u1' },
-                    { _id: 't2', title: 'Task 2', assignee: 'u2' },
+                    { id: 't1', title: 'Task 1', assignee: 'u1' },
+                    { id: 't2', title: 'Task 2', assignee: 'u2' },
                 ])
                 // Second call (expand): returns user records
                 .mockResolvedValueOnce([
-                    { _id: 'u1', name: 'Alice' },
-                    { _id: 'u2', name: 'Bob' },
+                    { id: 'u1', name: 'Alice' },
+                    { id: 'u2', name: 'Bob' },
                 ]);
 
             const result = await engine.find('task', { populate: ['assignee'] });
 
             expect(result).toHaveLength(2);
-            expect(result[0].assignee).toEqual({ _id: 'u1', name: 'Alice' });
-            expect(result[1].assignee).toEqual({ _id: 'u2', name: 'Bob' });
+            expect(result[0].assignee).toEqual({ id: 'u1', name: 'Alice' });
+            expect(result[1].assignee).toEqual({ id: 'u2', name: 'Bob' });
 
             // Verify the expand query used $in
             expect(mockDriver.find).toHaveBeenCalledTimes(2);
@@ -260,7 +260,7 @@ describe('ObjectQL Engine', () => {
                 'user',
                 expect.objectContaining({
                     object: 'user',
-                    where: { _id: { $in: ['u1', 'u2'] } },
+                    where: { id: { $in: ['u1', 'u2'] } },
                 }),
             );
         });
@@ -282,14 +282,14 @@ describe('ObjectQL Engine', () => {
 
             vi.mocked(mockDriver.find)
                 .mockResolvedValueOnce([
-                    { _id: 'oi1', order: 'o1' },
+                    { id: 'oi1', order: 'o1' },
                 ])
                 .mockResolvedValueOnce([
-                    { _id: 'o1', total: 100 },
+                    { id: 'o1', total: 100 },
                 ]);
 
             const result = await engine.find('order_item', { populate: ['order'] });
-            expect(result[0].order).toEqual({ _id: 'o1', total: 100 });
+            expect(result[0].order).toEqual({ id: 'o1', total: 100 });
         });
 
         it('should skip expand for fields without reference definition', async () => {
@@ -301,7 +301,7 @@ describe('ObjectQL Engine', () => {
             } as any);
 
             vi.mocked(mockDriver.find).mockResolvedValueOnce([
-                { _id: 't1', title: 'Task 1' },
+                { id: 't1', title: 'Task 1' },
             ]);
 
             const result = await engine.find('task', { populate: ['title'] });
@@ -313,7 +313,7 @@ describe('ObjectQL Engine', () => {
             vi.mocked(SchemaRegistry.getObject).mockReturnValue(undefined);
 
             vi.mocked(mockDriver.find).mockResolvedValueOnce([
-                { _id: 't1', assignee: 'u1' },
+                { id: 't1', assignee: 'u1' },
             ]);
 
             const result = await engine.find('task', { populate: ['assignee'] });
@@ -338,16 +338,16 @@ describe('ObjectQL Engine', () => {
 
             vi.mocked(mockDriver.find)
                 .mockResolvedValueOnce([
-                    { _id: 't1', assignee: null },
-                    { _id: 't2', assignee: 'u1' },
+                    { id: 't1', assignee: null },
+                    { id: 't2', assignee: 'u1' },
                 ])
                 .mockResolvedValueOnce([
-                    { _id: 'u1', name: 'Alice' },
+                    { id: 'u1', name: 'Alice' },
                 ]);
 
             const result = await engine.find('task', { populate: ['assignee'] });
             expect(result[0].assignee).toBeNull();
-            expect(result[1].assignee).toEqual({ _id: 'u1', name: 'Alice' });
+            expect(result[1].assignee).toEqual({ id: 'u1', name: 'Alice' });
         });
 
         it('should de-duplicate foreign key IDs in batch query', async () => {
@@ -367,13 +367,13 @@ describe('ObjectQL Engine', () => {
 
             vi.mocked(mockDriver.find)
                 .mockResolvedValueOnce([
-                    { _id: 't1', assignee: 'u1' },
-                    { _id: 't2', assignee: 'u1' }, // Same user
-                    { _id: 't3', assignee: 'u2' },
+                    { id: 't1', assignee: 'u1' },
+                    { id: 't2', assignee: 'u1' }, // Same user
+                    { id: 't3', assignee: 'u2' },
                 ])
                 .mockResolvedValueOnce([
-                    { _id: 'u1', name: 'Alice' },
-                    { _id: 'u2', name: 'Bob' },
+                    { id: 'u1', name: 'Alice' },
+                    { id: 'u2', name: 'Bob' },
                 ]);
 
