diff --git a/.changeset/27028-data-engine-rpc-protocol-retired.md b/.changeset/27028-data-engine-rpc-protocol-retired.md
new file mode 100644
index 00000000000..1a565ea4a8e
--- /dev/null
+++ b/.changeset/27028-data-engine-rpc-protocol-retired.md
@@ -0,0 +1,28 @@
+---
+'@objectstack/spec': minor
+'@objectstack/objectql': patch
+---
+
+feat(spec)!: retire the unserved Virtual ObjectQL request protocol from `data/data-engine.zod.ts`
+
+Clause-②: no (narrowing)
+Metadata-protocol: narrowed
+
+<!-- adr-0087: registered data-engine-rpc-protocol-retired -->
+
+**BREAKING** for TypeScript and JSON Schema consumers of one block that nothing ever served. `@objectstack/spec/data` published a serialized request protocol for a "Virtual Data Engine" in another process: `DataEngineRequestSchema` and its nine `method` arms, plus `DataEngineContractSchema`. No such engine existed and nothing parsed the protocol. A census found no importer or parser in this repo outside the defining module, and zero hits in hotcrm, objectui and docs.objectos.ai. As published it was also unsafe to implement: every arm admitted a caller-supplied `context` (`isSystem` included), and the `execute` arm carried a raw driver command. The whole block is retired (ADR-0049 enforce-or-remove, by the maintainer's ruling A).
+
+| FROM | TO |
+|:--|:--|
+| `DataEngineFindRequestSchema`, `DataEngineFindOneRequestSchema`, `DataEngineCountRequestSchema`, `DataEngineAggregateRequestSchema` | in process, `IDataEngine.find` / `findOne` / `count` / `aggregate` with `EngineQueryOptions` / `EngineCountOptions` / `EngineAggregateOptions`; over the wire, the REST data routes (`/data/:object`, `POST /data/:object/query`) |
+| `DataEngineInsertRequestSchema`, `DataEngineUpdateRequestSchema`, `DataEngineDeleteRequestSchema` | `IDataEngine.insert` / `update` / `delete` with `DataEngineInsertOptions` / `EngineUpdateOptions` / `EngineDeleteOptions`; over the wire, the REST data routes, and `POST {basePath}/batch` for a batch |
+| `DataEngineVectorFindRequestSchema`, `DataEngineExecuteRequestSchema` | `IDataEngine.vectorFind?` / `execute?`, in process only |
+| `DataEngineRequestSchema` and the types `DataEngineRequest`, `DataEngineRequestParsed`, `DataEngineExecuteRequest`, `DataEngineInsertRequest`, `DataEngineVectorFindRequest` | none: there is no serialized engine-call protocol; call `IDataEngine` in process, or a hook or action body's `ctx.api.object(name)` |
+| `DataEngineContractSchema` | the `IDataEngine` interface (`@objectstack/spec/contracts`) |
+
+The one-line fix: replace an import of any name above with the `IDataEngine` method or option type in the right-hand column. An import left behind is `TS2305` after upgrade.
+
+The retirement kit:
+
+- **`@objectstack/spec`**: the ten request schemas, `DataEngineContractSchema`, the five types and their private helpers (`RpcQueryOptionsSchema` and the `filter`-only fold) are deleted. The ten published defs `data/DataEngineRequest` and `data/DataEngine{Find,FindOne,Insert,Update,Delete,Count,Aggregate,Execute,VectorFind}Request` leave `json-schema/` and the reference docs, registered in `RETIRED_DEFS_BY_MAJOR[18]`, and the D3 entry `data-engine-rpc-protocol-retired` names the doors that exist. There is no `retiredKey()` tombstone and no conversion: no metadata source authors these shapes, and no parse remains for a prescription to reach. `IDataEngine`, every `*OptionsSchema`, `RPC_QUERY_ALIAS_SLOTS`, `foldQueryAliasSlots` and the query-transport schemas are unchanged. Runtime behaviour is unchanged.
+- **`@objectstack/objectql`**: a comment that named `RpcQueryOptionsSchema` now names `QueryWithTransportSchema`. No behaviour changes.
diff --git a/content/docs/kernel/contracts/data-engine.mdx b/content/docs/kernel/contracts/data-engine.mdx
index b2db312eaca..d46b76d2878 100644
--- a/content/docs/kernel/contracts/data-engine.mdx
+++ b/content/docs/kernel/contracts/data-engine.mdx
@@ -27,7 +27,6 @@ import type {
   EngineDeleteOptions,
   EngineAggregateOptions,
   EngineCountOptions,
-  DataEngineRequest,
 } from '@objectstack/spec/data';
 
 export interface IDataEngine {
@@ -48,9 +47,6 @@ export interface IDataEngine {
     where?: any; limit?: number; fields?: string[]; threshold?: number;
   }): Promise<any[]>;
 
-  // Batch Operations (optional, transactional)
-  batch?(requests: DataEngineRequest[], options?: { transaction?: boolean }): Promise<any[]>;
-
   // Raw Command Escape Hatch (optional)
   execute?(command: any, options?: Record<string, any>): Promise<any>;
 
@@ -470,8 +466,8 @@ declares one; none carries a `readonly` policy of its own any more — see
 <Callout type="warn">
 `WriteObservabilityOptions` is a **TS-contract-level, in-process-only** bag —
 all three members. It is deliberately not part of the serializable Zod options schemas:
-a function is unrepresentable in JSON Schema and cannot cross the RPC (Virtual
-Data Engine) boundary, so remote callers never receive these events; and putting
+a function is unrepresentable in JSON Schema and cannot be serialized, so remote
+callers (REST, the client SDK) never receive these events; and putting
 `strictReadonlyWrites` in the serializable bag would let any client toggle
 write-refusal on a security-adjacent path (#5126 ruling). A remote caller can set
 none of the three, and for the strips it gets NEITHER behaviour: its write is
@@ -569,17 +565,12 @@ const results = await engine.vectorFind?.('document', embeddingVector, {
 });
 ```
 
-### batch (Transactional)
-
-Execute multiple operations in a single transaction:
+### Several writes, atomically
 
-```typescript
-const results = await engine.batch?.([
-  { method: 'insert', object: 'project', data: { name: 'Website Redesign', status: 'active' } },
-  { method: 'insert', object: 'task', data: { title: 'Design mockups', status: 'open' } },
-  { method: 'insert', object: 'task', data: { title: 'Implement frontend', status: 'open' } },
-], { transaction: true });
-```
+There is no `batch` member: it was never implemented by any engine and was retired
+(ADR-0119 D3). In process, wrap the writes in `IObjectQLEngine.transaction(cb)`;
+for a batch over one object use the metadata protocol's `batchData` with
+`options.atomic: true`; over the wire, `POST {basePath}/batch`.
 
 ### execute (Raw Command)
 
@@ -624,7 +615,7 @@ detection locate drivers.
 <Callout type="warn">
 **Deprecated Parameter Names**
 
-The following legacy parameter names are accepted by the RPC layer for backward compatibility but should **not** be used in new code. The protocol normalizer resolves conflicts with canonical names taking precedence.
+The following legacy parameter names are accepted on the wire (the protocol normalizer) for backward compatibility but should **not** be used in new code. The protocol normalizer resolves conflicts with canonical names taking precedence.
 
 | Legacy (Deprecated) | Canonical | Notes |
 |:---------------------|:----------|:------|
diff --git a/content/docs/references/data/data-engine.mdx b/content/docs/references/data/data-engine.mdx
index 88923ae3886..29b40bcf46a 100644
--- a/content/docs/references/data/data-engine.mdx
+++ b/content/docs/references/data/data-engine.mdx
@@ -22,8 +22,8 @@ The Data Engine acts as the "Driver" layer in the Hexagonal Architecture.
 ## TypeScript Usage
 
 ```typescript
-import { BaseEngineOptionsSchema, DataEngineAggregateOptionsSchema, DataEngineAggregateRequestSchema, DataEngineCountOptionsSchema, DataEngineCountRequestSchema, DataEngineDeleteOptionsSchema, DataEngineDeleteRequestSchema, DataEngineExecuteRequestSchema, DataEngineFilterSchema, DataEngineFindOneRequestSchema, DataEngineFindRequestSchema, DataEngineInsertOptionsSchema, DataEngineInsertRequestSchema, DataEngineQueryOptionsSchema, DataEngineRequestSchema, DataEngineSortSchema, DataEngineUpdateOptionsSchema, DataEngineUpdateRequestSchema, DataEngineVectorFindRequestSchema, DroppedFieldsEventSchema, EngineAggregateOptionsSchema, EngineCountOptionsSchema, EngineDeleteOptionsSchema, EngineQueryOptionsSchema, EngineUpdateOptionsSchema, QueryPageWindowSchema, QueryPageWindowParamSchema, QueryTransportParamsSchema, QueryWithTransportSchema, ValidationAdvisoryEventSchema } from '@objectstack/spec/data';
-import type { BaseEngineOptions, DataEngineAggregateOptions, DataEngineCountOptions, DataEngineDeleteOptions, DataEngineExecuteRequest, DataEngineFilter, DataEngineInsertOptions, DataEngineInsertRequest, DataEngineQueryOptions, DataEngineRequest, DataEngineSort, DataEngineUpdateOptions, DataEngineVectorFindRequest, DroppedFieldsEvent, EngineAggregateOptions, EngineCountOptions, EngineDeleteOptions, EngineQueryOptions, EngineUpdateOptions, QueryPageWindow, QueryPageWindowParam, QueryTransportParams, QueryWithTransport, ValidationAdvisoryEvent } from '@objectstack/spec/data';
+import { BaseEngineOptionsSchema, DataEngineAggregateOptionsSchema, DataEngineCountOptionsSchema, DataEngineDeleteOptionsSchema, DataEngineFilterSchema, DataEngineInsertOptionsSchema, DataEngineQueryOptionsSchema, DataEngineSortSchema, DataEngineUpdateOptionsSchema, DroppedFieldsEventSchema, EngineAggregateOptionsSchema, EngineCountOptionsSchema, EngineDeleteOptionsSchema, EngineQueryOptionsSchema, EngineUpdateOptionsSchema, QueryPageWindowSchema, QueryPageWindowParamSchema, QueryTransportParamsSchema, QueryWithTransportSchema, ValidationAdvisoryEventSchema } from '@objectstack/spec/data';
+import type { BaseEngineOptions, DataEngineAggregateOptions, DataEngineCountOptions, DataEngineDeleteOptions, DataEngineFilter, DataEngineInsertOptions, DataEngineQueryOptions, DataEngineSort, DataEngineUpdateOptions, DroppedFieldsEvent, EngineAggregateOptions, EngineCountOptions, EngineDeleteOptions, EngineQueryOptions, EngineUpdateOptions, QueryPageWindow, QueryPageWindowParam, QueryTransportParams, QueryWithTransport, ValidationAdvisoryEvent } from '@objectstack/spec/data';
 
 // Validate data
 const result = BaseEngineOptionsSchema.parse(data);
@@ -132,33 +132,6 @@ Options for DataEngine.aggregate operations
 | **traceId** | `string` | optional |  |
 
 
----
-
-## DataEngineAggregateRequest
-
-### Properties
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **method** | `'aggregate'` | ✅ |  |
-| **object** | `string` | ✅ |  |
-| **query** | `{ context?: object; where?: Record<string, any> \| any; groupBy?: (string \| object)[]; aggregations?: object[]; … }` | ✅ |  |
-
-### Nested Shape: `DataEngineAggregateRequest.query`
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **context** | `{ userId?: string; actor?: string; attributedUserId?: string; email?: string; … }` | optional |  |
-| **where** | `Record<string, any> \| any` | optional |  |
-| **groupBy** | `(string \| { field: string; dateGranularity?: Enum<'day' \| 'week' \| 'month' \| 'quarter' \| 'year'>; alias?: string })[]` | optional | GROUP BY targets (strings or `{field, dateGranularity?}` objects for date bucketing) |
-| **aggregations** | `{ function: Enum<'count' \| 'sum' \| 'avg' \| 'min' \| 'max' \| 'count_distinct'>; field?: string; alias: string; filter?: any }[]` | optional |  |
-| **having** | `any` | optional | HAVING — filter over the aggregated rows (aggregation aliases + groupBy projections); applied engine-side after aggregation |
-| **timezone** | `string` | optional |  |
-| **search** | `string \| { query: string; fields?: string[]; fuzzy?: boolean; operator?: Enum<'and' \| 'or'>; … }` | optional |  |
-| **searchFields** | `string[]` | optional |  |
-| **filter** | `Record<string, any> \| any` | optional | Data Engine query filter conditions |
-
-
 ---
 
 ## DataEngineCountOptions
@@ -211,29 +184,6 @@ Options for DataEngine.count operations
 | **traceId** | `string` | optional |  |
 
 
----
-
-## DataEngineCountRequest
-
-### Properties
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **method** | `'count'` | ✅ |  |
-| **object** | `string` | ✅ |  |
-| **query** | `{ context?: object; where?: Record<string, any> \| any; search?: string \| object; searchFields?: string[]; … }` | optional |  |
-
-### Nested Shape: `DataEngineCountRequest.query`
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **context** | `{ userId?: string; actor?: string; attributedUserId?: string; email?: string; … }` | optional |  |
-| **where** | `Record<string, any> \| any` | optional |  |
-| **search** | `string \| { query: string; fields?: string[]; fuzzy?: boolean; operator?: Enum<'and' \| 'or'>; … }` | optional |  |
-| **searchFields** | `string[]` | optional |  |
-| **filter** | `Record<string, any> \| any` | optional | Data Engine query filter conditions |
-
-
 ---
 
 ## DataEngineDeleteOptions
@@ -287,42 +237,6 @@ Options for DataEngine.delete operations
 | **traceId** | `string` | optional |  |
 
 
----
-
-## DataEngineDeleteRequest
-
-### Properties
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **method** | `'delete'` | ✅ |  |
-| **object** | `string` | ✅ |  |
-| **id** | `string \| number` | optional | ID for single delete, or use where in options |
-| **options** | `{ context?: object; where?: Record<string, any> \| any; multi?: boolean; filter?: Record<string, any> \| any }` | optional |  |
-
-### Nested Shape: `DataEngineDeleteRequest.options`
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **context** | `{ userId?: string; actor?: string; attributedUserId?: string; email?: string; … }` | optional |  |
-| **where** | `Record<string, any> \| any` | optional |  |
-| **multi** | `boolean` | optional (default: `false`) |  |
-| **filter** | `Record<string, any> \| any` | optional | Data Engine query filter conditions |
-
-
----
-
-## DataEngineExecuteRequest
-
-### Properties
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **method** | `'execute'` | ✅ |  |
-| **command** | `any` | ✅ |  |
-| **options** | `Record<string, any>` | optional |  |
-
-
 ---
 
 ## DataEngineFilter
@@ -346,76 +260,6 @@ Reference: any
 ---
 
 
----
-
-## DataEngineFindOneRequest
-
-### Properties
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **method** | `'findOne'` | ✅ |  |
-| **object** | `string` | ✅ |  |
-| **query** | `{ context?: object; where?: Record<string, any> \| any; fields?: string[]; orderBy?: object[]; … }` | optional |  |
-
-### Nested Shape: `DataEngineFindOneRequest.query`
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **context** | `{ userId?: string; actor?: string; attributedUserId?: string; email?: string; … }` | optional |  |
-| **where** | `Record<string, any> \| any` | optional |  |
-| **fields** | `string[]` | optional |  |
-| **orderBy** | `{ field: string; order?: Enum<'asc' \| 'desc'> }[]` | optional |  |
-| **limit** | `number` | optional |  |
-| **offset** | `number` | optional |  |
-| **top** | `number` | optional |  |
-| **cursor** | `never` | optional | [REMOVED] `query.cursor` was removed in @objectstack/spec 17 (ADR-0049) — no driver ever implemented keyset pagination, so the cursor was accepted and ignored and every page came back identical (a caller looping "until hasMore is false" never terminates). Delete the key; `QueryBuilder.cursor()` was removed with it. Express the keyset as an ordinary `where` predicate on your sort key — `where: { created_at: { $gt: last.created_at } }` with the matching `orderBy` — which every driver executes with canonicalised comparands. A first-class cursor, if ever built, will be a response-minted opaque token, not this caller-built record. |
-| **search** | `string \| { query: string; fields?: string[]; fuzzy?: boolean; operator?: Enum<'and' \| 'or'>; … }` | optional |  |
-| **searchFields** | `string[]` | optional |  |
-| **expand** | `Record<string, { object: string; fields?: string[]; where?: any; search?: string \| object; … }>` | optional |  |
-| **distinct** | `never` | optional | [REMOVED] `query.distinct` was removed in @objectstack/spec 17 (ADR-0049 / ADR-0078) — no driver ever rendered SELECT DISTINCT; the flag's only observable effect was MIS-WIRED: the REST list path treated a distinct query as not countable and silently degraded `total`/`hasMore` to a page-local estimate while still returning duplicate rows. Delete the key; `QueryBuilder.distinct()` was removed with it, and the count suppression is gone (`total` is truthful again). For unique values of one column use the SQL/memory drivers' `distinct(object, field)` door; for unique combinations, `groupBy`; for a deduplicated count, the `count_distinct` aggregation. |
-| **filter** | `Record<string, any> \| any` | optional | Data Engine query filter conditions |
-| **select** | `string[]` | optional |  |
-| **sort** | `Record<string, Enum<'asc' \| 'desc'>> \| Record<string, 1 \| -1> \| { field: string; order?: Enum<'asc' \| 'desc'> }[]` | optional | Sort order definition |
-| **skip** | `integer` | optional |  |
-| **populate** | `string[]` | optional |  |
-
-
----
-
-## DataEngineFindRequest
-
-### Properties
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **method** | `'find'` | ✅ |  |
-| **object** | `string` | ✅ |  |
-| **query** | `{ context?: object; where?: Record<string, any> \| any; fields?: string[]; orderBy?: object[]; … }` | optional |  |
-
-### Nested Shape: `DataEngineFindRequest.query`
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **context** | `{ userId?: string; actor?: string; attributedUserId?: string; email?: string; … }` | optional |  |
-| **where** | `Record<string, any> \| any` | optional |  |
-| **fields** | `string[]` | optional |  |
-| **orderBy** | `{ field: string; order?: Enum<'asc' \| 'desc'> }[]` | optional |  |
-| **limit** | `number` | optional |  |
-| **offset** | `number` | optional |  |
-| **top** | `number` | optional |  |
-| **cursor** | `never` | optional | [REMOVED] `query.cursor` was removed in @objectstack/spec 17 (ADR-0049) — no driver ever implemented keyset pagination, so the cursor was accepted and ignored and every page came back identical (a caller looping "until hasMore is false" never terminates). Delete the key; `QueryBuilder.cursor()` was removed with it. Express the keyset as an ordinary `where` predicate on your sort key — `where: { created_at: { $gt: last.created_at } }` with the matching `orderBy` — which every driver executes with canonicalised comparands. A first-class cursor, if ever built, will be a response-minted opaque token, not this caller-built record. |
-| **search** | `string \| { query: string; fields?: string[]; fuzzy?: boolean; operator?: Enum<'and' \| 'or'>; … }` | optional |  |
-| **searchFields** | `string[]` | optional |  |
-| **expand** | `Record<string, { object: string; fields?: string[]; where?: any; search?: string \| object; … }>` | optional |  |
-| **distinct** | `never` | optional | [REMOVED] `query.distinct` was removed in @objectstack/spec 17 (ADR-0049 / ADR-0078) — no driver ever rendered SELECT DISTINCT; the flag's only observable effect was MIS-WIRED: the REST list path treated a distinct query as not countable and silently degraded `total`/`hasMore` to a page-local estimate while still returning duplicate rows. Delete the key; `QueryBuilder.distinct()` was removed with it, and the count suppression is gone (`total` is truthful again). For unique values of one column use the SQL/memory drivers' `distinct(object, field)` door; for unique combinations, `groupBy`; for a deduplicated count, the `count_distinct` aggregation. |
-| **filter** | `Record<string, any> \| any` | optional | Data Engine query filter conditions |
-| **select** | `string[]` | optional |  |
-| **sort** | `Record<string, Enum<'asc' \| 'desc'>> \| Record<string, 1 \| -1> \| { field: string; order?: Enum<'asc' \| 'desc'> }[]` | optional | Sort order definition |
-| **skip** | `integer` | optional |  |
-| **populate** | `string[]` | optional |  |
-
-
 ---
 
