diff --git a/docs/openapi.yaml b/docs/openapi.yaml
index 123db6af67..f4cfd804ca 100644
--- a/docs/openapi.yaml
+++ b/docs/openapi.yaml
@@ -6844,7 +6844,8 @@ paths:
         and response shape). Accepts a JSON body referencing a document/image
         and returns extracted text. `model` selects the provider via a
         `provider/model` prefix (e.g. `mistral/mistral-ocr-latest`,
-        `azure-document-intelligence/prebuilt-read`); a bare model id (e.g.
+        `azure-document-intelligence/prebuilt-read`,
+        `vertex-deepseek-ocr/deepseek-ocr-maas`); a bare model id (e.g.
         `mistral-ocr-latest`) resolves to its registered provider, and an
         omitted `model` defaults to Mistral. Azure Document Intelligence is
         asynchronous upstream — the handler polls the returned operation
@@ -6865,7 +6866,8 @@ paths:
                   description: >-
                     `provider/model` id or bare model id. Registered ids:
                     `mistral/mistral-ocr-latest`,
-                    `azure-document-intelligence/prebuilt-read`. Defaults to
+                    `azure-document-intelligence/prebuilt-read`,
+                    `vertex-deepseek-ocr/deepseek-ocr-maas`. Defaults to
                     `mistral-ocr-latest` when omitted.
                 document:
                   type: object
diff --git a/docs/reference/API_REFERENCE.md b/docs/reference/API_REFERENCE.md
index f1d4fce2e9..9ccca26093 100644
--- a/docs/reference/API_REFERENCE.md
+++ b/docs/reference/API_REFERENCE.md
@@ -220,12 +220,13 @@ Content-Type: application/json
 `mistral-ocr-latest`) resolves to its registered provider, and an omitted `model` defaults to
 Mistral (`mistral-ocr-latest`). Registered providers (`open-sse/config/ocrRegistry.ts`):
 
-| Provider id                   | Model id             | `model` value                                               | Notes                                                                          |
-| ----------------------------- | -------------------- | ----------------------------------------------------------- | ------------------------------------------------------------------------------ |
-| `mistral`                     | `mistral-ocr-latest` | `mistral/mistral-ocr-latest` (or bare `mistral-ocr-latest`) | Synchronous — the response is returned directly from the single upstream call. |
-| `azure-document-intelligence` | `prebuilt-read`      | `azure-document-intelligence/prebuilt-read`                 | Asynchronous upstream (`analyze` + poll) — see below.                          |
+| Provider id                   | Model id             | `model` value                                               | Notes                                                                                              |
+| ----------------------------- | -------------------- | ----------------------------------------------------------- | -------------------------------------------------------------------------------------------------- |
+| `mistral`                     | `mistral-ocr-latest` | `mistral/mistral-ocr-latest` (or bare `mistral-ocr-latest`) | Synchronous — the response is returned directly from the single upstream call.                     |
+| `azure-document-intelligence` | `prebuilt-read`      | `azure-document-intelligence/prebuilt-read`                 | Asynchronous upstream (`analyze` + poll) — see below.                                              |
+| `vertex-deepseek-ocr`         | `deepseek-ocr-maas`  | `vertex-deepseek-ocr/deepseek-ocr-maas`                     | Synchronous, via Vertex AI's `openapi/chat/completions` partner endpoint — see below for auth/URL. |
 
-Both providers respond in the same Mistral-shaped body:
+All three providers respond in the same Mistral-shaped body:
 
 ```json
 {
@@ -245,6 +246,19 @@ operation is still running after the attempt budget is exhausted. The final Azur
 normalized into the same `pages`/`markdown` shape used by Mistral before being returned to the
 caller, so client code does not need to special-case the provider.
 
+### Vertex AI DeepSeek OCR auth and endpoint resolution
+
+`vertex-deepseek-ocr` reuses the same Vertex AI authentication OmniRoute already supports for
+chat/image traffic (`open-sse/executors/vertex.ts`): the connection's API key is either a
+Service Account JSON credential (exchanged for a short-lived OAuth access token via the JWT-bearer
+flow) or an already-minted OAuth access token used as-is. The upstream endpoint URL is Vertex's
+generic `openapi/chat/completions` partner endpoint, built from the connection's project and
+region — an explicit `providerSpecificData.project`/`providerSpecificData.region` always wins;
+otherwise the project is derived from the Service Account JSON's `project_id` and the region
+defaults to `us-central1`. Both resolutions happen in `open-sse/handlers/ocr.ts`
+(`resolveVertexOcrAccessToken`, `resolveVertexOcrBaseUrl`), consumed by
+`src/app/api/v1/ocr/route.ts` before dispatching to `handleOcr`.
+
 ---
 
 ## List Models