             const result = await engine.find('task', { populate: ['assignee'] });
@@ -382,11 +382,11 @@ describe('ObjectQL Engine', () => {
             expect(mockDriver.find).toHaveBeenLastCalledWith(
                 'user',
                 expect.objectContaining({
-                    where: { _id: { $in: ['u1', 'u2'] } },
+                    where: { id: { $in: ['u1', 'u2'] } },
                 }),
             );
-            expect(result[0].assignee).toEqual({ _id: 'u1', name: 'Alice' });
-            expect(result[1].assignee).toEqual({ _id: 'u1', name: 'Alice' });
+            expect(result[0].assignee).toEqual({ id: 'u1', name: 'Alice' });
+            expect(result[1].assignee).toEqual({ id: 'u1', name: 'Alice' });
         });
 
         it('should keep raw ID when referenced record not found', async () => {
@@ -406,7 +406,7 @@ describe('ObjectQL Engine', () => {
 
             vi.mocked(mockDriver.find)
                 .mockResolvedValueOnce([
-                    { _id: 't1', assignee: 'u_deleted' },
+                    { id: 't1', assignee: 'u_deleted' },
                 ])
                 .mockResolvedValueOnce([]); // No records found
 
@@ -436,15 +436,15 @@ describe('ObjectQL Engine', () => {
 
             vi.mocked(mockDriver.find)
                 .mockResolvedValueOnce([
-                    { _id: 't1', assignee: 'u1', project: 'p1' },
+                    { id: 't1', assignee: 'u1', project: 'p1' },
                 ])
-                .mockResolvedValueOnce([{ _id: 'u1', name: 'Alice' }])
-                .mockResolvedValueOnce([{ _id: 'p1', name: 'Project X' }]);
+                .mockResolvedValueOnce([{ id: 'u1', name: 'Alice' }])
+                .mockResolvedValueOnce([{ id: 'p1', name: 'Project X' }]);
 
             const result = await engine.find('task', { populate: ['assignee', 'project'] });
 
-            expect(result[0].assignee).toEqual({ _id: 'u1', name: 'Alice' });
-            expect(result[0].project).toEqual({ _id: 'p1', name: 'Project X' });
+            expect(result[0].assignee).toEqual({ id: 'u1', name: 'Alice' });
+            expect(result[0].project).toEqual({ id: 'p1', name: 'Project X' });
             expect(mockDriver.find).toHaveBeenCalledTimes(3);
         });
 
@@ -464,15 +464,15 @@ describe('ObjectQL Engine', () => {
             });
 
             vi.mocked(mockDriver.findOne as any).mockResolvedValueOnce(
-                { _id: 't1', title: 'Task 1', assignee: 'u1' },
+                { id: 't1', title: 'Task 1', assignee: 'u1' },
             );
             vi.mocked(mockDriver.find).mockResolvedValueOnce([
-                { _id: 'u1', name: 'Alice' },
+                { id: 'u1', name: 'Alice' },
             ]);
 
             const result = await engine.findOne('task', { populate: ['assignee'] });
 
-            expect(result.assignee).toEqual({ _id: 'u1', name: 'Alice' });
+            expect(result.assignee).toEqual({ id: 'u1', name: 'Alice' });
         });
 
         it('should handle already-expanded objects (skip re-expansion)', async () => {
@@ -492,14 +492,14 @@ describe('ObjectQL Engine', () => {
 
             // Driver returns an already-expanded object
             vi.mocked(mockDriver.find).mockResolvedValueOnce([
-                { _id: 't1', assignee: { _id: 'u1', name: 'Alice' } },
+                { id: 't1', assignee: { id: 'u1', name: 'Alice' } },
             ]);
 
             const result = await engine.find('task', { populate: ['assignee'] });
 
             // No expand query should have been made — the value was already an object
             expect(mockDriver.find).toHaveBeenCalledTimes(1);
-            expect(result[0].assignee).toEqual({ _id: 'u1', name: 'Alice' });
+            expect(result[0].assignee).toEqual({ id: 'u1', name: 'Alice' });
         });
 
         it('should gracefully handle expand errors and keep raw IDs', async () => {
@@ -519,7 +519,7 @@ describe('ObjectQL Engine', () => {
 
             vi.mocked(mockDriver.find)
                 .mockResolvedValueOnce([
-                    { _id: 't1', assignee: 'u1' },
+                    { id: 't1', assignee: 'u1' },
                 ])
                 .mockRejectedValueOnce(new Error('Driver connection failed'));
 