 ## DataEngineInsertOptions
@@ -468,20 +312,6 @@ Options for DataEngine.insert operations
 | **traceId** | `string` | optional |  |
 
 
----
-
-## DataEngineInsertRequest
-
-### Properties
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **method** | `'insert'` | ✅ |  |
-| **object** | `string` | ✅ |  |
-| **data** | `Record<string, any> \| Record<string, any>[]` | ✅ |  |
-| **options** | `{ context?: object; returning?: boolean }` | optional | Options for DataEngine.insert operations |
-
-
 ---
 
 ## DataEngineQueryOptions
@@ -540,221 +370,6 @@ Query options for IDataEngine.find() operations
 | **traceId** | `string` | optional |  |
 
 
----
-
-## DataEngineRequest
-
-Virtual ObjectQL Request Protocol
-
-### Union Options
-
-This schema accepts one of the following structures:
-
-#### Option 1
-
-### Properties
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **method** | `'find'` | ✅ |  |
-| **object** | `string` | ✅ |  |
-| **query** | `{ context?: object; where?: Record<string, any> \| any; fields?: string[]; orderBy?: object[]; … }` | optional |  |
-
-### Nested Shape: `DataEngineRequest[method='find'].query`
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **context** | `{ userId?: string; actor?: string; attributedUserId?: string; email?: string; … }` | optional |  |
-| **where** | `Record<string, any> \| any` | optional |  |
-| **fields** | `string[]` | optional |  |
-| **orderBy** | `{ field: string; order?: Enum<'asc' \| 'desc'> }[]` | optional |  |
-| **limit** | `number` | optional |  |
-| **offset** | `number` | optional |  |
-| **top** | `number` | optional |  |
-| **cursor** | `never` | optional | [REMOVED] `query.cursor` was removed in @objectstack/spec 17 (ADR-0049) — no driver ever implemented keyset pagination, so the cursor was accepted and ignored and every page came back identical (a caller looping "until hasMore is false" never terminates). Delete the key; `QueryBuilder.cursor()` was removed with it. Express the keyset as an ordinary `where` predicate on your sort key — `where: { created_at: { $gt: last.created_at } }` with the matching `orderBy` — which every driver executes with canonicalised comparands. A first-class cursor, if ever built, will be a response-minted opaque token, not this caller-built record. |
-| **search** | `string \| { query: string; fields?: string[]; fuzzy?: boolean; operator?: Enum<'and' \| 'or'>; … }` | optional |  |
-| **searchFields** | `string[]` | optional |  |
-| **expand** | `Record<string, { object: string; fields?: string[]; where?: any; search?: string \| object; … }>` | optional |  |
-| **distinct** | `never` | optional | [REMOVED] `query.distinct` was removed in @objectstack/spec 17 (ADR-0049 / ADR-0078) — no driver ever rendered SELECT DISTINCT; the flag's only observable effect was MIS-WIRED: the REST list path treated a distinct query as not countable and silently degraded `total`/`hasMore` to a page-local estimate while still returning duplicate rows. Delete the key; `QueryBuilder.distinct()` was removed with it, and the count suppression is gone (`total` is truthful again). For unique values of one column use the SQL/memory drivers' `distinct(object, field)` door; for unique combinations, `groupBy`; for a deduplicated count, the `count_distinct` aggregation. |
-| **filter** | `Record<string, any> \| any` | optional | Data Engine query filter conditions |
-| **select** | `string[]` | optional |  |
-| **sort** | `Record<string, Enum<'asc' \| 'desc'>> \| Record<string, 1 \| -1> \| { field: string; order?: Enum<'asc' \| 'desc'> }[]` | optional | Sort order definition |
-| **skip** | `integer` | optional |  |
-| **populate** | `string[]` | optional |  |
-
----
-
-#### Option 2
-
-### Properties
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **method** | `'findOne'` | ✅ |  |
-| **object** | `string` | ✅ |  |
-| **query** | `{ context?: object; where?: Record<string, any> \| any; fields?: string[]; orderBy?: object[]; … }` | optional |  |
-
-### Nested Shape: `DataEngineRequest[method='findOne'].query`
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **context** | `{ userId?: string; actor?: string; attributedUserId?: string; email?: string; … }` | optional |  |
-| **where** | `Record<string, any> \| any` | optional |  |
-| **fields** | `string[]` | optional |  |
-| **orderBy** | `{ field: string; order?: Enum<'asc' \| 'desc'> }[]` | optional |  |
-| **limit** | `number` | optional |  |
-| **offset** | `number` | optional |  |
-| **top** | `number` | optional |  |
-| **cursor** | `never` | optional | [REMOVED] `query.cursor` was removed in @objectstack/spec 17 (ADR-0049) — no driver ever implemented keyset pagination, so the cursor was accepted and ignored and every page came back identical (a caller looping "until hasMore is false" never terminates). Delete the key; `QueryBuilder.cursor()` was removed with it. Express the keyset as an ordinary `where` predicate on your sort key — `where: { created_at: { $gt: last.created_at } }` with the matching `orderBy` — which every driver executes with canonicalised comparands. A first-class cursor, if ever built, will be a response-minted opaque token, not this caller-built record. |
-| **search** | `string \| { query: string; fields?: string[]; fuzzy?: boolean; operator?: Enum<'and' \| 'or'>; … }` | optional |  |
-| **searchFields** | `string[]` | optional |  |
-| **expand** | `Record<string, { object: string; fields?: string[]; where?: any; search?: string \| object; … }>` | optional |  |
-| **distinct** | `never` | optional | [REMOVED] `query.distinct` was removed in @objectstack/spec 17 (ADR-0049 / ADR-0078) — no driver ever rendered SELECT DISTINCT; the flag's only observable effect was MIS-WIRED: the REST list path treated a distinct query as not countable and silently degraded `total`/`hasMore` to a page-local estimate while still returning duplicate rows. Delete the key; `QueryBuilder.distinct()` was removed with it, and the count suppression is gone (`total` is truthful again). For unique values of one column use the SQL/memory drivers' `distinct(object, field)` door; for unique combinations, `groupBy`; for a deduplicated count, the `count_distinct` aggregation. |
-| **filter** | `Record<string, any> \| any` | optional | Data Engine query filter conditions |
-| **select** | `string[]` | optional |  |
-| **sort** | `Record<string, Enum<'asc' \| 'desc'>> \| Record<string, 1 \| -1> \| { field: string; order?: Enum<'asc' \| 'desc'> }[]` | optional | Sort order definition |
-| **skip** | `integer` | optional |  |
-| **populate** | `string[]` | optional |  |
-
----
-
-#### Option 3
-
-### Properties
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **method** | `'insert'` | ✅ |  |
-| **object** | `string` | ✅ |  |
-| **data** | `Record<string, any> \| Record<string, any>[]` | ✅ |  |
-| **options** | `{ context?: object; returning?: boolean }` | optional | Options for DataEngine.insert operations |
-
----
-
-#### Option 4
-
-### Properties
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **method** | `'update'` | ✅ |  |
-| **object** | `string` | ✅ |  |
-| **data** | `Record<string, any>` | ✅ |  |
-| **id** | `string \| number` | optional | ID for single update, or use where in options |
-| **options** | `{ context?: object; where?: Record<string, any> \| any; multi?: boolean; returning?: boolean; … }` | optional |  |
-
-### Nested Shape: `DataEngineRequest[method='update'].options`
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **context** | `{ userId?: string; actor?: string; attributedUserId?: string; email?: string; … }` | optional |  |
-| **where** | `Record<string, any> \| any` | optional |  |
-| **upsert** | `never` | optional | [REMOVED] `update.options.upsert` was removed in @objectstack/spec 17 (ADR-0049) — it was declared and allowlisted but never implemented: no engine or driver path ever read it, so `{ upsert: true }` was accepted and silently dropped and the update stayed a plain update. Delete the key. Express create-if-absent explicitly: a by-id update whose id names no row throws RECORD_NOT_FOUND (the by-id not-found gate) rather than inserting, so read the row first (`findOne`) and call `insert` or `update` on what you find. A first-class upsert, if ever built, must reconcile with that gate by design rather than through this silent flag. |
-| **multi** | `boolean` | optional (default: `false`) |  |
-| **returning** | `boolean` | optional (default: `false`) |  |
-| **filter** | `Record<string, any> \| any` | optional | Data Engine query filter conditions |
-
----
-
-#### Option 5
-
-### Properties
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **method** | `'delete'` | ✅ |  |
-| **object** | `string` | ✅ |  |
-| **id** | `string \| number` | optional | ID for single delete, or use where in options |
-| **options** | `{ context?: object; where?: Record<string, any> \| any; multi?: boolean; filter?: Record<string, any> \| any }` | optional |  |
-
-### Nested Shape: `DataEngineRequest[method='delete'].options`
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **context** | `{ userId?: string; actor?: string; attributedUserId?: string; email?: string; … }` | optional |  |
-| **where** | `Record<string, any> \| any` | optional |  |
-| **multi** | `boolean` | optional (default: `false`) |  |
-| **filter** | `Record<string, any> \| any` | optional | Data Engine query filter conditions |
-
----
-
-#### Option 6
-
-### Properties
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **method** | `'count'` | ✅ |  |
-| **object** | `string` | ✅ |  |
-| **query** | `{ context?: object; where?: Record<string, any> \| any; search?: string \| object; searchFields?: string[]; … }` | optional |  |
-
-### Nested Shape: `DataEngineRequest[method='count'].query`
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **context** | `{ userId?: string; actor?: string; attributedUserId?: string; email?: string; … }` | optional |  |
-| **where** | `Record<string, any> \| any` | optional |  |
-| **search** | `string \| { query: string; fields?: string[]; fuzzy?: boolean; operator?: Enum<'and' \| 'or'>; … }` | optional |  |
-| **searchFields** | `string[]` | optional |  |
-| **filter** | `Record<string, any> \| any` | optional | Data Engine query filter conditions |
-
----
-
-#### Option 7
-
-### Properties
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **method** | `'aggregate'` | ✅ |  |
-| **object** | `string` | ✅ |  |
-| **query** | `{ context?: object; where?: Record<string, any> \| any; groupBy?: (string \| object)[]; aggregations?: object[]; … }` | ✅ |  |
-
-### Nested Shape: `DataEngineRequest[method='aggregate'].query`
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **context** | `{ userId?: string; actor?: string; attributedUserId?: string; email?: string; … }` | optional |  |
-| **where** | `Record<string, any> \| any` | optional |  |
-| **groupBy** | `(string \| { field: string; dateGranularity?: Enum<'day' \| 'week' \| 'month' \| 'quarter' \| 'year'>; alias?: string })[]` | optional | GROUP BY targets (strings or `{field, dateGranularity?}` objects for date bucketing) |
-| **aggregations** | `{ function: Enum<'count' \| 'sum' \| 'avg' \| 'min' \| 'max' \| 'count_distinct'>; field?: string; alias: string; filter?: any }[]` | optional |  |
-| **having** | `any` | optional | HAVING — filter over the aggregated rows (aggregation aliases + groupBy projections); applied engine-side after aggregation |
-| **timezone** | `string` | optional |  |
-| **search** | `string \| { query: string; fields?: string[]; fuzzy?: boolean; operator?: Enum<'and' \| 'or'>; … }` | optional |  |
-| **searchFields** | `string[]` | optional |  |
-| **filter** | `Record<string, any> \| any` | optional | Data Engine query filter conditions |
-
----
-
-#### Option 8
-
-### Properties
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **method** | `'execute'` | ✅ |  |
-| **command** | `any` | ✅ |  |
-| **options** | `Record<string, any>` | optional |  |
-
----
-
-#### Option 9
-
-### Properties
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **method** | `'vectorFind'` | ✅ |  |
-| **object** | `string` | ✅ |  |
-| **vector** | `number[]` | ✅ |  |
-| **where** | `Record<string, any> \| any` | optional |  |
-| **fields** | `string[]` | optional |  |
-| **limit** | `integer` | optional (default: `5`) |  |
-| **threshold** | `number` | optional |  |
-
----
-
-
 ---
 
 ## DataEngineSort
@@ -839,49 +454,6 @@ Options for DataEngine.update operations
 | **traceId** | `string` | optional |  |
 
 
----
-
-## DataEngineUpdateRequest
-
-### Properties
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **method** | `'update'` | ✅ |  |
-| **object** | `string` | ✅ |  |
-| **data** | `Record<string, any>` | ✅ |  |
-| **id** | `string \| number` | optional | ID for single update, or use where in options |
-| **options** | `{ context?: object; where?: Record<string, any> \| any; multi?: boolean; returning?: boolean; … }` | optional |  |
-
-### Nested Shape: `DataEngineUpdateRequest.options`
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **context** | `{ userId?: string; actor?: string; attributedUserId?: string; email?: string; … }` | optional |  |
-| **where** | `Record<string, any> \| any` | optional |  |
-| **upsert** | `never` | optional | [REMOVED] `update.options.upsert` was removed in @objectstack/spec 17 (ADR-0049) — it was declared and allowlisted but never implemented: no engine or driver path ever read it, so `{ upsert: true }` was accepted and silently dropped and the update stayed a plain update. Delete the key. Express create-if-absent explicitly: a by-id update whose id names no row throws RECORD_NOT_FOUND (the by-id not-found gate) rather than inserting, so read the row first (`findOne`) and call `insert` or `update` on what you find. A first-class upsert, if ever built, must reconcile with that gate by design rather than through this silent flag. |
-| **multi** | `boolean` | optional (default: `false`) |  |
-| **returning** | `boolean` | optional (default: `false`) |  |
-| **filter** | `Record<string, any> \| any` | optional | Data Engine query filter conditions |
-
-
----
-
-## DataEngineVectorFindRequest
-
-### Properties
-
-| Property | Type | Required | Description |
-| :--- | :--- | :--- | :--- |
-| **method** | `'vectorFind'` | ✅ |  |
-| **object** | `string` | ✅ |  |
-| **vector** | `number[]` | ✅ |  |
-| **where** | `Record<string, any> \| any` | optional |  |
-| **fields** | `string[]` | optional |  |
-| **limit** | `integer` | optional (default: `5`) |  |
-| **threshold** | `number` | optional |  |
-
-
 ---
 
 ## DroppedFieldsEvent
diff --git a/content/docs/references/index.mdx b/content/docs/references/index.mdx
index 17a7acbbad1..ad5714aef47 100644
--- a/content/docs/references/index.mdx
+++ b/content/docs/references/index.mdx
@@ -1,7 +1,7 @@
 ---
 title: Protocol reference — every schema by module
 navTitle: Protocol Reference
-description: Every schema published by @objectstack/spec — 1559 schemas across 14 protocol modules
+description: Every schema published by @objectstack/spec — 1549 schemas across 14 protocol modules
 ---
 
 {/* ⚠️  AUTO-GENERATED — DO NOT EDIT. Run build-docs.ts to regenerate. Hand-written docs live in the module folders under content/docs/. */}
@@ -23,7 +23,7 @@ counts are sums of the rows they head. Regenerate with
 | [AI Protocol](/docs/references/ai) | 12 | 68 | Agents, tools, skills, RAG and knowledge sources, model registry, conversations. |
 | [API Protocol](/docs/references/api) | 32 | 440 | REST contracts, endpoints, routing, realtime, batch, discovery. |
 | [Automation Protocol](/docs/references/automation) | 15 | 77 | Flows and their nodes, approvals, ETL pipelines, webhooks, state machines, execution records. |
-| [Data Protocol](/docs/references/data) | 31 | 184 | Objects, fields, queries, filters, datasources and drivers — the ObjectQL layer. |
+| [Data Protocol](/docs/references/data) | 31 | 174 | Objects, fields, queries, filters, datasources and drivers — the ObjectQL layer. |
 | [Identity Protocol](/docs/references/identity) | 5 | 27 | Users and accounts, organizations, positions, SCIM provisioning. |
 | [Integration Protocol](/docs/references/integration) | 1 | 12 | The single connector protocol (ADR-0097) — catalog descriptors and provider-bound instances. |
 | [Kernel Protocol](/docs/references/kernel) | 29 | 151 | Plugin lifecycle and manifests, capabilities and security, metadata loading, service registry. |
@@ -34,7 +34,7 @@ counts are sums of the rows they head. Regenerate with
 | [Studio Protocol](/docs/references/studio) | 3 | 35 | Studio designer metadata — the authoring surfaces for the protocols above. |
 | [System Protocol](/docs/references/system) | 37 | 287 | The runtime environment — logging, jobs, cache, metrics, notifications, i18n and compliance. |
 | [UI Protocol](/docs/references/ui) | 16 | 172 | Apps, pages, views, dashboards, reports, actions and themes — the ObjectUI layer. |
-| **Total** | **202** | **1559** | 14 protocol modules |
+| **Total** | **202** | **1549** | 14 protocol modules |
 
 ---
 
@@ -132,7 +132,7 @@ Flows and their nodes, approvals, ETL pipelines, webhooks, state machines, execu
 
 ## Data Protocol
 
-**Source:** `packages/spec/src/data/` · **Import:** `@objectstack/spec/data` · **31 pages, 184 schemas**
+**Source:** `packages/spec/src/data/` · **Import:** `@objectstack/spec/data` · **31 pages, 174 schemas**
 
 Objects, fields, queries, filters, datasources and drivers — the ObjectQL layer.
 
