feat: add Vertex AI support for Gemini, Claude, Grok, and Mistral

.changeset/anthropic-client-injection.md

@@ -0,0 +1,7 @@
+---
+'@tanstack/ai-anthropic': minor
+---
+
+Add `createAnthropicChatWithClient` and `anthropicVertexText` (from
+`@tanstack/ai-anthropic/vertex`) so Claude can run on Vertex AI and other
+Anthropic-compatible transports.

.changeset/vertex-gemini.md

@@ -0,0 +1,7 @@
+---
+'@tanstack/ai-gemini': minor
+'@tanstack/ai-vertex': minor
+---
+
+Add `@tanstack/ai-vertex` for Gemini on Vertex AI, and allow the Gemini
+client to start without an API key when Vertex or Enterprise mode is on.

.changeset/vertex-grok-mistral.md

@@ -0,0 +1,11 @@
+---
+'@tanstack/ai-grok': minor
+'@tanstack/ai-mistral': minor
+'@tanstack/ai-anthropic': minor
+---
+
+Add Vertex AI factories for Grok (`grokVertexText`, `grokVertexSummarize`)
+and Mistral (`mistralVertexText`) on `@tanstack/ai-grok/vertex` and
+`@tanstack/ai-mistral/vertex`. Vertex factories accept only the chat
+models in the Google partner catalog. `anthropicVertexText` now uses
+the same Vertex Claude catalog.

README.md

@@ -210,8 +210,9 @@ Official adapters include:
 | ------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------ |
 | [`@tanstack/ai-openrouter`](https://tanstack.com/ai/latest/docs/adapters/openrouter) | 300+ models through one OpenRouter API, with per-request cost tracking         |
 | [`@tanstack/ai-openai`](https://tanstack.com/ai/latest/docs/adapters/openai)         | OpenAI chat, image, video, speech, transcription, realtime, and provider tools |
-| [`@tanstack/ai-anthropic`](https://tanstack.com/ai/latest/docs/adapters/anthropic)   | Anthropic Claude chat, thinking, tools, and structured outputs                 |
+| [`@tanstack/ai-anthropic`](https://tanstack.com/ai/latest/docs/adapters/anthropic)   | Anthropic Claude chat, thinking, tools, structured outputs, and Vertex Claude  |
 | [`@tanstack/ai-gemini`](https://tanstack.com/ai/latest/docs/adapters/gemini)         | Google Gemini chat, image, speech, and audio generation                        |
+| [`@tanstack/ai-vertex`](https://tanstack.com/ai/latest/docs/adapters/vertex)         | Gemini on Vertex AI with regional endpoints and Google Cloud credentials       |
 | [`@tanstack/ai-ollama`](https://tanstack.com/ai/latest/docs/adapters/ollama)         | Local Ollama models                                                            |
 | [`@tanstack/ai-grok`](https://tanstack.com/ai/latest/docs/adapters/grok)             | xAI Grok chat, images, and realtime                                            |
 | [`@tanstack/ai-groq`](https://tanstack.com/ai/latest/docs/adapters/groq)             | Groq low-latency inference                                                     |