@@ -544,17 +544,17 @@ describe('ObjectQL Engine', () => {
 
             vi.mocked(mockDriver.find)
                 .mockResolvedValueOnce([
-                    { _id: 't1', watchers: ['u1', 'u2'] },
+                    { id: 't1', watchers: ['u1', 'u2'] },
                 ])
                 .mockResolvedValueOnce([
-                    { _id: 'u1', name: 'Alice' },
-                    { _id: 'u2', name: 'Bob' },
+                    { id: 'u1', name: 'Alice' },
+                    { id: 'u2', name: 'Bob' },
                 ]);
 
             const result = await engine.find('task', { populate: ['watchers'] });
             expect(result[0].watchers).toEqual([
-                { _id: 'u1', name: 'Alice' },
-                { _id: 'u2', name: 'Bob' },
+                { id: 'u1', name: 'Alice' },
+                { id: 'u2', name: 'Bob' },
             ]);
         });
 
@@ -570,14 +570,14 @@ describe('ObjectQL Engine', () => {
             });
 
             vi.mocked(mockDriver.find)
-                .mockResolvedValueOnce([{ _id: 't1', project: 'p1' }])  // find task
-                .mockResolvedValueOnce([{ _id: 'p1', org: 'o1' }]);     // expand project (depth 0)
+                .mockResolvedValueOnce([{ id: 't1', project: 'p1' }])  // find task
+                .mockResolvedValueOnce([{ id: 'p1', org: 'o1' }]);     // expand project (depth 0)
                 // org should NOT be expanded further — flat populate doesn't create nested expand
 
             const result = await engine.find('task', { populate: ['project'] });
 
             // Project expanded, but org inside project remains as raw ID
-            expect(result[0].project).toEqual({ _id: 'p1', org: 'o1' });
+            expect(result[0].project).toEqual({ id: 'p1', org: 'o1' });
             expect(mockDriver.find).toHaveBeenCalledTimes(2); // Only primary + 1 expand query
         });
 
@@ -588,11 +588,11 @@ describe('ObjectQL Engine', () => {
             } as any);
 
             vi.mocked(mockDriver.find).mockResolvedValueOnce([
-                { _id: 't1', title: 'Task 1' },
+                { id: 't1', title: 'Task 1' },
             ]);
 
             const result = await engine.find('task', {});
-            expect(result).toEqual([{ _id: 't1', title: 'Task 1' }]);
+            expect(result).toEqual([{ id: 't1', title: 'Task 1' }]);
             expect(mockDriver.find).toHaveBeenCalledTimes(1);
         });
     });
diff --git a/packages/objectql/src/engine.ts b/packages/objectql/src/engine.ts
index a2ef591ab..72063fe87 100644
--- a/packages/objectql/src/engine.ts
+++ b/packages/objectql/src/engine.ts
@@ -681,7 +681,7 @@ export class ObjectQL implements IDataEngine {
       try {
         const relatedQuery: QueryAST = {
           object: referenceObject,
-          where: { _id: { $in: uniqueIds } },
+          where: { id: { $in: uniqueIds } },
           ...(nestedAST.fields ? { fields: nestedAST.fields } : {}),
           ...(nestedAST.orderBy ? { orderBy: nestedAST.orderBy } : {}),
         };
@@ -692,7 +692,7 @@ export class ObjectQL implements IDataEngine {
         // Build a lookup map: id → record
         const recordMap = new Map<string, any>();
         for (const rec of relatedRecords) {
-          const id = rec._id ?? rec.id;
+          const id = rec.id;
           if (id != null) recordMap.set(String(id), rec);
         }
 
@@ -707,7 +707,7 @@ export class ObjectQL implements IDataEngine {
           // Rebuild map with expanded records
           recordMap.clear();
           for (const rec of expandedRelated) {
-            const id = rec._id ?? rec.id;
+            const id = rec.id;
             if (id != null) recordMap.set(String(id), rec);
           }
         }
@@ -921,10 +921,9 @@ export class ObjectQL implements IDataEngine {
      const driver = this.getDriver(object);
      
      // 1. Extract ID from data or filter if it's a single update by ID
-     let id = data.id || data._id;
+     let id = data.id;
      if (!id && options?.filter) {
          if (typeof options.filter === 'string') id = options.filter;
-         else if (options.filter._id) id = options.filter._id;
          else if (options.filter.id) id = options.filter.id;
      }
 
@@ -980,7 +979,6 @@ export class ObjectQL implements IDataEngine {
     let id: any = undefined;
     if (options?.filter) {
          if (typeof options.filter === 'string') id = options.filter;
-         else if (options.filter._id) id = options.filter._id;
          else if (options.filter.id) id = options.filter.id;
     }
 
@@ -1043,7 +1041,7 @@ export class ObjectQL implements IDataEngine {
            return driver.count(object, ast);
        }
        // Fallback to find().length
-       const res = await this.find(object, { filter: query?.filter, select: ['_id'] });
+       const res = await this.find(object, { filter: query?.filter, select: ['id'] });
        return res.length;
      });
 