@@ -141,7 +141,7 @@ Objects, fields, queries, filters, datasources and drivers — the ObjectQL laye
 | [`analytics.zod.ts`](/docs/references/data/analytics) | `AggregationMetricType`, `AnalyticsDateRange`, `AnalyticsDateRangePreset`, `AnalyticsQuery`, `Cube`, `CubeJoin`, `Dimension`, `DimensionType`, `Metric`, `TimeUpdateInterval` |
 | [`column-apply-on.zod.ts`](/docs/references/data/column-apply-on) | `ColumnApplyOn` |
 | [`context-tokens.zod.ts`](/docs/references/data/context-tokens) | `ContextToken`, `ContextTokenPlaceholder` |
-| [`data-engine.zod.ts`](/docs/references/data/data-engine) | `BaseEngineOptions`, `DataEngineAggregateOptions`, `DataEngineAggregateRequest`, `DataEngineCountOptions`, `DataEngineCountRequest`, `DataEngineDeleteOptions`, `DataEngineDeleteRequest`, `DataEngineExecuteRequest`, `DataEngineFilter`, `DataEngineFindOneRequest`, `DataEngineFindRequest`, `DataEngineInsertOptions`, `DataEngineInsertRequest`, `DataEngineQueryOptions`, `DataEngineRequest`, `DataEngineSort`, `DataEngineUpdateOptions`, `DataEngineUpdateRequest`, `DataEngineVectorFindRequest`, `DroppedFieldsEvent`, `EngineAggregateOptions`, `EngineCountOptions`, `EngineDeleteOptions`, `EngineQueryOptions`, `EngineUpdateOptions`, `QueryPageWindow`, `QueryPageWindowParam`, `QueryTransportParams`, `QueryWithTransport`, `ValidationAdvisoryEvent` |
+| [`data-engine.zod.ts`](/docs/references/data/data-engine) | `BaseEngineOptions`, `DataEngineAggregateOptions`, `DataEngineCountOptions`, `DataEngineDeleteOptions`, `DataEngineFilter`, `DataEngineInsertOptions`, `DataEngineQueryOptions`, `DataEngineSort`, `DataEngineUpdateOptions`, `DroppedFieldsEvent`, `EngineAggregateOptions`, `EngineCountOptions`, `EngineDeleteOptions`, `EngineQueryOptions`, `EngineUpdateOptions`, `QueryPageWindow`, `QueryPageWindowParam`, `QueryTransportParams`, `QueryWithTransport`, `ValidationAdvisoryEvent` |
 | [`datasource.zod.ts`](/docs/references/data/datasource) | `Datasource`, `DriverDefinition`, `DriverType`, `ExternalDatasourceSettings`, `SchemaMode` |
 | [`date-macros.zod.ts`](/docs/references/data/date-macros) | `DateMacroPlaceholder`, `DateMacroToken` |
 | [`driver.zod.ts`](/docs/references/data/driver) | `DriverCapabilities`, `DriverConfig`, `DriverOptions`, `PoolConfig` |
diff --git a/docs/adr/0119-plugin-reachable-transactions-and-honest-atomic-batch.md b/docs/adr/0119-plugin-reachable-transactions-and-honest-atomic-batch.md
index bb67ffbae5f..718c46619f8 100644
--- a/docs/adr/0119-plugin-reachable-transactions-and-honest-atomic-batch.md
+++ b/docs/adr/0119-plugin-reachable-transactions-and-honest-atomic-batch.md
@@ -58,7 +58,9 @@ The honest shape is therefore *both*: the transaction is the unit of atomicity f
 
 ### Rot found on the way
 
-**`IDataEngine.batch?`** (`packages/spec/src/contracts/data-engine.ts#IDataEngine`) — the member #4612 opens with. Optional, so nothing must implement it; no engine does. Its entire specification is the three-word comment `Batch Operations (Transactional)` — nothing about partial failure, ordering, cross-object references, rollback scope, or what `transaction: false` means. `DataEngineRequest` is imported by exactly one non-spec file: the contract declaring it. Its request union (`packages/spec/src/data/data-engine.zod.ts#DataEngineRequest`) even nests batches recursively, a shape nobody designed against because nobody built it. The only test (`packages/spec/src/contracts/data-engine.test.ts`) constructs an ad-hoc literal with a `batch` property and asserts it is defined — it pins the type, not an implementation.
+**`IDataEngine.batch?`** (`packages/spec/src/contracts/data-engine.ts#IDataEngine`) — the member #4612 opens with. Optional, so nothing must implement it; no engine does. Its entire specification is the three-word comment `Batch Operations (Transactional)` — nothing about partial failure, ordering, cross-object references, rollback scope, or what `transaction: false` means. `DataEngineRequest` is imported by exactly one non-spec file: the contract declaring it. Its request union (`DataEngineRequest`, in `packages/spec/src/data/data-engine.zod.ts`) even nests batches recursively, a shape nobody designed against because nobody built it. The only test (`packages/spec/src/contracts/data-engine.test.ts`) constructs an ad-hoc literal with a `batch` property and asserts it is defined — it pins the type, not an implementation.
+
+> **Editorial note (2026-10-28, #27028):** `DataEngineRequest` and the rest of that request protocol have since been retired (ADR-0049 enforce-or-remove; registered as `packages/spec/src/migrations/entries/semantic/18.data-engine-rpc-protocol-retired.ts`), so the symbol is named here without an anchor. The finding stands as written: nothing served the union.
 
 **`batchData`'s `atomic` flag** (`packages/metadata-protocol/src/protocol.ts#batchData`) — advertised as *"rollback entire batch on any failure (transaction mode)"*. It opens no transaction. It breaks the loop :
 
diff --git a/docs/audits/2026-07-unknown-key-strictness-ledger.counts/data.md b/docs/audits/2026-07-unknown-key-strictness-ledger.counts/data.md
index 37c7e35c590..6d67334be3f 100644
--- a/docs/audits/2026-07-unknown-key-strictness-ledger.counts/data.md
+++ b/docs/audits/2026-07-unknown-key-strictness-ledger.counts/data.md
@@ -21,7 +21,7 @@ The `strict` column is the one the campaign schedules against; it counts both th
 
 | Dir | Sites | strict | passthrough | catchall | strip |
 |---|---|---|---|---|---|
-| `data/` | 164 | 88 | 2 | 0 | 74 |
+| `data/` | 154 | 88 | 2 | 0 | 64 |
 
 ## `data/` — sites
 
@@ -32,7 +32,7 @@ classify and is not listed (it becomes reportable the day it grows its first sit
 | File | Sites |
 |---|---|
 | `analytics.zod.ts` | 6 |
-| `data-engine.zod.ts` | 16 |
+| `data-engine.zod.ts` | 6 |
 | `datasource.zod.ts` | 6 |
 | `driver-nosql.zod.ts` | 10 |
 | `driver-sql.zod.ts` | 2 |
@@ -57,7 +57,7 @@ classify and is not listed (it becomes reportable the day it grows its first sit
 | `seed-loader.zod.ts` | 12 |
 | `seed.zod.ts` | 2 |
 | `validation.zod.ts` | 6 |
-| **total** | **164** |
+| **total** | **154** |
 
 ## `data/` — open
 
@@ -65,11 +65,11 @@ Per file, how many of its sites still silently discard unknown keys. The `Class`
 column that decides the bucket split is hand-written in the ledger; the arithmetic
 over it is here.
 
-**74 strip of 164**, in 10 file(s).
+**64 strip of 154**, in 10 file(s).
 
 | File | Strip | Sites |
 |---|---|---|
-| `data-engine.zod.ts` | 16 | 16 |
+| `data-engine.zod.ts` | 6 | 6 |
 | `driver-nosql.zod.ts` | 10 | 10 |
 | `driver-sql.zod.ts` | 2 | 2 |
 | `driver.zod.ts` | 9 | 9 |
@@ -79,13 +79,13 @@ over it is here.
 | `hook.zod.ts` | 5 | 8 |
 | `query.zod.ts` | 4 | 5 |
 | `seed-loader.zod.ts` | 12 | 12 |
-| **total** | **74** | **164** |
+| **total** | **64** | **154** |
 
 | Bucket | Sites |
 |---|---|
 | authorable — the ruling's forced scope | 0 |
 | unresolved — needs a per-schema verdict | 0 |
-| wire / open — out of forced scope | 73 |
+| wire / open — out of forced scope | 63 |
 | no door — no carrier, ADR-0049 territory | 1 |
 | no gate — carrier live, no parse | 0 |
 | covered — no carrier, no parse, guarded at every consumer | 0 |
diff --git a/packages/objectql/src/engine.ts b/packages/objectql/src/engine.ts
index 3dcaaed4af7..50a504332d7 100644
--- a/packages/objectql/src/engine.ts
+++ b/packages/objectql/src/engine.ts
@@ -597,8 +597,8 @@ export const HOOK_EVENT_DISPATCH_VOCABULARY = {
  *
  * `where` is the slot every method folds; `limit` additionally applies to the
  * find-shaped bags, which declare `top` (OData) as its alias. The other four
- * pairs in the table are RPC/wire spellings folded at parse by
- * `RpcQueryOptionsSchema` / the protocol normalizer — their values need shape
+ * pairs in the table are wire spellings folded at parse by
+ * `QueryWithTransportSchema` / the protocol normalizer — their values need shape
  * lowering (`sort` records, `populate` lists) that belongs to those layers, so
  * the engine deliberately does not fold them.
  */
diff --git a/packages/spec/DEVELOPMENT_PLAN.md b/packages/spec/DEVELOPMENT_PLAN.md
index b5a2967cb2d..4d9f1cc0d86 100644
--- a/packages/spec/DEVELOPMENT_PLAN.md
+++ b/packages/spec/DEVELOPMENT_PLAN.md
@@ -310,8 +310,8 @@ Replace `id: z.any()` with `z.union([z.string(), z.number()])`:
 
 | File | Fields |
 |---|---|
-| `data/data-engine.zod.ts` L200 | `DataEngineUpdateRequestSchema.id` |
-| `data/data-engine.zod.ts` L207 | `DataEngineDeleteRequestSchema.id` |
+| ~~`data/data-engine.zod.ts` L200~~ | ~~`DataEngineUpdateRequestSchema.id`~~ (retired with the Virtual ObjectQL request protocol, #27028) |
+| ~~`data/data-engine.zod.ts` L207~~ | ~~`DataEngineDeleteRequestSchema.id`~~ (retired with the Virtual ObjectQL request protocol, #27028) |
 
