@@ -0,0 +1,21 @@
+---
+'@objectstack/driver-odata': patch
+'@objectstack/spec': patch
+---
+
+feat(driver-odata): a new package, `@objectstack/driver-odata`, serves an OData v4 service's entity sets as external objects through a plugin driver, with no code per entity set
+
+Clause-②: no
+Metadata-protocol: none
+
+A server plugin, `createODataDriverPlugin({ name, serviceRoot, auth, pageSize, requestTimeoutMs, secrets })`, publishes an `ODataDriver` as the kernel service `driver.NAME` (`driver.odata` by default). The datasource it serves is declared as any plugin-driver datasource is (its `name` and `driver` both the plugin's `name`, `schemaMode: 'external'`), and each object binds an entity set through `external.remoteName`, renaming properties through `external.columnMap`.
+
+- **A plugin driver id, not a built-in one.** The id is not added to the spec's driver vocabulary, so the engine floors the driver: what the driver does not narrow, the engine applies in memory under its 1000-row cap. `supports` makes no pushdown claim.
+- **Reads.** `find` sends `$filter`, `$orderby`, `$select`, `$top` and `$skip` and follows `@odata.nextLink` (same origin only). `$filter` carries comparisons, `$in`, `$between`, `$null`, `contains` / `startswith` / `endswith` / case-folded `contains`, under `and` / `or`; anything else (`$not`, `$like`, text ordering and negation, field references, collection properties) is left to the engine, so the service is only ever asked a wider question. A paged read is ordered by the entity key last. `count` sends `$count=true` when the whole `where` was translated and refuses otherwise.
+- **Writes**, under the datasource's `external.allowWrites` and the object's `external.writable`: `POST`, `PATCH` and `DELETE` by key, with `If-Match` carrying the `@odata.etag` of the row's last read. Only properties the entity type declares are sent. A refused write reaches the caller as `422 EXTERNAL_WRITE_REFUSED` with the service's message; `upsert`, the bulk verbs and transactions are refused by name.
+- **Keys and schema.** The key comes from `$metadata` (CSDL 4.0, inheritance and namespace aliases resolved); a row's `id` is the key's value, or the key predicate body for a composite key. `introspectSchema` lists entity sets, EDM-typed properties, keys and single-valued navigation properties as lookup candidates.
+- **Credentials.** The secret is the datasource's `external.credentialsRef`, dereferenced through the host's datasource secret store (`options.secrets`, the same binder the datasource admin plugin takes) at the first request, and again once after a 401. `bearer` and `basic` are supported; a missing reference, store or secret refuses the request rather than sending it unauthenticated. The config itself refuses a `serviceRoot` that carries credentials.
+- **Read scopes.** A `ReadableIds` leaf (a read-scope semi-join) is refused by the driver itself, in the shared refusal envelope, before anything is sent: `$filter` cannot spell it, and leaving it out would read it as no restriction.
+- **Conformance.** The package runs all eleven shared driver case-sets, behind the real engine floor, over an in-process OData service that evaluates the `$filter` the driver writes, under an ordinal and a case-insensitive collation.
+- **`@objectstack/spec`:** `llms.txt` counts the new package (73 published).
+- **The dialect seam.** Headers, the response envelope, the `$metadata` reader, literal and function spellings and the count option go through one `ODataDialect`; only `odataV4Dialect` ships. A v2 dialect is a new file implementing it.
@@ -36,6 +36,7 @@
       "@objectstack/driver-mongodb",
       "@objectstack/driver-sqlite-wasm",
       "@objectstack/driver-turso",
+      "@objectstack/driver-odata",
       "@objectstack/plugin-approvals",
       "@objectstack/plugin-audit",
       "@objectstack/plugin-auth",
 
@@ -0,0 +1,202 @@
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@@ -0,0 +1,84 @@
+# @objectstack/driver-odata
+
+An OData v4 datasource driver for ObjectStack. Declare a datasource over an OData
+service (SAP S/4HANA, Dynamics 365, Dataverse, any CSDL 4.0 service), bind objects to
+its entity sets, and every view, form, permission and hook works on them, live. No row
+is stored on the platform side, and no code is written per entity set.
+
+The driver is a **plugin driver**: a server plugin publishes it as the service
+`driver.<name>`. Its id is not a built-in one, so the engine holds it behind its
+external-driver floor and re-applies every query to the rows the service returns. The
+driver pushes down what it can translate and only ever asks the service a wider
+question; see [Virtual objects](https://objectstack.ai/docs/data-modeling/virtual-objects).
+
+## Usage
+
+```typescript
+import { defineStack } from '@objectstack/spec';
+import { createODataDriverPlugin } from '@objectstack/driver-odata';
+
+export const plugins = [
+  createODataDriverPlugin({
+    name: 'erp',                                   // the datasource it serves
+    serviceRoot: 'https://erp.example.com/odata/v4/sales/',
+    auth: { scheme: 'bearer' },                    // or { scheme: 'basic', username: 'svc_reader' }
+    secrets: datasourceSecretBinder,               // the host's datasource secret store
+  }),
+];
+
+export default defineStack({
+  manifest: { id: 'com.example.sales', name: 'Sales', version: '1.0.0', type: 'app' },
+  datasources: [{
+    name: 'erp',
+    driver: 'erp',
+    schemaMode: 'external',
+    config: {},
+    external: {
+      allowWrites: true,
+      credentialsRef: 'sys_secret:sec_erp',        // the bearer token / basic password
+      validation: { onMismatch: 'warn', checkOnBoot: false },
+    },
+  }],
+  objects: [{
+    name: 'sales_order',
+    label: 'Sales order',
+    datasource: 'erp',
+    sharingModel: 'public_read_write',
+    external: {
+      remoteName: 'SalesOrders',                   // the entity set
+      writable: true,
+      columnMap: { SalesOrderID: 'order_number', CustomerName: 'customer_name', NetAmount: 'net_amount' },
+    },
+    fields: {
+      order_number: { type: 'text', label: 'Order' },
+      customer_name: { type: 'text', label: 'Customer' },
+      net_amount: { type: 'number', label: 'Net amount' },
+    },
+  }],
+});
+```
+
+## Config
+
+| Key | Default | Meaning |
+| :--- | :--- | :--- |
+| `name` | `odata` | The datasource name, the driver name and its `driver.<name>` service suffix. |
+| `serviceRoot` | — | The service root URL (http or https, no credentials, no query). |
+| `version` | `4.0` | The protocol version. Only the v4 dialect ships. |
+| `auth` | `{ scheme: 'none' }` | `none`, `bearer`, or `basic` with a `username`. The secret is the datasource's `external.credentialsRef`. |
+| `pageSize` | `500` | Rows asked for per server page (`Prefer: odata.maxpagesize`). |
+| `requestTimeoutMs` | `30000` | Per-request timeout. |
+
+## What is pushed down
+
+`$filter`: `$eq`, `$ne`, `$gt`, `$gte`, `$lt`, `$lte`, `$between`, `$in`, `$nin`, `$null`,
+`$contains`, `$startsWith`, `$endsWith` and `$icontains` (ASCII comparands), under `$and`
+and `$or`. Text ordering and negation, `$not`, `$like`, `$exists`, field references and
+collection-valued properties are left to the engine. Also `$orderby`, `$select`, `$top`,
+`$skip`, `@odata.nextLink` paging and `$count=true`.
+
+## Writes
+
+`create`, `update` and `delete` by key, with `If-Match` from the row's last read. A
+refusal by the service answers `422 EXTERNAL_WRITE_REFUSED` with its message. `upsert`,
+the bulk verbs and transactions are refused by name.