@@ -1335,8 +1333,8 @@ export class ObjectRepository {
 
   /** Update a single record by ID */
   async updateById(id: string | number, data: any): Promise<any> {
-    return this.engine.update(this.objectName, { ...data, _id: id }, {
-      filter: { _id: id },
+    return this.engine.update(this.objectName, { ...data, id: id }, {
+      filter: { id: id },
       context: this.context,
     });
   }
@@ -1351,7 +1349,7 @@ export class ObjectRepository {
   /** Delete a single record by ID */
   async deleteById(id: string | number): Promise<any> {
     return this.engine.delete(this.objectName, {
-      filter: { _id: id },
+      filter: { id: id },
       context: this.context,
     });
   }
diff --git a/packages/objectql/src/plugin.ts b/packages/objectql/src/plugin.ts
index 040c55cb8..c83cdc1d8 100644
--- a/packages/objectql/src/plugin.ts
+++ b/packages/objectql/src/plugin.ts
@@ -129,35 +129,35 @@ export class ObjectQLPlugin implements Plugin {
   }
 
   /**
-   * Register built-in audit hooks for auto-stamping createdBy/modifiedBy
+   * Register built-in audit hooks for auto-stamping created_by/updated_by
    * and fetching previousData for update/delete operations.
    */
   private registerAuditHooks(ctx: PluginContext) {
     if (!this.ql) return;
 
-    // Auto-stamp createdBy/modifiedBy on insert
+    // Auto-stamp created_by/updated_by on insert
     this.ql.registerHook('beforeInsert', async (hookCtx) => {
       if (hookCtx.session?.userId && hookCtx.input?.data) {
         const data = hookCtx.input.data as Record<string, any>;
         if (typeof data === 'object' && data !== null) {
           data.created_by = data.created_by ?? hookCtx.session.userId;
-          data.modified_by = hookCtx.session.userId;
+          data.updated_by = hookCtx.session.userId;
           data.created_at = data.created_at ?? new Date().toISOString();
-          data.modified_at = new Date().toISOString();
+          data.updated_at = new Date().toISOString();
           if (hookCtx.session.tenantId) {
-            data.space_id = data.space_id ?? hookCtx.session.tenantId;
+            data.tenant_id = data.tenant_id ?? hookCtx.session.tenantId;
           }
         }
       }
     }, { object: '*', priority: 10 });
 
-    // Auto-stamp modifiedBy on update
+    // Auto-stamp updated_by on update
     this.ql.registerHook('beforeUpdate', async (hookCtx) => {
       if (hookCtx.session?.userId && hookCtx.input?.data) {
         const data = hookCtx.input.data as Record<string, any>;
         if (typeof data === 'object' && data !== null) {
-          data.modified_by = hookCtx.session.userId;
-          data.modified_at = new Date().toISOString();
+          data.updated_by = hookCtx.session.userId;
+          data.updated_at = new Date().toISOString();
         }
       }
     }, { object: '*', priority: 10 });
@@ -167,7 +167,7 @@ export class ObjectQLPlugin implements Plugin {
       if (hookCtx.input?.id && !hookCtx.previous) {
         try {
           const existing = await this.ql!.findOne(hookCtx.object, {
-            filter: { _id: hookCtx.input.id }
+            filter: { id: hookCtx.input.id }
           });
           if (existing) {
             hookCtx.previous = existing;
@@ -183,7 +183,7 @@ export class ObjectQLPlugin implements Plugin {
       if (hookCtx.input?.id && !hookCtx.previous) {
         try {
           const existing = await this.ql!.findOne(hookCtx.object, {
-            filter: { _id: hookCtx.input.id }
+            filter: { id: hookCtx.input.id }
           });
           if (existing) {
             hookCtx.previous = existing;
@@ -194,11 +194,11 @@ export class ObjectQLPlugin implements Plugin {
       }
     }, { object: '*', priority: 5 });
 
-    ctx.logger.debug('Audit hooks registered (createdBy/modifiedBy, previousData)');
+    ctx.logger.debug('Audit hooks registered (created_by/updated_by, previousData)');
   }
 
   /**
-   * Register tenant isolation middleware that auto-injects space_id filter
+   * Register tenant isolation middleware that auto-injects tenant_id filter
    * for multi-tenant operations.
    */
   private registerTenantMiddleware(ctx: PluginContext) {
@@ -210,10 +210,10 @@ export class ObjectQLPlugin implements Plugin {
         return next();
       }
 