 ### 3.3 Fix critical `z.any()` hotspots (per-file)
 
diff --git a/packages/spec/api-surface/data.json b/packages/spec/api-surface/data.json
index 9031830606f..96b7e6023bd 100644
--- a/packages/spec/api-surface/data.json
+++ b/packages/spec/api-surface/data.json
@@ -169,38 +169,22 @@
     "DRIVER_ID_ALIASES (const)",
     "DataEngineAggregateOptions (type)",
     "DataEngineAggregateOptionsSchema (const)",
-    "DataEngineAggregateRequestSchema (const)",
-    "DataEngineContractSchema (const)",
     "DataEngineCountOptions (type)",
     "DataEngineCountOptionsSchema (const)",
-    "DataEngineCountRequestSchema (const)",
     "DataEngineDeleteOptions (type)",
     "DataEngineDeleteOptionsSchema (const)",
-    "DataEngineDeleteRequestSchema (const)",
-    "DataEngineExecuteRequest (type)",
-    "DataEngineExecuteRequestSchema (const)",
     "DataEngineFilter (type)",
     "DataEngineFilterSchema (const)",
-    "DataEngineFindOneRequestSchema (const)",
-    "DataEngineFindRequestSchema (const)",
     "DataEngineInsertOptions (type)",
     "DataEngineInsertOptionsSchema (const)",
-    "DataEngineInsertRequest (type)",
-    "DataEngineInsertRequestSchema (const)",
     "DataEngineQueryOptions (type)",
     "DataEngineQueryOptionsParsed (type)",
     "DataEngineQueryOptionsSchema (const)",
-    "DataEngineRequest (type)",
-    "DataEngineRequestParsed (type)",
-    "DataEngineRequestSchema (const)",
     "DataEngineSort (type)",
     "DataEngineSortParsed (type)",
     "DataEngineSortSchema (const)",
     "DataEngineUpdateOptions (type)",
     "DataEngineUpdateOptionsSchema (const)",
-    "DataEngineUpdateRequestSchema (const)",
-    "DataEngineVectorFindRequest (type)",
-    "DataEngineVectorFindRequestSchema (const)",
     "DataTypeMapping (type)",
     "DataTypeMappingSchema (const)",
     "Datasource (type)",
diff --git a/packages/spec/authorable-defaults/data.json b/packages/spec/authorable-defaults/data.json
index cbf195cdae1..b15afc4aa00 100644
--- a/packages/spec/authorable-defaults/data.json
+++ b/packages/spec/authorable-defaults/data.json
@@ -16,7 +16,6 @@
     "data/DataEngineInsertOptions:returning = true",
     "data/DataEngineUpdateOptions:multi = false",
     "data/DataEngineUpdateOptions:returning = false",
-    "data/DataEngineVectorFindRequest:limit = 5",
     "data/Datasource:active = true",
     "data/Datasource:autoConnect = false",
     "data/Datasource:origin = \"code\"",
diff --git a/packages/spec/authorable-surface/data.json b/packages/spec/authorable-surface/data.json
index 31a5e674f68..8307e8f4256 100644
--- a/packages/spec/authorable-surface/data.json
+++ b/packages/spec/authorable-surface/data.json
@@ -107,36 +107,13 @@
     "data/DataEngineAggregateOptions:context",
     "data/DataEngineAggregateOptions:filter",
     "data/DataEngineAggregateOptions:groupBy",
-    "data/DataEngineAggregateRequest:method",
-    "data/DataEngineAggregateRequest:object",
-    "data/DataEngineAggregateRequest:query",
     "data/DataEngineCountOptions:context",
     "data/DataEngineCountOptions:filter",
-    "data/DataEngineCountRequest:method",
-    "data/DataEngineCountRequest:object",
-    "data/DataEngineCountRequest:query",
     "data/DataEngineDeleteOptions:context",
     "data/DataEngineDeleteOptions:filter",
     "data/DataEngineDeleteOptions:multi",
-    "data/DataEngineDeleteRequest:id",
-    "data/DataEngineDeleteRequest:method",
-    "data/DataEngineDeleteRequest:object",
-    "data/DataEngineDeleteRequest:options",
-    "data/DataEngineExecuteRequest:command",
-    "data/DataEngineExecuteRequest:method",
-    "data/DataEngineExecuteRequest:options",
-    "data/DataEngineFindOneRequest:method",
-    "data/DataEngineFindOneRequest:object",
-    "data/DataEngineFindOneRequest:query",
-    "data/DataEngineFindRequest:method",
-    "data/DataEngineFindRequest:object",
-    "data/DataEngineFindRequest:query",
     "data/DataEngineInsertOptions:context",
     "data/DataEngineInsertOptions:returning",
-    "data/DataEngineInsertRequest:data",
-    "data/DataEngineInsertRequest:method",
-    "data/DataEngineInsertRequest:object",
-    "data/DataEngineInsertRequest:options",
     "data/DataEngineQueryOptions:context",
     "data/DataEngineQueryOptions:filter",
     "data/DataEngineQueryOptions:limit",
@@ -150,18 +127,6 @@
     "data/DataEngineUpdateOptions:multi",
     "data/DataEngineUpdateOptions:returning",
     "data/DataEngineUpdateOptions:upsert [RETIRED]",
-    "data/DataEngineUpdateRequest:data",
-    "data/DataEngineUpdateRequest:id",
-    "data/DataEngineUpdateRequest:method",
-    "data/DataEngineUpdateRequest:object",
-    "data/DataEngineUpdateRequest:options",
-    "data/DataEngineVectorFindRequest:fields",
-    "data/DataEngineVectorFindRequest:limit",
-    "data/DataEngineVectorFindRequest:method",
-    "data/DataEngineVectorFindRequest:object",
-    "data/DataEngineVectorFindRequest:threshold",
-    "data/DataEngineVectorFindRequest:vector",
-    "data/DataEngineVectorFindRequest:where",
     "data/DataTypeMapping:binary",
     "data/DataTypeMapping:boolean",
     "data/DataTypeMapping:date",
diff --git a/packages/spec/declaration-map/data.json b/packages/spec/declaration-map/data.json
index 790a2205074..42d67397f28 100644
--- a/packages/spec/declaration-map/data.json
+++ b/packages/spec/declaration-map/data.json
@@ -53,34 +53,20 @@
     "CurrencyConfigSchema": "data/CurrencyConfig",
     "DataEngineAggregateOptions": "data/DataEngineAggregateOptions",
     "DataEngineAggregateOptionsSchema": "data/DataEngineAggregateOptions",
-    "DataEngineAggregateRequestSchema": "data/DataEngineAggregateRequest",
     "DataEngineCountOptions": "data/DataEngineCountOptions",
     "DataEngineCountOptionsSchema": "data/DataEngineCountOptions",
-    "DataEngineCountRequestSchema": "data/DataEngineCountRequest",
     "DataEngineDeleteOptions": "data/DataEngineDeleteOptions",
     "DataEngineDeleteOptionsSchema": "data/DataEngineDeleteOptions",
-    "DataEngineDeleteRequestSchema": "data/DataEngineDeleteRequest",
-    "DataEngineExecuteRequest": "data/DataEngineExecuteRequest",
-    "DataEngineExecuteRequestSchema": "data/DataEngineExecuteRequest",
     "DataEngineFilter": "data/DataEngineFilter",
     "DataEngineFilterSchema": "data/DataEngineFilter",
-    "DataEngineFindOneRequestSchema": "data/DataEngineFindOneRequest",
-    "DataEngineFindRequestSchema": "data/DataEngineFindRequest",
     "DataEngineInsertOptions": "data/DataEngineInsertOptions",
     "DataEngineInsertOptionsSchema": "data/DataEngineInsertOptions",
-    "DataEngineInsertRequest": "data/DataEngineInsertRequest",
-    "DataEngineInsertRequestSchema": "data/DataEngineInsertRequest",
     "DataEngineQueryOptions": "data/DataEngineQueryOptions",
     "DataEngineQueryOptionsSchema": "data/DataEngineQueryOptions",
-    "DataEngineRequest": "data/DataEngineRequest",
-    "DataEngineRequestSchema": "data/DataEngineRequest",
     "DataEngineSort": "data/DataEngineSort",
     "DataEngineSortSchema": "data/DataEngineSort",
     "DataEngineUpdateOptions": "data/DataEngineUpdateOptions",
     "DataEngineUpdateOptionsSchema": "data/DataEngineUpdateOptions",
-    "DataEngineUpdateRequestSchema": "data/DataEngineUpdateRequest",
-    "DataEngineVectorFindRequest": "data/DataEngineVectorFindRequest",
-    "DataEngineVectorFindRequestSchema": "data/DataEngineVectorFindRequest",
     "DataTypeMapping": "data/DataTypeMapping",
     "DataTypeMappingSchema": "data/DataTypeMapping",
     "Datasource": "data/Datasource",
diff --git a/packages/spec/docs-import-surface.baseline.json b/packages/spec/docs-import-surface.baseline.json
index 89dd3292fcd..72926d1cef3 100644
--- a/packages/spec/docs-import-surface.baseline.json
+++ b/packages/spec/docs-import-surface.baseline.json
@@ -11,12 +11,6 @@
     "api/MetadataQueryRequest — no type export",
     "automation/FlowVariable — no type export",
     "data/ComparisonOperator — no type export",
-    "data/DataEngineAggregateRequest — no type export",
-    "data/DataEngineCountRequest — no type export",
-    "data/DataEngineDeleteRequest — no type export",
-    "data/DataEngineFindOneRequest — no type export",
-    "data/DataEngineFindRequest — no type export",
-    "data/DataEngineUpdateRequest — no type export",
     "data/DateGranularity — no type export",
     "data/EqualityOperator — no type export",
     "data/HookEvent — no type export",
diff --git a/packages/spec/dropped-refinements.baseline.json b/packages/spec/dropped-refinements.baseline.json
index 8770d6cf062..60d3bd77748 100644
--- a/packages/spec/dropped-refinements.baseline.json
+++ b/packages/spec/dropped-refinements.baseline.json
@@ -2,8 +2,8 @@
   "description": "Shrink-only ledger of every PUBLISHED JSON Schema that is STILL WIDER than the Zod type it was generated from, because a rule written as `.refine()` reaches the runtime and not the file (#18670). `z.toJSONSchema()` has no arm for a `custom` check: a plain record, the same record with a `.refine()`, and the same record with an ABORTING `.refine()` all project byte-identically (measured on zod 4.4.3, the version packages/spec resolves). So a document one of these files ACCEPTS can still be refused at parse time, and an author -- or an AI -- validating against packages/spec/json-schema/** finds out a release later. Each `sites` path is a position under that schema at which a refinement is dropped; the same paths are written onto the artifact itself as `x-dropped-refinements`. Item 2 closed the first patterns: a refinement DECLARED through the closed list in src/shared/refinement-projection.ts is emitted into the published file, reads `projected` rather than `dropped`, and its row LEAVES this ledger in the same PR -- which is why the ledger shrinks and never grows on a repair. Every refinement outside that closed list stays here, and adding an arm to the list is a public-contract decision, not a refactor. Hand-edited on purpose and with no `gen:` script: a generator would let a new gap be admitted by running a command instead of by a decision, which is the silence this ledger exists to end. Adding, removing or moving a site fails packages/spec/scripts/build-schemas.ts until the line moves with it, and the failure prints the corrected entry in full. ⛔ Do not delete or weaken a refinement to shorten this file -- the runtime rule is correct; it is the projection that is silent, and the remedy is to teach the closed list a NAMED pattern, never to drop the rule.",
   "measured": {
     "zod": "4.4.3",
-    "publishedSchemasWithDroppedRefinements": 252,
-    "droppedRefinementSites": 900,
+    "publishedSchemasWithDroppedRefinements": 244,
+    "droppedRefinementSites": 892,
     "refinementSitesThatDidProject": 369,
     "refinementSitesWithNoJsonFormToCompare": 0
   },
@@ -771,71 +771,31 @@
         "filter.options[1].lazy"
       ]
     },
-    "data/DataEngineAggregateRequest": {
-      "sites": [
-        "query.in.having.lazy"
-      ]
-    },
     "data/DataEngineCountOptions": {
       "sites": [
         "filter.options[1].lazy"
       ]
     },
-    "data/DataEngineCountRequest": {
-      "sites": [
-        "query.in.where.options[1].lazy"
-      ]
-    },
     "data/DataEngineDeleteOptions": {
       "sites": [
         "filter.options[1].lazy"
       ]
     },
-    "data/DataEngineDeleteRequest": {
-      "sites": [
-        "options.in.where.options[1].lazy"
-      ]
-    },
     "data/DataEngineFilter": {
       "sites": [
         "options[1].lazy"
       ]
     },
-    "data/DataEngineFindOneRequest": {
-      "sites": [
-        "query.in.where.options[1].lazy"
-      ]
-    },
-    "data/DataEngineFindRequest": {
-      "sites": [
-        "query.in.where.options[1].lazy"
-      ]
-    },
     "data/DataEngineQueryOptions": {
       "sites": [
         "filter.options[1].lazy"
       ]
     },
-    "data/DataEngineRequest": {
-      "sites": [
-        "options[8].where.options[1].lazy"
-      ]
-    },
     "data/DataEngineUpdateOptions": {
       "sites": [
         "filter.options[1].lazy"
       ]
     },
-    "data/DataEngineUpdateRequest": {
-      "sites": [
-        "options.in.where.options[1].lazy"
-      ]
-    },
-    "data/DataEngineVectorFindRequest": {
-      "sites": [
-        "where.options[1].lazy"
-      ]
-    },
     "data/Datasource": {
       "sites": [
         ""
diff --git a/packages/spec/export-origins/data.json b/packages/spec/export-origins/data.json
index c393808c02d..71e26d894d9 100644
--- a/packages/spec/export-origins/data.json
+++ b/packages/spec/export-origins/data.json
@@ -166,38 +166,22 @@
     "DRIVER_ID_ALIASES": "src/data/driver/config-registry.zod.ts#DRIVER_ID_ALIASES (const)",
     "DataEngineAggregateOptions": "src/data/data-engine.zod.ts#DataEngineAggregateOptions (type)",
     "DataEngineAggregateOptionsSchema": "src/data/data-engine.zod.ts#DataEngineAggregateOptionsSchema (const)",
-    "DataEngineAggregateRequestSchema": "src/data/data-engine.zod.ts#DataEngineAggregateRequestSchema (const)",
-    "DataEngineContractSchema": "src/data/data-engine.zod.ts#DataEngineContractSchema (const)",
     "DataEngineCountOptions": "src/data/data-engine.zod.ts#DataEngineCountOptions (type)",
     "DataEngineCountOptionsSchema": "src/data/data-engine.zod.ts#DataEngineCountOptionsSchema (const)",
-    "DataEngineCountRequestSchema": "src/data/data-engine.zod.ts#DataEngineCountRequestSchema (const)",
     "DataEngineDeleteOptions": "src/data/data-engine.zod.ts#DataEngineDeleteOptions (type)",
     "DataEngineDeleteOptionsSchema": "src/data/data-engine.zod.ts#DataEngineDeleteOptionsSchema (const)",
-    "DataEngineDeleteRequestSchema": "src/data/data-engine.zod.ts#DataEngineDeleteRequestSchema (const)",
-    "DataEngineExecuteRequest": "src/data/data-engine.zod.ts#DataEngineExecuteRequest (type)",
-    "DataEngineExecuteRequestSchema": "src/data/data-engine.zod.ts#DataEngineExecuteRequestSchema (const)",
     "DataEngineFilter": "src/data/data-engine.zod.ts#DataEngineFilter (type)",
     "DataEngineFilterSchema": "src/data/data-engine.zod.ts#DataEngineFilterSchema (const)",
-    "DataEngineFindOneRequestSchema": "src/data/data-engine.zod.ts#DataEngineFindOneRequestSchema (const)",
-    "DataEngineFindRequestSchema": "src/data/data-engine.zod.ts#DataEngineFindRequestSchema (const)",
     "DataEngineInsertOptions": "src/data/data-engine.zod.ts#DataEngineInsertOptions (type)",
     "DataEngineInsertOptionsSchema": "src/data/data-engine.zod.ts#DataEngineInsertOptionsSchema (const)",
-    "DataEngineInsertRequest": "src/data/data-engine.zod.ts#DataEngineInsertRequest (type)",
-    "DataEngineInsertRequestSchema": "src/data/data-engine.zod.ts#DataEngineInsertRequestSchema (const)",
     "DataEngineQueryOptions": "src/data/data-engine.zod.ts#DataEngineQueryOptions (type)",
     "DataEngineQueryOptionsParsed": "src/data/data-engine.zod.ts#DataEngineQueryOptionsParsed (type)",
     "DataEngineQueryOptionsSchema": "src/data/data-engine.zod.ts#DataEngineQueryOptionsSchema (const)",
-    "DataEngineRequest": "src/data/data-engine.zod.ts#DataEngineRequest (type)",
-    "DataEngineRequestParsed": "src/data/data-engine.zod.ts#DataEngineRequestParsed (type)",
-    "DataEngineRequestSchema": "src/data/data-engine.zod.ts#DataEngineRequestSchema (const)",
     "DataEngineSort": "src/data/data-engine.zod.ts#DataEngineSort (type)",
     "DataEngineSortParsed": "src/data/data-engine.zod.ts#DataEngineSortParsed (type)",
     "DataEngineSortSchema": "src/data/data-engine.zod.ts#DataEngineSortSchema (const)",
     "DataEngineUpdateOptions": "src/data/data-engine.zod.ts#DataEngineUpdateOptions (type)",
     "DataEngineUpdateOptionsSchema": "src/data/data-engine.zod.ts#DataEngineUpdateOptionsSchema (const)",
-    "DataEngineUpdateRequestSchema": "src/data/data-engine.zod.ts#DataEngineUpdateRequestSchema (const)",
-    "DataEngineVectorFindRequest": "src/data/data-engine.zod.ts#DataEngineVectorFindRequest (type)",
-    "DataEngineVectorFindRequestSchema": "src/data/data-engine.zod.ts#DataEngineVectorFindRequestSchema (const)",
     "DataTypeMapping": "src/data/driver-sql.zod.ts#DataTypeMapping (type)",
     "DataTypeMappingSchema": "src/data/driver-sql.zod.ts#DataTypeMappingSchema (const)",
     "Datasource": "src/data/datasource.zod.ts#Datasource (type)",
diff --git a/packages/spec/json-schema.manifest/data.json b/packages/spec/json-schema.manifest/data.json
index 0ab42398d16..f0da49cd8df 100644
--- a/packages/spec/json-schema.manifest/data.json
+++ b/packages/spec/json-schema.manifest/data.json
@@ -29,23 +29,13 @@
     "data/CubeJoin",
     "data/CurrencyConfig",
     "data/DataEngineAggregateOptions",
-    "data/DataEngineAggregateRequest",
     "data/DataEngineCountOptions",
-    "data/DataEngineCountRequest",
     "data/DataEngineDeleteOptions",
-    "data/DataEngineDeleteRequest",
-    "data/DataEngineExecuteRequest",
     "data/DataEngineFilter",
-    "data/DataEngineFindOneRequest",
-    "data/DataEngineFindRequest",
     "data/DataEngineInsertOptions",
-    "data/DataEngineInsertRequest",
     "data/DataEngineQueryOptions",
-    "data/DataEngineRequest",
     "data/DataEngineSort",
     "data/DataEngineUpdateOptions",
-    "data/DataEngineUpdateRequest",
-    "data/DataEngineVectorFindRequest",
     "data/DataTypeMapping",
     "data/Datasource",
     "data/DateGranularity",
diff --git a/packages/spec/src/contracts/data-engine.ts b/packages/spec/src/contracts/data-engine.ts
index acebfc49fbb..8c3c210504e 100644
--- a/packages/spec/src/contracts/data-engine.ts
+++ b/packages/spec/src/contracts/data-engine.ts
@@ -58,8 +58,8 @@ import type { IntrospectedSchema } from './schema-diff-service.js';
  *
  * Lives on the TS contract — NOT in the serializable Zod options schemas
  * (`EngineUpdateOptionsSchema` etc.): a function is unrepresentable in JSON
- * Schema and cannot cross the RPC (Virtual Data Engine) boundary, so remote
- * callers simply never receive these events. The event payload itself is
+ * Schema and cannot be serialized, so remote callers (REST, the client SDK)
+ * simply never receive these events. The event payload itself is
  * Zod-first: `DroppedFieldsEventSchema` in `data/data-engine.zod.ts`.
  *
  * A listener that throws must never break the write — engines catch and log.
diff --git a/packages/spec/src/data/data-engine-rpc-protocol-retirement.test.ts b/packages/spec/src/data/data-engine-rpc-protocol-retirement.test.ts
new file mode 100644
index 00000000000..6fcad16101e
--- /dev/null
+++ b/packages/spec/src/data/data-engine-rpc-protocol-retirement.test.ts
@@ -0,0 +1,216 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+/**
+ * The Virtual ObjectQL request protocol — `data/data-engine.zod.ts`'s
+ * `DataEngineRequestSchema`, its nine arms and `DataEngineContractSchema` —
+ * RETIRED whole (#27028, ADR-0049 enforce-or-remove), by the maintainer's ruling
+ * A on its decision card (2026-10-28): retire it rather than keep it as a planned
+ * contract. No Virtual Data Engine existed and nothing parsed the protocol.
+ *
+ * Zero readers, measured before the removal (counts plus the tree each was
+ * taken against): objectstack `1287b2fa` — no importer or parser outside
+ * `packages/spec/src/data/` (generated ledgers, reference docs and changelogs
+ * aside; control: 22 files name `DataEngineInsertOptions`, which stays);
+ * hotcrm `353dace`, objectui `b2c0ade` and docs.objectos.ai `cab35fd` — 0
+ * (controls: 311, 2095 and 74 files import `@objectstack/spec`).
+ *
+ * Bookkeeping shapes, pinned below:
+ *   1. No carrier key, so no `retiredKey()` tombstone and no D2 conversion: no
+ *      metadata source authors these shapes, so a conversion would have no seam
+ *      that runs.
+ *   2. `RETIRED_DEFS_BY_MAJOR[18]` carries the ten published defs, and the D3
+ *      entry `data-engine-rpc-protocol-retired` carries the judgement an
+ *      upgrader owes.
+ *   3. The protocol's exports are gone from `@objectstack/spec/data` (and the
+ *      root entry carries none of them), while the option bags `IDataEngine` is
+ *      typed with and `RPC_QUERY_ALIAS_SLOTS` survive (the lit controls).
+ *   4. Tree-scoped absence: nothing inside the declared radius still imports a
+ *      retired export from a spec specifier or reaches one through `Data.`.
+ */
+
+import fs from 'node:fs';
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+
+import { describe, expect, it } from 'vitest';
+
+import * as data from './index';
+import * as root from '../index';
+import { MIGRATIONS_BY_MAJOR, RETIRED_DEFS_BY_MAJOR } from '../migrations/registry';
+
+const ARMS = ['Find', 'FindOne', 'Insert', 'Update', 'Delete', 'Count', 'Aggregate', 'Execute', 'VectorFind'];
+const RETIRED_DEFS = ['data/DataEngineRequest', ...ARMS.map((arm) => `data/DataEngine${arm}Request`)];
+const RETIRED_VALUE_EXPORTS = [
+  'DataEngineRequestSchema',
+  ...ARMS.map((arm) => `DataEngine${arm}RequestSchema`),
+  'DataEngineContractSchema',
+];
+
+describe('the Virtual ObjectQL request protocol is retired whole, and registered', () => {
+  it('RETIRED_DEFS_BY_MAJOR[18] carries the ten published defs', () => {
+    expect(RETIRED_DEFS).toHaveLength(10);
+    for (const def of RETIRED_DEFS) expect(RETIRED_DEFS_BY_MAJOR[18], def).toContain(def);
+  });
+
+  it('the D3 entry `data-engine-rpc-protocol-retired` names the doors that exist', () => {
+    const entry = MIGRATIONS_BY_MAJOR[18]!.semantic.find((s) => s.id === 'data-engine-rpc-protocol-retired');
+    expect(entry).toBeDefined();
+    expect(entry!.replacement).toMatch(/`IDataEngine`/);
+    expect(entry!.replacement).toMatch(/POST \{basePath\}\/batch/);
+    expect(entry!.reason).toMatch(/ADR-0049/);
+    expect(entry!.acceptanceCriteria).toMatch(/TS2305/);
+    // No conversion judged: there is no seam a conversion could run on.
+    expect(entry!.conversionIds).toBeUndefined();
+  });
+});
+
+describe('the protocol\'s exports are gone from every entry that carried them', () => {
+  it.each(RETIRED_VALUE_EXPORTS)('`%s` is exported neither from `@objectstack/spec/data` nor from the root entry', (name) => {
+    expect(Object.keys(data)).not.toContain(name);
+    expect(Object.keys(root)).not.toContain(name);
+  });
+
+  it('the option bags and the alias table survive — the lit controls', () => {
+    for (const name of ['EngineQueryOptionsSchema', 'DataEngineInsertOptionsSchema', 'RPC_QUERY_ALIAS_SLOTS', 'QueryWithTransportSchema']) {
+      expect(Object.keys(data), name).toContain(name);
+    }
+  });
+});
+
+// ─── Tree-scoped absence, with a DECLARED radius ─────────────────────────────
+//
+// `tsc` is the primary sweeper — the protocol's exports are gone, so every
+// typed import fails to compile (TS2305). The residue is what `tsc` never
+// judges: MD/MDX code fences, JSON, YAML and untyped `.js`. This walk covers
+// that residue across the five repo roots `scripts/cross-package-test-inputs.mjs`
+// declares for `@objectstack/spec#test` (mirrored in `turbo.json`), plus the
+// example apps' own `src/` trees, declared there as `examples/*/src/**/*.ts`.
+//
+// Two matchers, each judging a USE, never a mention:
+//   - an `import` / `export … from` naming a retired export from an
+//     `@objectstack/spec` specifier, the type aliases included;
+//   - a `Data.<retired value export>` access through the documented
+//     `import * as Data from '@objectstack/spec/data'` namespace.
+// Inline code is prose and is stripped before judging. The bound, stated:
+// `docs/**`, `.claude/**`, `.github/**` and the repo-root files are outside what
+// this walk sees.
+describe('tree-scoped absence: nothing inside the declared radius still imports the Virtual ObjectQL protocol', () => {
+  const SPEC_ROOT = path.resolve(path.dirname(fileURLToPath(import.meta.url)), '../..');
+  const REPO_ROOT = path.resolve(SPEC_ROOT, '../..');
+  const THIS_FILE = path.relative(REPO_ROOT, fileURLToPath(import.meta.url)).split(path.sep).join('/');
+
+  /** The walked roots — declared in `scripts/cross-package-test-inputs.mjs` under `@objectstack/spec`. */
+  const WALK_ROOTS = ['packages', 'examples', 'skills', 'content', 'scripts'];
+  const SCANNED_EXT = new Set(['.ts', '.mts', '.cts', '.tsx', '.js', '.mjs', '.cjs', '.json', '.md', '.mdx', '.yaml', '.yml']);
+  /** Under `examples/` the non-code extensions, plus `.ts` inside an app's own `src/` tree. */
+  const EXAMPLES_EXT = new Set(['.json', '.md', '.mdx', '.yaml', '.yml']);
+  const EXAMPLE_APP_SRC_TS = /^examples\/[^/]+\/src\/.+\.ts$/;
+  const SKIPPED_DIRS = new Set(['node_modules', 'dist', '.git', '.turbo', '.cache', '.objectstack', 'coverage', '.next', '.source']);
+
+  /** Every retired name: the ten request schemas and their types, and the contract schema. */
+  const RETIRED_NAMES =
+    '(DataEngine(Find|FindOne|Insert|Update|Delete|Count|Aggregate|Execute|VectorFind)?Request(Schema|Parsed)?'
+    + '|DataEngineContractSchema)';
+  const USES = [
+    // An import or re-export naming a retired export from a spec specifier.
+    new RegExp(`\\b(import|export)\\s+(type\\s+)?\\{[^}]*\\b${RETIRED_NAMES}\\b[^}]*\\}\\s*from\\s*['"]@objectstack/spec`, 'm'),
+    // An access through the documented `import * as Data` namespace.
+    new RegExp(`\\bData\\.${RETIRED_NAMES}\\b`, 'm'),
+  ];
+
+  /**
+   * Inline code spans are prose — the house style `check:doc-authoring` enforces
+   * — so stripping single-backtick spans separates "the retirement kit naming
+   * what it removed" from "a source still using it". Newline-bounded: a fenced
+   * block's content is NOT stripped.
+   */
+  const stripInlineCode = (text: string): string => text.replace(/`[^`\n]*`/g, '');
+  const judge = (text: string): RegExpExecArray | null => {
+    const stripped = stripInlineCode(text);
+    for (const re of USES) {
+      const m = re.exec(stripped);
+      if (m) return m;
+    }
+    return null;
+  };
+
+  /**
+   * Structural exclusions — the retirement kit, each with its reason. ⛔ NOT an
+   * allowlist file (`spec-property-retirement` §4).
+   */
+  const EXCLUDED = new Set([
+    // This pin spells the retired names to assert their absence.
+    THIS_FILE,
+  ]);
+  const EXCLUDED_PREFIXES = [
+    // Release-owned prose records the removal; never edited by a code PR.
+    'content/docs/releases/',
+    // GITIGNORED build output (`packages/spec/json-schema/`), reached only
+    // because this is a FILESYSTEM walk. Its source is the Zod tree.
+    'packages/spec/json-schema/',
+  ];
+  /** tsup's own bundle of `tsup.config.ts`, written and deleted mid-build. */
+  const TSUP_BUNDLED_CONFIG = /\.bundled_[^./]+\.mjs$/;
+
+  /** Tolerates ONLY a path that vanished mid-walk; every other read fault is re-raised. */
+  const readIfPresent = (full: string): string | undefined => {
+    try {
+      return fs.readFileSync(full, 'utf-8');
+    } catch (err) {
+      if ((err as NodeJS.ErrnoException)?.code !== 'ENOENT') throw err;
+      return undefined;
+    }
+  };
+
+  it('the matcher recognises a use and ignores a prose mention and the neighbours (anti-vacuity)', () => {
+    // Uses — in each syntax the walk reads.
+    expect(judge("import { DataEngineRequestSchema } from '@objectstack/spec/data';")).not.toBeNull();
+    expect(judge("import type {\n  EngineQueryOptions,\n  DataEngineRequest,\n} from '@objectstack/spec/data';")).not.toBeNull();
+    expect(judge("Prose.\n\n```ts\nimport { DataEngineVectorFindRequestSchema } from '@objectstack/spec';\n```\n")).not.toBeNull();
+    expect(judge("export { DataEngineContractSchema } from '@objectstack/spec/data';")).not.toBeNull();
+    expect(judge('const r = Data.DataEngineFindOneRequestSchema.parse(x);')).not.toBeNull();
+    // Neighbours that must NOT match.
+    expect(judge('the `DataEngineRequestSchema` export was retired')).toBeNull();
+    expect(judge("import { DataEngineInsertOptionsSchema, DataEngineQueryOptions } from '@objectstack/spec/data';")).toBeNull();
+    expect(judge("import { CrossObjectBatchRequestSchema } from '@objectstack/spec/api';")).toBeNull();
+    expect(judge("import { DataEngineRequestSchema } from './local-protocol';")).toBeNull();
+  });
+
+  it('no use of a retired export survives inside the declared radius outside the retirement kit', () => {
+    const offenders: string[] = [];
+    let visited = 0;
+    let exampleSources = 0;
+    const walk = (dir: string) => {
+      for (const entry of fs.readdirSync(dir, { withFileTypes: true })) {
+        const full = path.join(dir, entry.name);
+        const rel = path.relative(REPO_ROOT, full).split(path.sep).join('/');
+        if (entry.isDirectory()) {
+          if (SKIPPED_DIRS.has(entry.name) || entry.name.startsWith('.')) continue;
+          walk(full);
+          continue;
+        }
+        if (!entry.isFile()) continue;
+        const ext = path.extname(entry.name);
+        const scanned = rel.startsWith('examples/')
+          ? EXAMPLES_EXT.has(ext) || EXAMPLE_APP_SRC_TS.test(rel)
+          : SCANNED_EXT.has(ext);
+        if (!scanned) continue;
+        if (entry.name === 'CHANGELOG.md') continue; // release prose records the removal
+        if (EXCLUDED.has(rel) || EXCLUDED_PREFIXES.some((p) => rel.startsWith(p))) continue;
+        if (TSUP_BUNDLED_CONFIG.test(entry.name)) continue;
+        visited += 1;
+        if (EXAMPLE_APP_SRC_TS.test(rel)) exampleSources += 1;
+        const text = readIfPresent(full);
+        if (text === undefined) continue;
+        const m = judge(text);
+        if (m) offenders.push(`${rel} uses \`${m[0].trim().replace(/\s+/g, ' ')}\``);
+      }
+    };
+    for (const root of WALK_ROOTS) walk(path.join(REPO_ROOT, root));
+    // Anti-vacuity: the walk really covered the tree, and the example apps'
+    // sources were really read.
+    expect(visited).toBeGreaterThan(1000);
+    expect(exampleSources).toBeGreaterThan(50);
+    expect(offenders, 'a use of a retired Virtual ObjectQL export means the retirement is being undone').toEqual([]);
+  });
+});
diff --git a/packages/spec/src/data/data-engine.test.ts b/packages/spec/src/data/data-engine.test.ts
index 6ad303fbb6e..acfe0db442a 100644
--- a/packages/spec/src/data/data-engine.test.ts
+++ b/packages/spec/src/data/data-engine.test.ts
@@ -14,16 +14,6 @@ import {
   EngineDeleteOptionsSchema,
   EngineAggregateOptionsSchema,
   EngineCountOptionsSchema,
-  DataEngineFindRequestSchema,
-  DataEngineFindOneRequestSchema,
-  DataEngineInsertRequestSchema,
-  DataEngineUpdateRequestSchema,
-  DataEngineDeleteRequestSchema,
-  DataEngineCountRequestSchema,
-  DataEngineAggregateRequestSchema,
-  DataEngineExecuteRequestSchema,
-  DataEngineVectorFindRequestSchema,
-  DataEngineRequestSchema,
   DroppedFieldsEventSchema,
   QueryTransportParamsSchema,
 } from './data-engine.zod';
@@ -615,436 +605,13 @@ describe('EngineCountOptionsSchema', () => {
   });
 });
 