-      // Read operations: inject space_id filter into AST
+      // Read operations: inject tenant_id filter into AST
       if (['find', 'findOne', 'count', 'aggregate'].includes(opCtx.operation)) {
         if (opCtx.ast) {
-          const tenantFilter = { space_id: opCtx.context.tenantId };
+          const tenantFilter = { tenant_id: opCtx.context.tenantId };
           if (opCtx.ast.where) {
             opCtx.ast.where = { $and: [opCtx.ast.where, tenantFilter] };
           } else {
diff --git a/packages/objectql/src/protocol-data.test.ts b/packages/objectql/src/protocol-data.test.ts
index 5f7382ccd..6950bba01 100644
--- a/packages/objectql/src/protocol-data.test.ts
+++ b/packages/objectql/src/protocol-data.test.ts
@@ -129,14 +129,14 @@ describe('ObjectStackProtocolImplementation - Data Operations', () => {
         });
 
         it('should return records and standard response shape', async () => {
-            mockEngine.find.mockResolvedValue([{ _id: 't1', name: 'Task 1' }]);
+            mockEngine.find.mockResolvedValue([{ id: 't1', name: 'Task 1' }]);
 
             const result = await protocol.findData({ object: 'task', query: {} });
 
             expect(result).toEqual(
                 expect.objectContaining({
                     object: 'task',
-                    records: [{ _id: 't1', name: 'Task 1' }],
+                    records: [{ id: 't1', name: 'Task 1' }],
                     total: 1,
                 }),
             );
@@ -149,21 +149,21 @@ describe('ObjectStackProtocolImplementation - Data Operations', () => {
 
     describe('getData', () => {
         it('should convert expand string to populate array', async () => {
-            mockEngine.findOne.mockResolvedValue({ _id: 'oi_1', name: 'Item 1' });
+            mockEngine.findOne.mockResolvedValue({ id: 'oi_1', name: 'Item 1' });
 
             await protocol.getData({ object: 'order_item', id: 'oi_1', expand: 'order,product' });
 
             expect(mockEngine.findOne).toHaveBeenCalledWith(
                 'order_item',
                 expect.objectContaining({
-                    filter: { _id: 'oi_1' },
+                    filter: { id: 'oi_1' },
                     populate: ['order', 'product'],
                 }),
             );
         });
 
         it('should convert expand array to populate array', async () => {
-            mockEngine.findOne.mockResolvedValue({ _id: 't1' });
+            mockEngine.findOne.mockResolvedValue({ id: 't1' });
 
             await protocol.getData({ object: 'task', id: 't1', expand: ['assignee', 'project'] });
 
@@ -176,7 +176,7 @@ describe('ObjectStackProtocolImplementation - Data Operations', () => {
         });
 
         it('should convert select string to array', async () => {
-            mockEngine.findOne.mockResolvedValue({ _id: 't1', name: 'Test' });
+            mockEngine.findOne.mockResolvedValue({ id: 't1', name: 'Test' });
 
             await protocol.getData({ object: 'task', id: 't1', select: 'name,status' });
 
@@ -189,7 +189,7 @@ describe('ObjectStackProtocolImplementation - Data Operations', () => {
         });
 
         it('should pass both expand and select together', async () => {
-            mockEngine.findOne.mockResolvedValue({ _id: 'oi_1' });
+            mockEngine.findOne.mockResolvedValue({ id: 'oi_1' });
 
             await protocol.getData({
                 object: 'order_item',
@@ -201,7 +201,7 @@ describe('ObjectStackProtocolImplementation - Data Operations', () => {
             expect(mockEngine.findOne).toHaveBeenCalledWith(
                 'order_item',
                 expect.objectContaining({
-                    filter: { _id: 'oi_1' },
+                    filter: { id: 'oi_1' },
                     populate: ['order'],
                     select: ['name', 'total'],
                 }),
@@ -209,25 +209,25 @@ describe('ObjectStackProtocolImplementation - Data Operations', () => {
         });
 
         it('should work without expand or select', async () => {
-            mockEngine.findOne.mockResolvedValue({ _id: 't1' });
+            mockEngine.findOne.mockResolvedValue({ id: 't1' });
 
             await protocol.getData({ object: 'task', id: 't1' });
 
             expect(mockEngine.findOne).toHaveBeenCalledWith(
                 'task',
-                { filter: { _id: 't1' } },
+                { filter: { id: 't1' } },
             );
         });
 
         it('should return standard GetDataResponse shape', async () => {
-            mockEngine.findOne.mockResolvedValue({ _id: 'oi_1', name: 'Item 1' });
+            mockEngine.findOne.mockResolvedValue({ id: 'oi_1', name: 'Item 1' });
 
             const result = await protocol.getData({ object: 'order_item', id: 'oi_1' });
 
             expect(result).toEqual({
                 object: 'order_item',
                 id: 'oi_1',
-                record: { _id: 'oi_1', name: 'Item 1' },
+                record: { id: 'oi_1', name: 'Item 1' },
             });
         });
 
diff --git a/packages/objectql/src/protocol.ts b/packages/objectql/src/protocol.ts
index 7537ed929..26a4b3152 100644
--- a/packages/objectql/src/protocol.ts
+++ b/packages/objectql/src/protocol.ts
@@ -246,7 +246,7 @@ export class ObjectStackProtocolImplementation implements ObjectStackProtocol {
              // Form View Generation
              // Simple single-section layout for now
              const formFields = fieldKeys
-                .filter(k => k !== 'id' && k !== 'created_at' && k !== 'modified_at' && !fields[k].hidden)
+                .filter(k => k !== 'id' && k !== 'created_at' && k !== 'updated_at' && !fields[k].hidden)
                 .map(f => ({
                     field: f,
                     label: fields[f]?.label,
@@ -361,7 +361,7 @@ export class ObjectStackProtocolImplementation implements ObjectStackProtocol {
 
     async getData(request: { object: string, id: string, expand?: string | string[], select?: string | string[] }) {
         const queryOptions: any = {
-            filter: { _id: request.id }
+            filter: { id: request.id }
         };
 
         // Support select for single-record retrieval
@@ -393,14 +393,14 @@ export class ObjectStackProtocolImplementation implements ObjectStackProtocol {
         const result = await this.engine.insert(request.object, request.data);
         return {
             object: request.object,
-            id: result._id || result.id,
+            id: result.id,
             record: result
         };
     }
 
     async updateData(request: { object: string, id: string, data: any }) {
         // Adapt: update(obj, id, data) -> update(obj, data, options)
-        const result = await this.engine.update(request.object, request.data, { filter: { _id: request.id } });
+        const result = await this.engine.update(request.object, request.data, { filter: { id: request.id } });
         return {
             object: request.object,
             id: request.id,
@@ -410,7 +410,7 @@ export class ObjectStackProtocolImplementation implements ObjectStackProtocol {
 
     async deleteData(request: { object: string, id: string }) {
         // Adapt: delete(obj, id) -> delete(obj, options)
-        await this.engine.delete(request.object, { filter: { _id: request.id } });
+        await this.engine.delete(request.object, { filter: { id: request.id } });
         return {
             object: request.object,
             id: request.id,
@@ -478,13 +478,13 @@ export class ObjectStackProtocolImplementation implements ObjectStackProtocol {
                 switch (operation) {
                     case 'create': {
                         const created = await this.engine.insert(object, record.data || record);
-                        results.push({ id: created._id || created.id, success: true, record: created });
+                        results.push({ id: created.id, success: true, record: created });
                         succeeded++;
                         break;
                     }
                     case 'update': {
                         if (!record.id) throw new Error('Record id is required for update');
-                        const updated = await this.engine.update(object, record.data || {}, { filter: { _id: record.id } });
+                        const updated = await this.engine.update(object, record.data || {}, { filter: { id: record.id } });
                         results.push({ id: record.id, success: true, record: updated });
                         succeeded++;
                         break;
@@ -493,28 +493,28 @@ export class ObjectStackProtocolImplementation implements ObjectStackProtocol {
                         // Try update first, then create if not found
                         if (record.id) {
                             try {
-                                const existing = await this.engine.findOne(object, { filter: { _id: record.id } });
+                                const existing = await this.engine.findOne(object, { filter: { id: record.id } });
                                 if (existing) {
-                                    const updated = await this.engine.update(object, record.data || {}, { filter: { _id: record.id } });
+                                    const updated = await this.engine.update(object, record.data || {}, { filter: { id: record.id } });
                                     results.push({ id: record.id, success: true, record: updated });
                                 } else {
-                                    const created = await this.engine.insert(object, { _id: record.id, ...(record.data || {}) });
-                                    results.push({ id: created._id || created.id, success: true, record: created });
+                                    const created = await this.engine.insert(object, { id: record.id, ...(record.data || {}) });
+                                    results.push({ id: created.id, success: true, record: created });
                                 }
                             } catch {
-                                const created = await this.engine.insert(object, { _id: record.id, ...(record.data || {}) });
-                                results.push({ id: created._id || created.id, success: true, record: created });
+                                const created = await this.engine.insert(object, { id: record.id, ...(record.data || {}) });
+                                results.push({ id: created.id, success: true, record: created });
                             }
                         } else {
                             const created = await this.engine.insert(object, record.data || record);
-                            results.push({ id: created._id || created.id, success: true, record: created });
+                            results.push({ id: created.id, success: true, record: created });
                         }
                         succeeded++;
                         break;
                     }
                     case 'delete': {
                         if (!record.id) throw new Error('Record id is required for delete');
-                        await this.engine.delete(object, { filter: { _id: record.id } });
+                        await this.engine.delete(object, { filter: { id: record.id } });
                         results.push({ id: record.id, success: true });
                         succeeded++;
                         break;
@@ -563,7 +563,7 @@ export class ObjectStackProtocolImplementation implements ObjectStackProtocol {
 