-describe('DataEngineFindRequestSchema', () => {
-  it('should accept minimal find request', () => {
-    const request = DataEngineFindRequestSchema.parse({
-      method: 'find',
-      object: 'account',
-    });
-
-    expect(request.method).toBe('find');
-    expect(request.object).toBe('account');
-  });
-
-  it('should accept find with query', () => {
-    const request = DataEngineFindRequestSchema.parse({
-      method: 'find',
-      object: 'account',
-      query: {
-        where: { status: 'active' },
-        limit: 10,
-      },
-    });
-
-    expect(request.query?.where).toBeDefined();
-  });
-
-  it('folds legacy params into their canonical keys and drops the aliases', () => {
-    const request = DataEngineFindRequestSchema.parse({
-      method: 'find',
-      object: 'account',
-      query: {
-        filter: { status: 'active' },
-        select: ['id', 'name'],
-        sort: [{ field: 'name', order: 'asc' }],
-        skip: 10,
-        populate: ['owner'],
-        top: 5,
-      },
-    });
-
-    // Legacy input stays accepted (backward compat) — but the parsed output
-    // speaks canonical QueryAST only, so no consumer re-implements precedence.
-    expect(request.query?.where).toEqual({ status: 'active' });
-    expect(request.query?.fields).toEqual(['id', 'name']);
-    expect(request.query?.orderBy).toEqual([{ field: 'name', order: 'asc' }]);
-    expect(request.query?.offset).toBe(10);
-    expect(request.query?.expand).toEqual({ owner: { object: 'owner' } });
-    expect(request.query?.limit).toBe(5);
-    for (const alias of ['filter', 'select', 'sort', 'skip', 'populate', 'top']) {
-      expect(request.query && alias in request.query).toBe(false);
-    }
-  });
-
-  it('lowers the record sort spellings while folding', () => {
-    const named = DataEngineFindRequestSchema.parse({
-      method: 'find',
-      object: 'account',
-      query: { sort: { name: 'desc' } },
-    });
-    expect(named.query?.orderBy).toEqual([{ field: 'name', order: 'desc' }]);
-
-    const numeric = DataEngineFindRequestSchema.parse({
-      method: 'find',
-      object: 'account',
-      query: { sort: { created_at: 1, name: -1 } },
-    });
-    expect(numeric.query?.orderBy).toEqual([
-      { field: 'created_at', order: 'asc' },
-      { field: 'name', order: 'desc' },
-    ]);
-  });
-
-  it('tolerates a redundant identical spelling, refuses a conflicting one', () => {
-    const redundant = DataEngineFindRequestSchema.parse({
-      method: 'find',
-      object: 'account',
-      query: { fields: ['id'], select: ['id'] },
-    });
-    expect(redundant.query?.fields).toEqual(['id']);
-    expect(redundant.query && 'select' in redundant.query).toBe(false);
-
-    const conflict = DataEngineFindRequestSchema.safeParse({
-      method: 'find',
-      object: 'account',
-      query: { fields: ['id'], select: ['name'] },
-    });
-    expect(conflict.success).toBe(false);
-    if (!conflict.success) {
-      expect(conflict.error.issues[0].message).toMatch(/Send exactly one/);
-    }
-  });
-
-  it('refuses a conflicting value on every alias pair', () => {
-    const cases: Array<Record<string, unknown>> = [
-      { filter: { a: 1 }, where: { b: 2 } },
-      { select: ['a'], fields: ['b'] },
-      { sort: [{ field: 'a', order: 'asc' }], orderBy: [{ field: 'b', order: 'asc' }] },
-      { skip: 1, offset: 2 },
-      { populate: ['a'], expand: { b: { object: 'b' } } },
-      { top: 1, limit: 3 },
-    ];
-    for (const query of cases) {
-      const result = DataEngineFindRequestSchema.safeParse({ method: 'find', object: 'account', query });
-      expect(result.success, `${Object.keys(query).join('+')} must be refused`).toBe(false);
-    }
-  });
-});
-
-describe('DataEngineFindOneRequestSchema', () => {
-  it('should accept find one request', () => {
-    const request = DataEngineFindOneRequestSchema.parse({
-      method: 'findOne',
-      object: 'account',
-      query: {
-        where: { id: '123' },
-      },
-    });
-
-    expect(request.method).toBe('findOne');
-  });
-
-  it('folds legacy params into canonical keys (backward compat input)', () => {
-    const request = DataEngineFindOneRequestSchema.parse({
-      method: 'findOne',
-      object: 'account',
-      query: {
-        filter: { id: '123' },
-        select: ['id', 'name'],
-      },
-    });
-
-    expect(request.query?.where).toEqual({ id: '123' });
-    expect(request.query?.fields).toEqual(['id', 'name']);
-    expect(request.query && 'filter' in request.query).toBe(false);
-  });
-});
-
-describe('DataEngineInsertRequestSchema', () => {
-  it('should accept single record insert', () => {
-    const request = DataEngineInsertRequestSchema.parse({
-      method: 'insert',
-      object: 'account',
-      data: { name: 'Test Account' },
-    });
-
-    expect(request.method).toBe('insert');
-    expect(request.data.name).toBe('Test Account');
-  });
-
-  it('should accept multiple records insert', () => {
-    const request = DataEngineInsertRequestSchema.parse({
-      method: 'insert',
-      object: 'account',
-      data: [
-        { name: 'Account 1' },
-        { name: 'Account 2' },
-      ],
-    });
-
-    expect(request.data).toHaveLength(2);
-  });
-
-  it('should accept insert with options', () => {
-    const request = DataEngineInsertRequestSchema.parse({
-      method: 'insert',
-      object: 'account',
-      data: { name: 'Test' },
-      options: {
-        returning: true,
-      },
-    });
-
-    expect(request.options?.returning).toBe(true);
-  });
-});
-
-describe('DataEngineUpdateRequestSchema', () => {
-  it('should accept update with id', () => {
-    const request = DataEngineUpdateRequestSchema.parse({
-      method: 'update',
-      object: 'account',
-      id: '123',
-      data: { status: 'active' },
-    });
-
-    expect(request.id).toBe('123');
-  });
-
-  it('folds a legacy filter into where (backward compat input)', () => {
-    const request = DataEngineUpdateRequestSchema.parse({
-      method: 'update',
-      object: 'account',
-      data: { status: 'active' },
-      options: {
-        filter: { category: 'premium' },
-        multi: true,
-      },
-    });
-
-    expect(request.options?.where).toEqual({ category: 'premium' });
-    expect(request.options && 'filter' in request.options).toBe(false);
-    expect(request.options?.multi).toBe(true);
-  });
-
-  it('should accept update with new where (preferred)', () => {
-    const request = DataEngineUpdateRequestSchema.parse({
-      method: 'update',
-      object: 'account',
-      data: { status: 'active' },
-      options: {
-        where: { category: 'premium' },
-        multi: true,
-      },
-    });
-
-    expect(request.options?.where).toEqual({ category: 'premium' });
-    expect(request.options?.multi).toBe(true);
-  });
-});
-
-describe('DataEngineDeleteRequestSchema', () => {
-  it('should accept delete with id', () => {
-    const request = DataEngineDeleteRequestSchema.parse({
-      method: 'delete',
-      object: 'account',
-      id: '123',
-    });
-
-    expect(request.id).toBe('123');
-  });
-
-  it('folds a legacy filter into where (backward compat input)', () => {
-    const request = DataEngineDeleteRequestSchema.parse({
-      method: 'delete',
-      object: 'account',
-      options: {
-        filter: { status: 'archived' },
-        multi: true,
-      },
-    });
-
-    expect(request.options?.where).toEqual({ status: 'archived' });
-    expect(request.options && 'filter' in request.options).toBe(false);
-    expect(request.options?.multi).toBe(true);
-  });
-
-  it('should accept delete with new where (preferred)', () => {
-    const request = DataEngineDeleteRequestSchema.parse({
-      method: 'delete',
-      object: 'account',
-      options: {
-        where: { status: 'archived' },
-        multi: true,
-      },
-    });
-
-    expect(request.options?.where).toEqual({ status: 'archived' });
-    expect(request.options?.multi).toBe(true);
-  });
-});
-
-describe('DataEngineCountRequestSchema', () => {
-  it('should accept count request', () => {
-    const request = DataEngineCountRequestSchema.parse({
-      method: 'count',
-      object: 'account',
-    });
-
-    expect(request.method).toBe('count');
-  });
-
-  it('should accept count with where (preferred)', () => {
-    const request = DataEngineCountRequestSchema.parse({
-      method: 'count',
-      object: 'account',
-      query: {
-        where: { status: 'active' },
-      },
-    });
-
-    expect(request.query?.where).toBeDefined();
-  });
-
-  it('folds a legacy filter into where (backward compat input)', () => {
-    const request = DataEngineCountRequestSchema.parse({
-      method: 'count',
-      object: 'account',
-      query: {
-        filter: { status: 'active' },
-      },
-    });
-
-    expect(request.query?.where).toEqual({ status: 'active' });
-    expect(request.query && 'filter' in request.query).toBe(false);
-  });
-
-  it('refuses filter + where with different values', () => {
-    const result = DataEngineCountRequestSchema.safeParse({
-      method: 'count',
-      object: 'account',
-      query: { filter: { a: 1 }, where: { b: 2 } },
-    });
-    expect(result.success).toBe(false);
-  });
-});
-
-describe('DataEngineAggregateRequestSchema', () => {
-  it('should accept aggregate request', () => {
-    const request = DataEngineAggregateRequestSchema.parse({
-      method: 'aggregate',
-      object: 'account',
-      query: {
-        groupBy: ['status'],
-        aggregations: [
-          { function: 'sum', field: 'revenue', alias: 'total_revenue' },
-        ],
-      },
-    });
-
-    expect(request.method).toBe('aggregate');
-  });
-});
-
-describe('DataEngineExecuteRequestSchema', () => {
-  it('should accept execute with SQL command', () => {
-    const request = DataEngineExecuteRequestSchema.parse({
-      method: 'execute',
-      command: 'SELECT * FROM accounts WHERE status = ?',
-    });
-
-    expect(request.method).toBe('execute');
-  });
-
-  it('should accept execute with object command', () => {
-    const request = DataEngineExecuteRequestSchema.parse({
-      method: 'execute',
-      command: {
-        operation: 'custom_query',
-        params: { limit: 10 },
-      },
-    });
-
-    expect(request.command.operation).toBe('custom_query');
-  });
-
-  it('should accept execute with options', () => {
-    const request = DataEngineExecuteRequestSchema.parse({
-      method: 'execute',
-      command: 'CUSTOM QUERY',
-      options: {
-        timeout: 5000,
-      },
-    });
-
-    expect(request.options?.timeout).toBe(5000);
-  });
-});
-
-describe('DataEngineVectorFindRequestSchema', () => {
-  it('should accept vector find request', () => {
-    const request = DataEngineVectorFindRequestSchema.parse({
-      method: 'vectorFind',
-      object: 'documents',
-      vector: [0.1, 0.2, 0.3, 0.4],
-    });
-
-    expect(request.method).toBe('vectorFind');
-    expect(request.vector).toHaveLength(4);
-  });
-
-  it('should accept custom limit', () => {
-    const request = DataEngineVectorFindRequestSchema.parse({
-      method: 'vectorFind',
-      object: 'documents',
-      vector: [0.1, 0.2, 0.3],
-      limit: 10,
-    });
-
-    expect(request.limit).toBe(10);
-  });
-
-  it('should accept vector find with filter', () => {
-    const request = DataEngineVectorFindRequestSchema.parse({
-      method: 'vectorFind',
-      object: 'documents',
-      vector: [0.1, 0.2, 0.3],
-      where: { category: 'tech' },
-      limit: 10,
-      threshold: 0.8,
-    });
-
-    expect(request.where).toBeDefined();
-    expect(request.limit).toBe(10);
-    expect(request.threshold).toBe(0.8);
-  });
-
-  it('should accept vector find with fields', () => {
-    const request = DataEngineVectorFindRequestSchema.parse({
-      method: 'vectorFind',
-      object: 'documents',
-      vector: [0.1, 0.2],
-      fields: ['id', 'title', 'content'],
-    });
-
-    expect(request.fields).toHaveLength(3);
-  });
-});
-
 // The `DataEngineBatchRequestSchema` suite that stood here was removed with
-// the schema itself (ADR-0119 D3, #4618). Every case parsed a literal through
-// a schema no production code ever called, so it proved the schema matched
-// itself and nothing more.
-
-describe('DataEngineRequestSchema', () => {
-  it('should accept all request types', () => {
-    const requests = [
-      { method: 'find' as const, object: 'account' },
-      { method: 'findOne' as const, object: 'account' },
-      { method: 'insert' as const, object: 'account', data: {} },
-      { method: 'update' as const, object: 'account', data: {} },
-      { method: 'delete' as const, object: 'account' },
-      { method: 'count' as const, object: 'account' },
-      { method: 'aggregate' as const, object: 'account', query: {} },
-      { method: 'execute' as const, command: 'SQL' },
-      { method: 'vectorFind' as const, object: 'docs', vector: [0.1] },
-    ];
-
-    requests.forEach(request => {
-      expect(() => DataEngineRequestSchema.parse(request)).not.toThrow();
-    });
-  });
-});
+// the schema itself (ADR-0119 D3, #4618), and the suites for the rest of the
+// Virtual ObjectQL request protocol (`DataEngineRequestSchema` and its nine
+// arms) went the same way when #27028 retired it. Every case parsed a literal
+// through a schema no production code ever called, so it proved the schema
+// matched itself and nothing more. The absence pin is
+// `data-engine-rpc-protocol-retirement.test.ts`.
 
 describe('Integration Tests', () => {
   it('should support context in query options', () => {
@@ -1122,79 +689,6 @@ describe('Integration Tests', () => {
     expect(countOpts.context).toBeUndefined();
     expect(aggOpts.context).toBeUndefined();
   });
-
-  it('should support complete CRUD workflow', () => {
-    // Create
-    const insertRequest = DataEngineInsertRequestSchema.parse({
-      method: 'insert',
-      object: 'account',
-      data: { name: 'Test Account', status: 'active' },
-      options: { returning: true },
-    });
-
-    // Read
-    const findRequest = DataEngineFindRequestSchema.parse({
-      method: 'find',
-      object: 'account',
-      query: {
-        where: { status: 'active' },
-        fields: ['id', 'name', 'status'],
-        orderBy: [{ field: 'name', order: 'asc' }],
-        limit: 10,
-      },
-    });
-
-    // Update
-    const updateRequest = DataEngineUpdateRequestSchema.parse({
-      method: 'update',
-      object: 'account',
-      id: '123',
-      data: { status: 'inactive' },
-      options: { returning: true },
-    });
-
-    // Delete
-    const deleteRequest = DataEngineDeleteRequestSchema.parse({
-      method: 'delete',
-      object: 'account',
-      id: '123',
-    });
-
-    expect(insertRequest.method).toBe('insert');
-    expect(findRequest.method).toBe('find');
-    expect(updateRequest.method).toBe('update');
-    expect(deleteRequest.method).toBe('delete');
-  });
-
-  it('should support analytics workflow', () => {
-    // Count
-    const countRequest = DataEngineCountRequestSchema.parse({
-      method: 'count',
-      object: 'opportunity',
-      query: {
-        where: { stage: 'closed_won' },
-      },
-    });
-
-    // Aggregate
-    const aggregateRequest = DataEngineAggregateRequestSchema.parse({
-      method: 'aggregate',
-      object: 'opportunity',
-      query: {
-        where: { status: 'closed' },
-        groupBy: ['stage', 'owner_id'],
-        aggregations: [
-          { function: 'sum', field: 'amount', alias: 'total_amount' },
-          { function: 'avg', field: 'amount', alias: 'avg_amount' },
-          { function: 'count', field: 'id', alias: 'deal_count' },
-        ],
-      },
-    });
-
-    expect(countRequest.method).toBe('count');
-    expect(aggregateRequest.query.aggregations).toHaveLength(3);
-  });
-
 });
 
 describe('DroppedFieldsEventSchema.reason — why a write dropped submitted fields, widened past the readonly pair', () => {
@@ -1246,13 +740,13 @@ describe('DroppedFieldsEventSchema.reason — why a write dropped submitted fiel
 
 describe('the engine-side projection declarations admit exactly what their transport siblings admit', () => {
   /**
-   * [#26954] `EngineQueryOptionsSchema.fields` and the RPC request's
-   * deprecated `select` (`DataEngineFindRequestSchema.query`, and so
-   * `DataEngineFindOneRequestSchema` and the `DataEngineRequestSchema` union)
-   * take the projection's array arm from the one declaration their transport
-   * siblings use: at least one name, none blank. `fields` shares
-   * `FieldNodeSchema` with `$select`; `select` shares `z.string()` with the
-   * bare `select`. So each refusal reads exactly as its sibling's does.
+   * [#26954] `EngineQueryOptionsSchema.fields` and the legacy
+   * `DataEngineQueryOptionsSchema.select` take the projection's array arm from
+   * the one declaration their transport siblings use: at least one name, none
+   * blank. `fields` shares `FieldNodeSchema` with `$select`; `select` shares
+   * `z.string()` with the bare `select`. So each refusal reads exactly as its
+   * sibling's does. (The Virtual ObjectQL request arms' rows left with that
+   * protocol, #27028.)
    */
   const REFUSED: ReadonlyArray<readonly [string, string[], ReadonlyArray<string | number>]> = [
     ['an empty list', [], []],
@@ -1285,35 +779,8 @@ describe('the engine-side projection declarations admit exactly what their trans
     expect(EngineQueryOptionsSchema.parse({ fields: value }).fields).toEqual(value);
   });
 
-  for (const [label, schema, method] of [
-    ['DataEngineFindRequestSchema', DataEngineFindRequestSchema, 'find'],
-    ['DataEngineFindOneRequestSchema', DataEngineFindOneRequestSchema, 'findOne'],
-    ['DataEngineRequestSchema', DataEngineRequestSchema, 'find'],
-  ] as const) {
-    it.each(REFUSED)(`${label}: query.select refuses %s, naming the path, as the bare \`select\` does`, (_name, value, tail) => {
-      const parsed = schema.safeParse({ method, object: 'account', query: { select: value } });
-      expect(parsed.success).toBe(false);
-      const issue = parsed.success ? undefined : parsed.error.issues[0];
-      expect(issue?.path).toEqual(['query', 'select', ...tail]);
-      expect(issue?.message).toBe(sibling('select', value)?.message);
-    });
-
-    it.each(REFUSED)(`${label}: query.fields refuses %s, naming the path`, (_name, value, tail) => {
-      const parsed = schema.safeParse({ method, object: 'account', query: { fields: value } });
-      expect(parsed.success).toBe(false);
-      const issue = parsed.success ? undefined : parsed.error.issues[0];
-      expect(issue?.path).toEqual(['query', 'fields', ...tail]);
-      expect(issue?.message).toBe(sibling('$select', value)?.message);
-    });
-
-    it.each(KEPT)(`${label}: query.select keeps %s, folded onto \`fields\``, (_name, value) => {
-      const parsed = schema.parse({ method, object: 'account', query: { select: value } }) as { query?: Record<string, unknown> };
-      expect(parsed.query).toEqual({ fields: value });
-    });
-  }
-
-  // The legacy options bag's `select` and the vector-find request's `fields`
-  // are `z.string()` lists, so their sibling is the bare `select`.
+  // The legacy options bag's `select` is a `z.string()` list, so its sibling
+  // is the bare `select`.
   it.each(REFUSED)('DataEngineQueryOptionsSchema.select refuses %s, naming the path, as the bare `select` does', (_name, value, tail) => {
     const parsed = DataEngineQueryOptionsSchema.safeParse({ select: value });
     expect(parsed.success).toBe(false);
@@ -1325,22 +792,4 @@ describe('the engine-side projection declarations admit exactly what their trans
   it.each(KEPT)('DataEngineQueryOptionsSchema.select keeps %s, unchanged', (_name, value) => {
     expect(DataEngineQueryOptionsSchema.parse({ select: value }).select).toEqual(value);
   });
-
-  for (const [label, schema] of [
-    ['DataEngineVectorFindRequestSchema', DataEngineVectorFindRequestSchema],
-    ['DataEngineRequestSchema', DataEngineRequestSchema],
-  ] as const) {
-    it.each(REFUSED)(`${label}: vectorFind fields refuses %s, naming the path, as the bare \`select\` does`, (_name, value, tail) => {
-      const parsed = schema.safeParse({ method: 'vectorFind', object: 'doc', vector: [0.1, 0.2], fields: value });
-      expect(parsed.success).toBe(false);
-      const issue = parsed.success ? undefined : parsed.error.issues[0];
-      expect(issue?.path).toEqual(['fields', ...tail]);
-      expect(issue?.message).toBe(sibling('select', value)?.message);
-    });
-
-    it.each(KEPT)(`${label}: vectorFind fields keeps %s, unchanged`, (_name, value) => {
-      const parsed = schema.parse({ method: 'vectorFind', object: 'doc', vector: [0.1, 0.2], fields: value }) as { fields?: string[] };
-      expect(parsed.fields).toEqual(value);
-    });
-  }
 });
diff --git a/packages/spec/src/data/data-engine.zod.ts b/packages/spec/src/data/data-engine.zod.ts
index 81651f409bf..cd3547b66cf 100644
--- a/packages/spec/src/data/data-engine.zod.ts
+++ b/packages/spec/src/data/data-engine.zod.ts
@@ -97,12 +97,10 @@ export const BaseEngineOptionsSchema = lazySchema(() => z.object({
  * rule cannot drift apart.
  *
  * [#26954] The engine-side declarations of the same projection —
- * `EngineQueryOptionsSchema.fields`, `RpcQueryOptionsSchema.select`, the
- * legacy `DataEngineQueryOptionsSchema.select` and
- * `DataEngineVectorFindRequestSchema.fields` — take the array arm from here
- * too. It is declared ahead of both because
- * `RpcQueryOptionsSchema` extends `EngineQueryOptionsSchema` at module load,
- * which runs the lazy factory before any later `const` exists.
+ * `EngineQueryOptionsSchema.fields` and the legacy
+ * `DataEngineQueryOptionsSchema.select` — take the array arm from here too.
+ * (So did the Virtual ObjectQL request arms' `select` / `fields` until #27028
+ * retired that block; see section 9.)
  *
  * [#27166] The array arm and its sentence live in
  * `./projection-names-a-field.ts`, because `QuerySchema.fields` (and so every
@@ -309,8 +307,8 @@ export const EngineUpdateOptionsSchema = lazySchema(() => BaseEngineOptionsSchem
  * Delivered in-process via the `onFieldsDropped` listener on the write options
  * (see `WriteObservabilityOptions` in `contracts/data-engine.ts`). The
  * listener itself is deliberately NOT part of this serializable options
- * schema: a function is unrepresentable in JSON Schema and cannot cross the
- * RPC (Virtual Data Engine) boundary.
+ * schema: a function is unrepresentable in JSON Schema and cannot be
+ * serialized.
  */
 export const DroppedFieldsEventSchema = lazySchema(() => z.object({
   /** Object the write targeted (resolved object name). */
@@ -574,53 +572,21 @@ export const DataEngineCountOptionsSchema = lazySchema(() => BaseEngineOptionsSc
 }).describe('Options for DataEngine.count operations'));
 
 // ==========================================================================
-// 8. Definition (Contract)
+// 8. Definition (Contract) — retired
 // ==========================================================================
-
-export const DataEngineContractSchema = lazySchema(() => z.object({
-  find: z.function()
-    .input(z.tuple([z.string(), EngineQueryOptionsSchema.optional()]))
-    .output(z.promise(z.array(z.unknown()))),
-    
-  findOne: z.function()
-    .input(z.tuple([z.string(), EngineQueryOptionsSchema.optional()]))
-    .output(z.promise(z.unknown())),
-    
-  insert: z.function()
-    .input(z.tuple([z.string(), z.union([z.record(z.string(), z.unknown()), z.array(z.record(z.string(), z.unknown()))]), DataEngineInsertOptionsSchema.optional()]))
-    .output(z.promise(z.unknown())),
-    
-  update: z.function()
-    .input(z.tuple([z.string(), z.record(z.string(), z.unknown()), EngineUpdateOptionsSchema.optional()]))
-    .output(z.promise(z.unknown())),
-    
-  delete: z.function()
-    .input(z.tuple([z.string(), EngineDeleteOptionsSchema.optional()]))
-    .output(z.promise(z.unknown())),
-    
-  count: z.function()
-    .input(z.tuple([z.string(), EngineCountOptionsSchema.optional()]))
-    .output(z.promise(z.number())),
-    
-  aggregate: z.function()
-    .input(z.tuple([z.string(), EngineAggregateOptionsSchema]))
-    .output(z.promise(z.array(z.unknown())))
-}).describe('Standard Data Engine Contract'));
+//
+// `DataEngineContractSchema` stood here until #27028 retired it with the
+// Virtual ObjectQL request protocol (section 9). It restated the engine's
+// methods as `z.function()` members, so no JSON Schema was ever emitted for it,
+// nothing parsed it, and it had drifted from the contract it described: its
+// reads took no trailing options argument and it declared neither `vectorFind`
+// nor `execute`. The contract is `IDataEngine` in `../contracts/data-engine.ts`,
+// a TypeScript interface the compiler holds every engine to.
 
 // ==========================================================================
-// 9. Virtualization & RPC Protocol
+// 9. Query alias slots
 // ==========================================================================
 
-/**
- * Data Engine RPC Request (Virtual ObjectQL)
- * 
- * This schema defines the serialized format for executing Data Engine operations
- * via HTTP, Message Queue, or Plugin boundaries.
- * 
- * It enables "Virtual Data Engines" where the implementation resides in a 
- * separate microservice or plugin.
- */
-
 /**
  * One RPC query-options slot: the canonical QueryAST key plus the deprecated
  * alias spellings that fold into it.
@@ -645,12 +611,12 @@ export interface QueryAliasConflict {
 
 /**
  * The six alias pairs the RPC query surface accepts (#3795, #4346) — the ONE
- * place the alias → canonical mapping is declared. The schema transform below
- * folds parsed input by this table, the protocol normalizer
- * (`metadata-protocol`) folds raw wire input by the same table, extended with
- * the wire-only spellings `filters` / `$filter` / `$expand` that no schema
- * declares, and the ObjectQL engine folds the slots its own option bags still
- * admit (`where`, `limit`) on every entry point. Before this table existed the
+ * place the alias → canonical mapping is declared. The protocol normalizer
+ * (`metadata-protocol`) folds raw wire input by this table, and
+ * {@link QueryWithTransportSchema} folds parsed input by it, both extended with
+ * the transport-only spellings `filters` / `$filter` / `$expand`
+ * ({@link QUERY_TRANSPORT_ALIAS_SLOTS}); the ObjectQL engine folds the slots
+ * its own option bags still admit (`where`, `limit`) on every entry point. Before this table existed the
  * precedence lived in prose only, so every reader re-implemented it — the
  * #3713 condition — and the two readers disagreed on three of the five pairs,
  * four of them backwards.
@@ -724,11 +690,6 @@ export function foldQueryAliasSlots(
   return arrivedAs;
 }
 
-/** The `where` slot alone — for RPC options that accept only the `filter` alias. */
-const RPC_WHERE_SLOT: readonly QueryAliasSlot[] = RPC_QUERY_ALIAS_SLOTS.filter(
-  (slot) => slot.canonical === 'where',
-);
-
 function aliasConflictIssue(conflict: QueryAliasConflict): {
   code: 'custom';
   path: string[];
@@ -744,84 +705,6 @@ function aliasConflictIssue(conflict: QueryAliasConflict): {
   };
 }
 