         for (const record of records) {
             try {
-                const updated = await this.engine.update(object, record.data, { filter: { _id: record.id } });
+                const updated = await this.engine.update(object, record.data, { filter: { id: record.id } });
                 results.push({ id: record.id, success: true, record: updated });
                 succeeded++;
             } catch (err: any) {
@@ -765,7 +765,7 @@ export class ObjectStackProtocolImplementation implements ObjectStackProtocol {
     async deleteManyData(request: DeleteManyDataRequest): Promise<any> {
         // This expects deleting by IDs.
         return this.engine.delete(request.object, {
-            filter: { _id: { $in: request.ids } },
+            filter: { id: { $in: request.ids } },
             ...request.options
         });
     }
diff --git a/packages/plugins/driver-memory/src/memory-matcher.ts b/packages/plugins/driver-memory/src/memory-matcher.ts
index f7a7d1acf..3957e3366 100644
--- a/packages/plugins/driver-memory/src/memory-matcher.ts
+++ b/packages/plugins/driver-memory/src/memory-matcher.ts
@@ -62,11 +62,6 @@ export function match(record: RecordType, filter: any): boolean {
  * Access nested properties via dot-notation (e.g. "user.name")
  */
 export function getValueByPath(obj: any, path: string): any {
-    // Compatibility: Map _id to id if _id is missing
-    if (path === '_id' && obj._id === undefined && obj.id !== undefined) {
-        return obj.id;
-    }
-
     if (!path.includes('.')) return obj[path];
     return path.split('.').reduce((o, i) => (o ? o[i] : undefined), obj);
 }
diff --git a/packages/rest/src/rest.test.ts b/packages/rest/src/rest.test.ts
index e69d8c40b..12cc1586f 100644
--- a/packages/rest/src/rest.test.ts
+++ b/packages/rest/src/rest.test.ts
@@ -445,7 +445,7 @@ describe('RestServer', () => {
       protocol.getData.mockResolvedValue({
         object: 'order_item',
         id: 'oi_123',
-        record: { _id: 'oi_123', name: 'Item 1' },
+        record: { id: 'oi_123', name: 'Item 1' },
       });
 
       await getByIdRoute!.handler(mockReq, mockRes);
@@ -478,7 +478,7 @@ describe('RestServer', () => {
       protocol.getData.mockResolvedValue({
         object: 'contact',
         id: 'c_1',
-        record: { _id: 'c_1' },
+        record: { id: 'c_1' },
       });
 
       await getByIdRoute!.handler(mockReq, mockRes);
diff --git a/packages/runtime/src/http-dispatcher.test.ts b/packages/runtime/src/http-dispatcher.test.ts
index 7ae993583..3e2466757 100644
--- a/packages/runtime/src/http-dispatcher.test.ts
+++ b/packages/runtime/src/http-dispatcher.test.ts
@@ -600,7 +600,7 @@ describe('HttpDispatcher', () => {
 
     describe('handleData', () => {
         it('should pass expand and select to broker for GET /data/:object/:id', async () => {
-            mockBroker.call.mockResolvedValue({ object: 'order_item', id: 'oi_1', record: { _id: 'oi_1' } });
+            mockBroker.call.mockResolvedValue({ object: 'order_item', id: 'oi_1', record: { id: 'oi_1' } });
 