-/**
- * RPC backward-compatibility mixin — shared `@deprecated filter` field.
- * The parse transform folds `filter` into `where` and drops it; both spellings
- * with different values fail the parse (see `RpcQueryOptionsSchema`).
- */
-const RpcLegacyFilterMixin = {
-  /** @deprecated Use `where` */
-  filter: DataEngineFilterSchema.optional(),
-};
-
-/**
- * Parse-time fold for options that accept only the `filter` alias
- * ({@link RpcLegacyFilterMixin}): `filter` lands on `where` and is dropped
- * from the parsed output, so `filter` is absent from the inferred type and a
- * TS consumer reading it fails to compile instead of silently reading
- * `undefined` (the #3742 / #3764 shape, one layer down).
- */
-function foldRpcLegacyFilter<T extends { filter?: unknown }>(
-  input: T,
-  ctx: z.core.$RefinementCtx,
-): Omit<T, 'filter'> {
-  const bag: Record<string, unknown> = { ...input };
-  foldQueryAliasSlots(bag, RPC_WHERE_SLOT, (conflict) => ctx.addIssue(aliasConflictIssue(conflict)));
-  return bag as Omit<T, 'filter'>;
-}
-
-/**
- * Parse-time fold for the full RPC query options: each legacy alias lands on
- * its canonical key (with the alias's legacy value shape lowered to the
- * canonical one) and is dropped from the parsed output.
- */
-function foldRpcQueryOptions(input: object, ctx: z.core.$RefinementCtx): EngineQueryOptions {
-  const bag = { ...(input as Record<string, unknown>) };
-  foldQueryAliasSlots(bag, RPC_QUERY_ALIAS_SLOTS, (conflict) => ctx.addIssue(aliasConflictIssue(conflict)));
-  // A folded `sort` may carry the record spellings `DataEngineSortSchema`
-  // allows; canonical `orderBy` declares `SortNode[]` only, so lower them.
-  if (bag.orderBy !== undefined && bag.orderBy !== null && !Array.isArray(bag.orderBy)) {
-    bag.orderBy = Object.entries(bag.orderBy as Record<string, 'asc' | 'desc' | 1 | -1>).map(
-      ([field, order]) => ({ field, order: order === 'asc' || order === 1 ? 'asc' : 'desc' }),
-    );
-  }
-  // A folded `populate` is a relation-name list; canonical `expand` is a
-  // `{name: QueryAST}` record.
-  if (Array.isArray(bag.expand)) {
-    bag.expand = Object.fromEntries(
-      (bag.expand as string[]).map((rel) => [rel, { object: rel }]),
-    );
-  }
-  return bag as EngineQueryOptions;
-}
-
-/**
- * RPC query options that accept BOTH new (where/fields/orderBy) and
- * legacy (filter/select/sort/skip/populate) parameter names.
- *
- * **One slot, one value (#3795):** each legacy alias is folded into its
- * canonical key at parse — `filter`→`where`, `select`→`fields`,
- * `sort`→`orderBy`, `skip`→`offset`, `populate`→`expand`, `top`→`limit`
- * ({@link RPC_QUERY_ALIAS_SLOTS}) — and the alias is dropped from the parsed
- * output, so consumers only ever read canonical QueryAST keys. Sending both
- * spellings with the SAME value is redundant and tolerated; sending DIFFERENT
- * values for one slot is irreconcilable — picking either would silently drop
- * the other (#4181) — and fails the parse. The protocol normalizer applies
- * the same table to raw wire input, so mixed vocabularies resolve identically
- * on every path.
- */
-const RpcQueryOptionsSchema = EngineQueryOptionsSchema.extend({
-  ...RpcLegacyFilterMixin,
-  /** @deprecated Use `fields` — the same projection rule (#26954) */
-  select: transportProjectionArray(z.string()).optional(),
-  /** @deprecated Use `orderBy` */
-  sort: DataEngineSortSchema.optional(),
-  /** @deprecated Use `offset` */
-  skip: z.number().int().min(0).optional(),
-  /** @deprecated Use `expand` */
-  populate: z.array(z.string()).optional(),
-}).transform((options, ctx) => foldRpcQueryOptions(options, ctx));
-
 // ==========================================================================
 // 2c. The QUERY TRANSPORT dialect — the FLATTENED SPELLING of the QueryAST
 // ==========================================================================
@@ -1112,9 +995,8 @@ export const QueryTransportParamsSchema = lazySchema(() => z.object({
  * canonical slot via {@link foldQueryAliasSlots}.
  *
  * Deliberately a fold over the shared TABLES rather than a second copy of the
- * normalizer: this is the parse-time application, exactly as
- * `foldRpcQueryOptions` is the parse-time application of
- * {@link RPC_QUERY_ALIAS_SLOTS}.
+ * normalizer: this is the parse-time application of the tables the
+ * normalizer applies at the wire.
  *
  * A CONFLICT — two spellings of one slot carrying different values — fails the
  * parse with {@link aliasConflictIssue} at the canonical path, quoting the
@@ -1451,125 +1333,29 @@ export const QueryWithTransportSchema = lazySchema(
  */
 export type QueryWithTransportParsed = z.infer<typeof QueryWithTransportSchema>;
 
-export const DataEngineFindRequestSchema = lazySchema(() => z.object({
-  method: z.literal('find'),
-  object: z.string(),
-  query: RpcQueryOptionsSchema.optional()
-}));
-
-export const DataEngineFindOneRequestSchema = lazySchema(() => z.object({
-  method: z.literal('findOne'),
-  object: z.string(),
-  query: RpcQueryOptionsSchema.optional()
-}));
-
-export const DataEngineInsertRequestSchema = lazySchema(() => z.object({
-  method: z.literal('insert'),
-  object: z.string(),
-  data: z.union([z.record(z.string(), z.unknown()), z.array(z.record(z.string(), z.unknown()))]),
-  options: DataEngineInsertOptionsSchema.optional()
-}));
-
-export const DataEngineUpdateRequestSchema = lazySchema(() => z.object({
-  method: z.literal('update'),
-  object: z.string(),
-  data: z.record(z.string(), z.unknown()),
-  id: z.union([z.string(), z.number()]).optional().describe('ID for single update, or use where in options'),
-  options: EngineUpdateOptionsSchema.extend(RpcLegacyFilterMixin)
-    .transform((options, ctx) => foldRpcLegacyFilter(options, ctx)).optional()
-}));
-
-export const DataEngineDeleteRequestSchema = lazySchema(() => z.object({
-  method: z.literal('delete'),
-  object: z.string(),
-  id: z.union([z.string(), z.number()]).optional().describe('ID for single delete, or use where in options'),
-  options: EngineDeleteOptionsSchema.extend(RpcLegacyFilterMixin)
-    .transform((options, ctx) => foldRpcLegacyFilter(options, ctx)).optional()
-}));
-
-export const DataEngineCountRequestSchema = lazySchema(() => z.object({
-  method: z.literal('count'),
-  object: z.string(),
-  query: EngineCountOptionsSchema.extend(RpcLegacyFilterMixin)
-    .transform((options, ctx) => foldRpcLegacyFilter(options, ctx)).optional()
-}));
-
-export const DataEngineAggregateRequestSchema = lazySchema(() => z.object({
-  method: z.literal('aggregate'),
-  object: z.string(),
-  query: EngineAggregateOptionsSchema.extend(RpcLegacyFilterMixin)
-    .transform((options, ctx) => foldRpcLegacyFilter(options, ctx))
-}));
-
-/**
- * Data Engine Execute Request (Raw Command)
- * Execute a raw command/query native to the driver (e.g. SQL, Shell, Remote API).
- */
-export const DataEngineExecuteRequestSchema = lazySchema(() => z.object({
-  method: z.literal('execute'),
-  /** The abstract command (string SQL, or JSON object) */
-  command: z.unknown(),
-  /** Optional options */
-  options: z.record(z.string(), z.unknown()).optional()
-}));
-
-/**
- * Data Engine Vector Find Request (AI/RAG)
- * Perform a similarity search using vector embeddings.
- */
-export const DataEngineVectorFindRequestSchema = lazySchema(() => z.object({
-  method: z.literal('vectorFind'),
-  object: z.string(),
-  /** The vector embedding to search for */
-  vector: z.array(z.number()),
-  /** Optional pre-filter (Metadata filtering) — standard QueryAST `where` */
-  where: z.union([z.record(z.string(), z.unknown()), FilterConditionSchema]).optional(),
-  /** Fields to retrieve — standard QueryAST `fields`; the same projection rule (#26954) */
-  fields: transportProjectionArray(z.string()).optional(),
-  /** Number of results */
-  limit: z.number().int().default(5).optional(),
-  /** Minimum similarity score (0-1) or distance threshold */
-  threshold: z.number().optional()
-}));
-
-// `DataEngineBatchRequestSchema` stood here until ADR-0119 D3 (#4618) retired
-// it with the `IDataEngine.batch?` member it existed to describe. Nothing ever
-// parsed it: no engine implemented `batch`, no caller invoked it, and the
-// wire-side batch route validates with `CrossObjectBatchRequestSchema` /
-// `BatchUpdateRequestSchema` from `../api/batch.zod.ts` — a different schema
-// entirely. Deleted outright rather than tombstoned with `retiredKey()`,
-// because a tombstone's prescription reaches an author through a PARSE, and
-// there was no parse to reach: a prescription nobody can receive is noise
-// (the spec-property-retirement playbook's third route). Its three
-// `authorable-surface.json` baseline lines and its `json-schema.manifest.json`
-// entry go with it, deliberately.
+// The Virtual ObjectQL request protocol stood here until #27028 retired it:
+// `DataEngineRequestSchema`, the `method`-discriminated union, and its nine
+// arms (`find`, `findOne`, `insert`, `update`, `delete`, `count`, `aggregate`,
+// `execute`, `vectorFind`), the serialized form of an engine call for a
+// "Virtual Data Engine" living in another process. No such engine existed and
+// nothing parsed the protocol, in this repo or in its sister repos. The one
+// real boundary engine calls cross, the QuickJS hook/action sandbox, speaks
+// `ctx.api.object(name).find(...)` and parses no request schema; the wire batch
+// validates with `CrossObjectBatchRequestSchema` / `BatchUpdateRequestSchema`
+// from `../api/batch.zod.ts`. As published the protocol was also unsafe to
+// implement: every arm admitted a caller-supplied `context` (`isSystem`
+// included), and `execute` carried a raw driver command. Its private helpers
+// (`RpcQueryOptionsSchema` and the `filter`-only fold) went with it;
+// `RPC_QUERY_ALIAS_SLOTS` above stays, since the transport dialect and the
+// engine fold by it.
 //
-// The tell that nobody ever designed against it: its `requests` array nested
-// the request union recursively, so a batch could contain batches, with no
-// statement anywhere about what that meant for ordering or rollback.
-
-/**
- * Unified Data Engine Request Union
- * Use this to validate any incoming "Virtual ObjectQL" request.
- *
- * NOTE (#4618): every arm below now has zero readers in this repo — there is
- * no Virtual Data Engine implementation, only this schema describing one. That
- * makes the whole block an ADR-0049 enforce-or-remove candidate, deliberately
- * left standing here because retiring a published wire protocol is a different
- * decision from retiring `batch?`, and it is tracked separately rather than
- * folded into a removal whose title promised something narrower.
- */
-export const DataEngineRequestSchema = lazySchema(() => z.discriminatedUnion('method', [
-  DataEngineFindRequestSchema,
-  DataEngineFindOneRequestSchema,
-  DataEngineInsertRequestSchema,
-  DataEngineUpdateRequestSchema,
-  DataEngineDeleteRequestSchema,
-  DataEngineCountRequestSchema,
-  DataEngineAggregateRequestSchema,
-  DataEngineExecuteRequestSchema,
-  DataEngineVectorFindRequestSchema
-]).describe('Virtual ObjectQL Request Protocol'));
+// Deleted outright rather than tombstoned with `retiredKey()`, the
+// spec-property-retirement playbook's third route: a tombstone's prescription
+// reaches an author through a PARSE, and there was no parse to reach. The
+// ten JSON Schema defs are registered in `RETIRED_DEFS_BY_MAJOR` and the D3
+// entry `data-engine-rpc-protocol-retired` names the doors that exist.
+// `DataEngineBatchRequestSchema` went the same way earlier (ADR-0119 D3,
+// #4618), together with the `IDataEngine.batch?` member it described.
 