             const result = await dispatcher.handleData(
                 '/order_item/oi_1', 'GET', {},
diff --git a/packages/spec/DEVELOPMENT_PLAN.md b/packages/spec/DEVELOPMENT_PLAN.md
index 2b331f267..13a21f471 100644
--- a/packages/spec/DEVELOPMENT_PLAN.md
+++ b/packages/spec/DEVELOPMENT_PLAN.md
@@ -232,7 +232,7 @@ export const MetricType = z.enum(['counter', 'gauge', 'histogram', 'summary']);
 
 ```typescript
 // Before (snake_case — violates camelCase property key rule)
-_id: z.string(),
+id: z.string(),
 created_by: z.string(),
 created_at: z.string().datetime(),
 updated_by: z.string(),
diff --git a/packages/spec/docs/SYNC_ARCHITECTURE.md b/packages/spec/docs/SYNC_ARCHITECTURE.md
index 36b5f217e..44298a91f 100644
--- a/packages/spec/docs/SYNC_ARCHITECTURE.md
+++ b/packages/spec/docs/SYNC_ARCHITECTURE.md
@@ -258,7 +258,7 @@ const sapConnector: Connector = {
     direction: 'bidirectional',
     schedule: '*/15 * * * *', // Every 15 minutes
     realtimeSync: true,
-    timestampField: 'last_modified_at',
+    timestampField: 'updated_at',
     conflictResolution: 'latest_wins',
     batchSize: 1000,
     deleteMode: 'soft_delete'
diff --git a/packages/spec/src/data/dataset.zod.ts b/packages/spec/src/data/dataset.zod.ts
index 4fd8a6ec6..1b98d4937 100644
--- a/packages/spec/src/data/dataset.zod.ts
+++ b/packages/spec/src/data/dataset.zod.ts
@@ -34,7 +34,7 @@ export const DatasetSchema = z.object({
    * Idempotency Key (The "Upsert" Key)
    * The field used to check if a record already exists.
    * Best Practice: Use a natural key like 'code', 'slug', 'username' or 'external_id'.
-   * Standard: '_id' (internal ID) is rarely used for portable seed data.
+   * Standard: 'id' is rarely used for portable seed data — prefer natural keys.
    */
   externalId: z.string().default('name').describe('Field match for uniqueness check'),
 
diff --git a/packages/spec/src/data/mapping.test.ts b/packages/spec/src/data/mapping.test.ts
index 9fb69bbfb..6e96bf417 100644
--- a/packages/spec/src/data/mapping.test.ts
+++ b/packages/spec/src/data/mapping.test.ts
@@ -95,7 +95,7 @@ describe('FieldMappingSchema', () => {
       params: {
         object: 'account',
         fromField: 'name',
-        toField: '_id',
+        toField: 'id',
         autoCreate: false
       }
     });
@@ -103,7 +103,7 @@ describe('FieldMappingSchema', () => {
     expect(mapping.transform).toBe('lookup');
     expect(mapping.params?.object).toBe('account');
     expect(mapping.params?.fromField).toBe('name');
-    expect(mapping.params?.toField).toBe('_id');
+    expect(mapping.params?.toField).toBe('id');
   });
 
   it('should accept map transform', () => {
@@ -297,7 +297,7 @@ describe('MappingSchema', () => {
       fieldMapping: [{ source: 'email', target: 'email' }],
       extractQuery: {
         object: 'contact',
-        fields: ['_id', 'email', 'name'],
+        fields: ['id', 'email', 'name'],
         filters: ['status', '=', 'active']
       }
     });
@@ -361,7 +361,7 @@ describe('MappingSchema', () => {
           params: {
             object: 'account',
             fromField: 'name',
-            toField: '_id'
+            toField: 'id'
           }
         },
         {
diff --git a/packages/spec/src/data/mapping.zod.ts b/packages/spec/src/data/mapping.zod.ts
index 6268e3ede..fca399a23 100644
--- a/packages/spec/src/data/mapping.zod.ts
+++ b/packages/spec/src/data/mapping.zod.ts
@@ -39,7 +39,7 @@ export const FieldMappingSchema = z.object({
     // Lookup
     object: z.string().optional(), // Lookup Object
     fromField: z.string().optional(), // Match on (e.g. "name")
-    toField: z.string().optional(), // Value to take (e.g. "_id")
+    toField: z.string().optional(), // Value to take (e.g. "id")
     autoCreate: z.boolean().optional(), // Create if missing
     
     // Map
diff --git a/packages/spec/src/integration/connector/database.zod.ts b/packages/spec/src/integration/connector/database.zod.ts
index b6ee2a165..bf103662b 100644
--- a/packages/spec/src/integration/connector/database.zod.ts
+++ b/packages/spec/src/integration/connector/database.zod.ts
@@ -277,7 +277,7 @@ export const mongoConnectorExample = {
       name: 'event',
       label: 'Event',
       tableName: 'events',
-      primaryKey: '_id',
+      primaryKey: 'id',
       enabled: true,
     },
   ],
diff --git a/packages/spec/src/qa/testing.test.ts b/packages/spec/src/qa/testing.test.ts
index c84a81c71..1087d484e 100644
--- a/packages/spec/src/qa/testing.test.ts
+++ b/packages/spec/src/qa/testing.test.ts
@@ -115,8 +115,8 @@ describe('TestStepSchema', () => {
     const step = {
       ...minimalStep,
       description: 'Creates a new account record',
-      assertions: [{ field: 'body._id', operator: 'not_null', expectedValue: null }],
-      capture: { newId: 'body._id' },
+      assertions: [{ field: 'body.id', operator: 'not_null', expectedValue: null }],
+      capture: { newId: 'body.id' },
     };
     expect(() => TestStepSchema.parse(step)).not.toThrow();
   });
diff --git a/packages/spec/src/qa/testing.zod.ts b/packages/spec/src/qa/testing.zod.ts
index 6084aae6d..f600216fa 100644
--- a/packages/spec/src/qa/testing.zod.ts
+++ b/packages/spec/src/qa/testing.zod.ts
@@ -54,7 +54,7 @@ export const TestStepSchema = z.object({
   action: TestActionSchema.describe('The action to execute in this step'),
   assertions: z.array(TestAssertionSchema).optional().describe('Assertions to validate after the action completes'),
   // Capture outputs to variables for subsequent steps
-  capture: z.record(z.string(), z.string()).optional().describe('Map result fields to context variables: { "newId": "body._id" }')
+  capture: z.record(z.string(), z.string()).optional().describe('Map result fields to context variables: { "newId": "body.id" }')
 }).describe('A single step in a test scenario, consisting of an action and optional assertions');
 
 export const TestScenarioSchema = z.object({