 // ==========================================================================
 // 10. Type Exports
@@ -1634,9 +1420,3 @@ export type DataEngineDeleteOptions = z.input<typeof DataEngineDeleteOptionsSche
 export type DataEngineAggregateOptions = z.input<typeof DataEngineAggregateOptionsSchema>;
 /** @deprecated Use `EngineCountOptions` instead. */
 export type DataEngineCountOptions = z.input<typeof DataEngineCountOptionsSchema>;
-export type DataEngineRequest = z.input<typeof DataEngineRequestSchema>;
-/** Post-parse shape of {@link DataEngineRequest} — defaults applied, transforms run (ADR-0122). */
-export type DataEngineRequestParsed = z.infer<typeof DataEngineRequestSchema>;
-export type DataEngineExecuteRequest = z.input<typeof DataEngineExecuteRequestSchema>;
-export type DataEngineInsertRequest = z.input<typeof DataEngineInsertRequestSchema>;
-export type DataEngineVectorFindRequest = z.input<typeof DataEngineVectorFindRequestSchema>;
diff --git a/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineAggregateRequest.ts b/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineAggregateRequest.ts
new file mode 100644
index 00000000000..795c24de478
--- /dev/null
+++ b/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineAggregateRequest.ts
@@ -0,0 +1,11 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+// #27028 — `data/DataEngineAggregateRequest` — one arm of the `DataEngineRequestSchema` union, the
+// Virtual ObjectQL request protocol (`data/data-engine.zod.ts`) — leaves whole
+// with that protocol under ADR-0049 enforce-or-remove, by the maintainer's
+// ruling A on its decision card (2026-10-28). No Virtual Data Engine existed and
+// nothing parsed the protocol, in this repo or in hotcrm, objectui or
+// docs.objectos.ai. No carrier key, so no `retiredKey()` tombstone and no D2
+// conversion: RETIRED_DEFS_BY_MAJOR plus the D3 semantic entry
+// `data-engine-rpc-protocol-retired` ARE the declaration.
+export const entry = 'data/DataEngineAggregateRequest';
diff --git a/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineCountRequest.ts b/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineCountRequest.ts
new file mode 100644
index 00000000000..a35dae3ae26
--- /dev/null
+++ b/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineCountRequest.ts
@@ -0,0 +1,11 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+// #27028 — `data/DataEngineCountRequest` — one arm of the `DataEngineRequestSchema` union, the
+// Virtual ObjectQL request protocol (`data/data-engine.zod.ts`) — leaves whole
+// with that protocol under ADR-0049 enforce-or-remove, by the maintainer's
+// ruling A on its decision card (2026-10-28). No Virtual Data Engine existed and
+// nothing parsed the protocol, in this repo or in hotcrm, objectui or
+// docs.objectos.ai. No carrier key, so no `retiredKey()` tombstone and no D2
+// conversion: RETIRED_DEFS_BY_MAJOR plus the D3 semantic entry
+// `data-engine-rpc-protocol-retired` ARE the declaration.
+export const entry = 'data/DataEngineCountRequest';
diff --git a/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineDeleteRequest.ts b/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineDeleteRequest.ts
new file mode 100644
index 00000000000..8d1d5143ea3
--- /dev/null
+++ b/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineDeleteRequest.ts
@@ -0,0 +1,11 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+// #27028 — `data/DataEngineDeleteRequest` — one arm of the `DataEngineRequestSchema` union, the
+// Virtual ObjectQL request protocol (`data/data-engine.zod.ts`) — leaves whole
+// with that protocol under ADR-0049 enforce-or-remove, by the maintainer's
+// ruling A on its decision card (2026-10-28). No Virtual Data Engine existed and
+// nothing parsed the protocol, in this repo or in hotcrm, objectui or
+// docs.objectos.ai. No carrier key, so no `retiredKey()` tombstone and no D2
+// conversion: RETIRED_DEFS_BY_MAJOR plus the D3 semantic entry
+// `data-engine-rpc-protocol-retired` ARE the declaration.
+export const entry = 'data/DataEngineDeleteRequest';
diff --git a/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineExecuteRequest.ts b/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineExecuteRequest.ts
new file mode 100644
index 00000000000..5b53f91523e
--- /dev/null
+++ b/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineExecuteRequest.ts
@@ -0,0 +1,11 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+// #27028 — `data/DataEngineExecuteRequest` — one arm of the `DataEngineRequestSchema` union, the
+// Virtual ObjectQL request protocol (`data/data-engine.zod.ts`) — leaves whole
+// with that protocol under ADR-0049 enforce-or-remove, by the maintainer's
+// ruling A on its decision card (2026-10-28). No Virtual Data Engine existed and
+// nothing parsed the protocol, in this repo or in hotcrm, objectui or
+// docs.objectos.ai. No carrier key, so no `retiredKey()` tombstone and no D2
+// conversion: RETIRED_DEFS_BY_MAJOR plus the D3 semantic entry
+// `data-engine-rpc-protocol-retired` ARE the declaration.
+export const entry = 'data/DataEngineExecuteRequest';
diff --git a/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineFindOneRequest.ts b/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineFindOneRequest.ts
new file mode 100644
index 00000000000..ae839ff2196
--- /dev/null
+++ b/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineFindOneRequest.ts
@@ -0,0 +1,11 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+// #27028 — `data/DataEngineFindOneRequest` — one arm of the `DataEngineRequestSchema` union, the
+// Virtual ObjectQL request protocol (`data/data-engine.zod.ts`) — leaves whole
+// with that protocol under ADR-0049 enforce-or-remove, by the maintainer's
+// ruling A on its decision card (2026-10-28). No Virtual Data Engine existed and
+// nothing parsed the protocol, in this repo or in hotcrm, objectui or
+// docs.objectos.ai. No carrier key, so no `retiredKey()` tombstone and no D2
+// conversion: RETIRED_DEFS_BY_MAJOR plus the D3 semantic entry
+// `data-engine-rpc-protocol-retired` ARE the declaration.
+export const entry = 'data/DataEngineFindOneRequest';
diff --git a/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineFindRequest.ts b/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineFindRequest.ts
new file mode 100644
index 00000000000..7eda21c145b
--- /dev/null
+++ b/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineFindRequest.ts
@@ -0,0 +1,11 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+// #27028 — `data/DataEngineFindRequest` — one arm of the `DataEngineRequestSchema` union, the
+// Virtual ObjectQL request protocol (`data/data-engine.zod.ts`) — leaves whole
+// with that protocol under ADR-0049 enforce-or-remove, by the maintainer's
+// ruling A on its decision card (2026-10-28). No Virtual Data Engine existed and
+// nothing parsed the protocol, in this repo or in hotcrm, objectui or
+// docs.objectos.ai. No carrier key, so no `retiredKey()` tombstone and no D2
+// conversion: RETIRED_DEFS_BY_MAJOR plus the D3 semantic entry
+// `data-engine-rpc-protocol-retired` ARE the declaration.
+export const entry = 'data/DataEngineFindRequest';
diff --git a/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineInsertRequest.ts b/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineInsertRequest.ts
new file mode 100644
index 00000000000..67d21f8607e
--- /dev/null
+++ b/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineInsertRequest.ts
@@ -0,0 +1,11 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+// #27028 — `data/DataEngineInsertRequest` — one arm of the `DataEngineRequestSchema` union, the
+// Virtual ObjectQL request protocol (`data/data-engine.zod.ts`) — leaves whole
+// with that protocol under ADR-0049 enforce-or-remove, by the maintainer's
+// ruling A on its decision card (2026-10-28). No Virtual Data Engine existed and
+// nothing parsed the protocol, in this repo or in hotcrm, objectui or
+// docs.objectos.ai. No carrier key, so no `retiredKey()` tombstone and no D2
+// conversion: RETIRED_DEFS_BY_MAJOR plus the D3 semantic entry
+// `data-engine-rpc-protocol-retired` ARE the declaration.
+export const entry = 'data/DataEngineInsertRequest';
diff --git a/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineRequest.ts b/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineRequest.ts
new file mode 100644
index 00000000000..ffa5a4812f5
--- /dev/null
+++ b/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineRequest.ts
@@ -0,0 +1,11 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+// #27028 — `data/DataEngineRequest` — the `method`-discriminated union of the nine request arms, the
+// Virtual ObjectQL request protocol (`data/data-engine.zod.ts`) — leaves whole
+// with that protocol under ADR-0049 enforce-or-remove, by the maintainer's
+// ruling A on its decision card (2026-10-28). No Virtual Data Engine existed and
+// nothing parsed the protocol, in this repo or in hotcrm, objectui or
+// docs.objectos.ai. No carrier key, so no `retiredKey()` tombstone and no D2
+// conversion: RETIRED_DEFS_BY_MAJOR plus the D3 semantic entry
+// `data-engine-rpc-protocol-retired` ARE the declaration.
+export const entry = 'data/DataEngineRequest';
diff --git a/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineUpdateRequest.ts b/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineUpdateRequest.ts
new file mode 100644
index 00000000000..c5aa5efeeaf
--- /dev/null
+++ b/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineUpdateRequest.ts
@@ -0,0 +1,11 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+// #27028 — `data/DataEngineUpdateRequest` — one arm of the `DataEngineRequestSchema` union, the
+// Virtual ObjectQL request protocol (`data/data-engine.zod.ts`) — leaves whole
+// with that protocol under ADR-0049 enforce-or-remove, by the maintainer's
+// ruling A on its decision card (2026-10-28). No Virtual Data Engine existed and
+// nothing parsed the protocol, in this repo or in hotcrm, objectui or
+// docs.objectos.ai. No carrier key, so no `retiredKey()` tombstone and no D2
+// conversion: RETIRED_DEFS_BY_MAJOR plus the D3 semantic entry
+// `data-engine-rpc-protocol-retired` ARE the declaration.
+export const entry = 'data/DataEngineUpdateRequest';
diff --git a/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineVectorFindRequest.ts b/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineVectorFindRequest.ts
new file mode 100644
index 00000000000..e0afeddbde8
--- /dev/null
+++ b/packages/spec/src/migrations/entries/retired-defs/18.data__DataEngineVectorFindRequest.ts
@@ -0,0 +1,11 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+// #27028 — `data/DataEngineVectorFindRequest` — one arm of the `DataEngineRequestSchema` union, the
+// Virtual ObjectQL request protocol (`data/data-engine.zod.ts`) — leaves whole
+// with that protocol under ADR-0049 enforce-or-remove, by the maintainer's
+// ruling A on its decision card (2026-10-28). No Virtual Data Engine existed and
+// nothing parsed the protocol, in this repo or in hotcrm, objectui or
+// docs.objectos.ai. No carrier key, so no `retiredKey()` tombstone and no D2
+// conversion: RETIRED_DEFS_BY_MAJOR plus the D3 semantic entry
+// `data-engine-rpc-protocol-retired` ARE the declaration.
+export const entry = 'data/DataEngineVectorFindRequest';
diff --git a/packages/spec/src/migrations/entries/semantic/18.data-engine-rpc-protocol-retired.ts b/packages/spec/src/migrations/entries/semantic/18.data-engine-rpc-protocol-retired.ts
new file mode 100644
index 00000000000..8e565ff8511
--- /dev/null
+++ b/packages/spec/src/migrations/entries/semantic/18.data-engine-rpc-protocol-retired.ts
@@ -0,0 +1,60 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+import type { SemanticMigration } from '../../types.js';
+
+export const entry: SemanticMigration = {
+  id: 'data-engine-rpc-protocol-retired',
+  // No backticks in `surface` — build-upgrade-guide.ts renders it inside a
+  // code span AND a table cell.
+  surface:
+    'the Virtual ObjectQL request protocol in data/data-engine.zod.ts, retired whole: '
+    + 'DataEngineRequestSchema and its nine arms (DataEngineFindRequestSchema, '
+    + 'DataEngineFindOneRequestSchema, DataEngineInsertRequestSchema, DataEngineUpdateRequestSchema, '
+    + 'DataEngineDeleteRequestSchema, DataEngineCountRequestSchema, DataEngineAggregateRequestSchema, '
+    + 'DataEngineExecuteRequestSchema, DataEngineVectorFindRequestSchema), DataEngineContractSchema, '
+    + 'the types DataEngineRequest, DataEngineRequestParsed, DataEngineExecuteRequest, '
+    + 'DataEngineInsertRequest and DataEngineVectorFindRequest, and the ten published defs '
+    + 'data/DataEngineRequest and data/DataEngine{Find,FindOne,Insert,Update,Delete,Count,Aggregate,'
+    + 'Execute,VectorFind}Request',
+  replacement:
+    'call the engine through the doors that exist. In process, call `IDataEngine` '
+    + '(`@objectstack/spec/contracts`) with the `Engine*OptionsSchema` option bags, which stay; a '
+    + 'hook or action body uses `ctx.api.object(name).find(...)` and its siblings. Over the wire, '
+    + 'use the REST data routes (`/data/:object`, `POST /data/:object/query`) or the metadata '
+    + 'protocol behind them, and `POST {basePath}/batch` (`CrossObjectBatchRequestSchema` / '
+    + '`BatchUpdateRequestSchema`) for a batch. `DataEngineContractSchema` has no replacement '
+    + 'schema: the engine contract is the `IDataEngine` interface, which the compiler holds every '
+    + 'engine to',
+  reason:
+    'ADR-0049 enforce-or-remove, by the maintainer\'s ruling A on the decision card for this '
+    + 'protocol (2026-10-28): retire it rather than keep it as a planned contract. The block '
+    + 'described a serialized engine call for a "Virtual Data Engine" in another process (HTTP, '
+    + 'a message queue or a plugin boundary). No such engine existed and nothing parsed the '
+    + 'protocol: a census on objectstack `1287b2fa` found no importer or parser outside '
+    + '`packages/spec/src/data/` (generated ledgers, reference docs and changelogs aside), and '
+    + 'hotcrm `353dace`, objectui `b2c0ade` and docs.objectos.ai `cab35fd` returned zero hits '
+    + 'against controls of 311, 2095 and 74 files importing `@objectstack/spec`. The one real '
+    + 'boundary engine calls cross, the QuickJS hook and action sandbox, speaks '
+    + '`ctx.api.object(name)` and parses no request schema. As published the protocol was also '
+    + 'unsafe to implement: every arm admitted a caller-supplied `context` (`isSystem` included) '
+    + 'and the `execute` arm carried a raw driver command, so enforcing it would first have '
+    + 'meant narrowing it and building a second data door beside REST, batch, MCP and the '
+    + 'sandbox. `DataEngineContractSchema` restated the engine methods as `z.function()` '
+    + 'members, emitted no JSON Schema, and had drifted from `IDataEngine` (no trailing read '
+    + 'options, no `vectorFind`, no `execute`). Why D3 semantic and not a D2 conversion: no '
+    + 'metadata source authors these shapes, so a conversion has no seam that runs, and with '
+    + 'no parse to reach there is no shape a `retiredKey()` tombstone could sit on (the '
+    + '`data-engine-batch-retired` precedent, ADR-0119 D3). Third-party npm consumers are '
+    + 'UNMEASURED.',
+  acceptanceCriteria:
+    'No code imports DataEngineRequestSchema, any of its nine arm schemas, '
+    + 'DataEngineContractSchema or the types DataEngineRequest, DataEngineRequestParsed, '
+    + 'DataEngineExecuteRequest, DataEngineInsertRequest or DataEngineVectorFindRequest from '
+    + '@objectstack/spec or @objectstack/spec/data: every such import is TS2305 after upgrade. '
+    + 'No tool reads `json-schema/data/DataEngine*Request.json` from the package: the ten defs '
+    + 'are absent from `json-schema.manifest/data.json`, the api-surface / declaration-map / '
+    + 'export-origins shards and the generated reference docs. `IDataEngine`, every '
+    + '`*OptionsSchema`, `RPC_QUERY_ALIAS_SLOTS` and the query-transport schemas are '
+    + 'unaffected. ⚠️ Runtime behaviour is deliberately UNCHANGED and must be verified as such: '
+    + 'nothing ever parsed these shapes, so removing them removes no behaviour.',
+};
diff --git a/packages/spec/src/type-alias-convention.pin.test.ts b/packages/spec/src/type-alias-convention.pin.test.ts
index 3dbec506362..10de7763a9a 100644
--- a/packages/spec/src/type-alias-convention.pin.test.ts
+++ b/packages/spec/src/type-alias-convention.pin.test.ts
@@ -285,7 +285,7 @@ import type * as M194 from './automation/assignment-rule.zod.js';
 import type * as M195 from './security/queue.zod.js';
 
 // ---------------------------------------------------------------------------
-// 798 isomorphic aliases: `z.input` === `z.infer`, so no `XParsed` is declared.
+// 795 isomorphic aliases: `z.input` === `z.infer`, so no `XParsed` is declared.
 //
 // That number is machine-checked, not hand-kept. The runtime companion at the
 // bottom of this file recomputes the pin count from the source and asserts that
@@ -803,12 +803,9 @@ export type Iso_data_dataEngine__BaseEngineOptionsSchema = Assert<Eq< z.input< t
 export type Iso_data_dataEngine__DataEngineAggregateOptionsSchema = Assert<Eq< z.input< typeof M56.DataEngineAggregateOptionsSchema >, z.infer< typeof M56.DataEngineAggregateOptionsSchema > >>;
 export type Iso_data_dataEngine__DataEngineCountOptionsSchema = Assert<Eq< z.input< typeof M56.DataEngineCountOptionsSchema >, z.infer< typeof M56.DataEngineCountOptionsSchema > >>;
 export type Iso_data_dataEngine__DataEngineDeleteOptionsSchema = Assert<Eq< z.input< typeof M56.DataEngineDeleteOptionsSchema >, z.infer< typeof M56.DataEngineDeleteOptionsSchema > >>;
-export type Iso_data_dataEngine__DataEngineExecuteRequestSchema = Assert<Eq< z.input< typeof M56.DataEngineExecuteRequestSchema >, z.infer< typeof M56.DataEngineExecuteRequestSchema > >>;
 export type Iso_data_dataEngine__DataEngineFilterSchema = Assert<Eq< z.input< typeof M56.DataEngineFilterSchema >, z.infer< typeof M56.DataEngineFilterSchema > >>;
 export type Iso_data_dataEngine__DataEngineInsertOptionsSchema = Assert<Eq< z.input< typeof M56.DataEngineInsertOptionsSchema >, z.infer< typeof M56.DataEngineInsertOptionsSchema > >>;
-export type Iso_data_dataEngine__DataEngineInsertRequestSchema = Assert<Eq< z.input< typeof M56.DataEngineInsertRequestSchema >, z.infer< typeof M56.DataEngineInsertRequestSchema > >>;
 export type Iso_data_dataEngine__DataEngineUpdateOptionsSchema = Assert<Eq< z.input< typeof M56.DataEngineUpdateOptionsSchema >, z.infer< typeof M56.DataEngineUpdateOptionsSchema > >>;
-export type Iso_data_dataEngine__DataEngineVectorFindRequestSchema = Assert<Eq< z.input< typeof M56.DataEngineVectorFindRequestSchema >, z.infer< typeof M56.DataEngineVectorFindRequestSchema > >>;
 export type Iso_data_dataEngine__DroppedFieldsEventSchema = Assert<Eq< z.input< typeof M56.DroppedFieldsEventSchema >, z.infer< typeof M56.DroppedFieldsEventSchema > >>;
 export type Iso_data_dataEngine__EngineDeleteOptionsSchema = Assert<Eq< z.input< typeof M56.EngineDeleteOptionsSchema >, z.infer< typeof M56.EngineDeleteOptionsSchema > >>;
 export type Iso_data_dataEngine__EngineUpdateOptionsSchema = Assert<Eq< z.input< typeof M56.EngineUpdateOptionsSchema >, z.infer< typeof M56.EngineUpdateOptionsSchema > >>;
@@ -1732,7 +1729,7 @@ describe('ADR-0122 type-alias convention', () => {
   // this title and the section header above the pin list — are now asserted
   // against the recomputed count below, so neither can go stale without a red
   // test naming it.
-  it('still declares all 798 isomorphic pins', () => {
+  it('still declares all 795 isomorphic pins', () => {
     // The truth of each pin is proved by tsc, not here — an `Assert<Eq<...>>`
     // that stops holding is a compile error with the alias named. What tsc
     // cannot notice is a pin that was DELETED: removing the assertion removes
@@ -2667,7 +2664,12 @@ describe('ADR-0122 type-alias convention', () => {
     // never-consumed `{value, currency}` shape a currency value never had (it
     // is a bare number, ADR-0104 D1), is deleted, and its pin
     // (Iso_data_field__CurrencyValueSchema) goes with it. -1 removed.
-    expect(pins).toHaveLength(798);
+    // 798 -> 795 is #27028: the Virtual ObjectQL request protocol retired whole
+    // (`data/data-engine.zod.ts`), and with it the three isomorphic arms pinned
+    // here (Iso_data_dataEngine__DataEngineExecuteRequestSchema,
+    // Iso_data_dataEngine__DataEngineInsertRequestSchema,
+    // Iso_data_dataEngine__DataEngineVectorFindRequestSchema). -3 removed.
+    expect(pins).toHaveLength(795);
 
     // The count is stated in PROSE twice as well — this case's title and the
     // section header above the pin list — and until commit c6b05c76a nothing read either
diff --git a/packages/spec/src/ui/view-grouping-query.ts b/packages/spec/src/ui/view-grouping-query.ts
index 00137e57606..513d432e9d8 100644
--- a/packages/spec/src/ui/view-grouping-query.ts
+++ b/packages/spec/src/ui/view-grouping-query.ts
@@ -167,9 +167,8 @@
  * (`packages/metadata-protocol/src/protocol.ts`, the `hasGroupBy ||
  * hasAggregations` branch) and answers `{ object, records, total, hasMore }`
  * with the header rows as `records`; `client.data.query()`
- * (`packages/client/src/index.ts`) posts there, and the RPC face declares
- * `method: 'aggregate'` with an `EngineAggregateOptions` body
- * (`data/data-engine.zod.ts`, `DataEngineAggregateRequestSchema`). The row
+ * (`packages/client/src/index.ts`) posts there; in process the same body is
+ * `IDataEngine.aggregate`'s `EngineAggregateOptions`. The row
  * page is the same door with the compiled `EngineQueryOptions`. No new
  * route, no new wire shape; the platform half of the card PINS that door on
  * the compiled queries (the 186-row fixture through the route, on driver-sql
diff --git a/packages/spec/test-typecheck-debt.json b/packages/spec/test-typecheck-debt.json
index 306f5a69174..4b879b91ffb 100644
--- a/packages/spec/test-typecheck-debt.json
+++ b/packages/spec/test-typecheck-debt.json
@@ -95,9 +95,8 @@
       "TS6133: 'key' is declared but its value is never read.": 1
     },
     "src/data/data-engine.test.ts": {
-      "TS18046: 'request.command' is of type 'unknown'.": 1,
       "TS2339: Property 'created_at' does not exist on type '…'.": 2,
-      "TS2339: Property 'name' does not exist on type '…'.": 3
+      "TS2339: Property 'name' does not exist on type '…'.": 2
     },
     "src/data/display-name.test.ts": {
       "TS2339: Property 'fields' does not exist on type '…'.": 1,
diff --git a/packages/spec/unemitted-schemas.baseline.json b/packages/spec/unemitted-schemas.baseline.json
index 8370b39756b..8daff12d1d7 100644
--- a/packages/spec/unemitted-schemas.baseline.json
+++ b/packages/spec/unemitted-schemas.baseline.json
@@ -45,10 +45,6 @@
       "cause": "function",
       "reason": "The union of all four `functions` entry shapes. Its first member IS the bare `z.function()` above, and #16431 (a)'s per-branch projection does drop that member — measured: 1 branch pruned — but the union still does not publish, because the member behind it is FlowFunctionDeclarationSchema, whose required `handler` is itself a live callable. An unprojectable node in a PROPERTY position is not droppable: every document the declaration accepts has that key, so publishing the record without it would describe a shape no runtime value has. Both lowered members are plain JSON and would publish on their own; what this entry now records is a union that cannot be projected while one of its branches requires a callable."
     },
-    "Data.DataEngineContractSchema": {
-      "cause": "function",
-      "reason": "The engine method contract — `find`/`findOne`/`insert`/`update`/`delete` are `z.function()` members. A CODE interface implemented by an engine, never a document anyone authors or transmits, so no reader loses a reference page."
-    },
     "Data.DriverInterfaceSchema": {
       "cause": "function",
       "reason": "The driver method contract (`connect`, `disconnect`, `checkHealth`, `getPoolStats`, `execute` …), all `z.function()`. A code interface implemented by a driver package; nothing is authored against it."
diff --git a/packages/spec/variant-docs.json b/packages/spec/variant-docs.json
index a4e2a7060ea..762210a9ef7 100644
--- a/packages/spec/variant-docs.json
+++ b/packages/spec/variant-docs.json
@@ -127,12 +127,6 @@
       "exempt": "not-authorable",
       "reason": "API response envelope, not authored metadata."
     },
-    {
-      "key": "method:aggregate|count|delete|execute|find|findOne|insert|update|vectorFind",
-      "label": "data-engine request",
-      "exempt": "not-authorable",
-      "reason": "Engine RPC contract. Two entries collapsed into this one when #4618 retired `IDataEngine.batch?`: the outer union carried a `batch` variant, and a second entry described the inner union inside `DataEngineBatchRequestSchema.requests` — this same member set minus `batch`. That inner union is gone with the schema, and the outer one narrowed to exactly this set."
-    },
     {
       "key": "type:delete|insert|retain",
       "label": "collaboration op component",
diff --git a/packages/spec/vitest.repo-tests.json b/packages/spec/vitest.repo-tests.json
index 5a6b43d58b4..c7c443eda16 100644
--- a/packages/spec/vitest.repo-tests.json
+++ b/packages/spec/vitest.repo-tests.json
@@ -43,6 +43,7 @@
   "src/data/cube-refresh-key-retirement.test.ts",
   "src/data/currency-mode-family-closure.pin.test.ts",
   "src/data/currency-value-retirement.test.ts",
+  "src/data/data-engine-rpc-protocol-retirement.test.ts",
   "src/data/document-schemas-retirement.test.ts",
   "src/data/driver/turso-encryption-key-retirement.test.ts",
   "src/data/object-external-sharing-model-retirement.test.ts",