docs/adapters/anthropic.md

@@ -61,7 +61,68 @@ const config: Omit<AnthropicTextConfig, "apiKey"> = {
 
 const adapter = createAnthropicChat("claude-sonnet-4-6", process.env.ANTHROPIC_API_KEY!, config);
 ```
-
+
+## Claude on Vertex
+
+Use `@tanstack/ai-anthropic/vertex` when Claude must run on Vertex AI. That
+is the path for regional endpoints and Google Cloud credentials.
+
+Install the Vertex SDK next to the Anthropic adapter:
+
+```bash
+npm install @tanstack/ai-anthropic @anthropic-ai/vertex-sdk
+```
+
+```typescript
+import { chat } from "@tanstack/ai";
+import { anthropicVertexText } from "@tanstack/ai-anthropic/vertex";
+
+const stream = chat({
+  adapter: anthropicVertexText("claude-sonnet-5", {
+    project: "my-project",
+    location: "europe-west1",
+  }),
+  messages: [{ role: "user", content: "Hello!" }],
+});
+```
+
+`anthropicVertexText` accepts only the Claude models in the Vertex catalog.
+It does not accept Anthropic-only ids such as `claude-opus-5-fast`.
+
+`project` and `location` use the same names as `@tanstack/ai-vertex`, so one
+auth object works for Gemini and Claude.
+
+If you omit `project`, Application Default Credentials can still fill it.
+`location` is required. You can pass it on the factory or set
+`GOOGLE_CLOUD_LOCATION`, `GOOGLE_VERTEX_LOCATION`, or `CLOUD_ML_REGION`.
+
+Gemini on Vertex lives in [`@tanstack/ai-vertex`](./vertex).
+
+## Custom Anthropic client
+
+Use `createAnthropicChatWithClient` when you already have an
+Anthropic-compatible client. The adapter only needs `beta.messages.create`.
+Message mapping, streaming, tools, media, usage, and structured output stay
+on the same TanStack path.
+
+```bash
+npm install @tanstack/ai-anthropic @anthropic-ai/vertex-sdk
+```
+
+```typescript
+import { AnthropicVertex } from "@anthropic-ai/vertex-sdk";
+import { createAnthropicChatWithClient } from "@tanstack/ai-anthropic";
+
+const client = new AnthropicVertex({
+  projectId: "my-project",
+  region: "europe-west1",
+});
+
+const adapter = createAnthropicChatWithClient("claude-sonnet-5", client);
+```
+
+The injected client must implement the Anthropic Beta Messages protocol.
+Endpoint-specific model and feature support stays the caller's job.
 
 ## Example: Chat Completion
 
@@ -257,7 +318,7 @@ ANTHROPIC_API_KEY=sk-ant-...
 
 ## API Reference
 
-Every factory pair follows the same shape: the short factory (`anthropicText`, `anthropicSummarize`) reads `ANTHROPIC_API_KEY` from the environment, while `createAnthropicChat` / `createAnthropicSummarize` take an explicit API key. Both take `model` as the first argument.
+Every factory pair follows the same shape: the short factory (`anthropicText`, `anthropicSummarize`) reads `ANTHROPIC_API_KEY` from the environment, while `createAnthropicChat` / `createAnthropicSummarize` take an explicit API key. Both take `model` as the first argument. For Claude on Vertex, use `anthropicVertexText` from `@tanstack/ai-anthropic/vertex`. For any other custom transport, `createAnthropicChatWithClient` accepts an Anthropic-compatible Messages client.
 
 ### `anthropicText(model, config?)` / `createAnthropicChat(model, apiKey, config?)`
 
@@ -268,6 +329,26 @@ Creates an Anthropic chat adapter.
 - `model` - Claude model id (e.g. `"claude-sonnet-5"`, `"claude-fable-5"`, `"claude-opus-4-8"`)
 - `config?.baseURL` - Custom base URL (optional)
 
+### `anthropicVertexText(model, config?)`
+
+Creates an Anthropic chat adapter on Vertex. Import it from
+`@tanstack/ai-anthropic/vertex`.
+
+**Parameters:**
+
+- `model` - Claude model id
+- `config.project` - GCP project id (optional if ADC can resolve it)
+- `config.location` - Vertex region (or set `GOOGLE_CLOUD_LOCATION`)
+
+### `createAnthropicChatWithClient(model, client)`
+
+Creates an Anthropic chat adapter using an injected client.
+
+**Parameters:**
+
+- `model` - Claude model id
+- `client` - Client exposing `beta.messages.create`
+
 ### `anthropicSummarize(model, config?)` / `createAnthropicSummarize(model, apiKey, config?)`
 
 Creates an Anthropic summarization adapter.

docs/adapters/gemini.md

@@ -24,6 +24,8 @@ For a full working example with image generation, see the [media generation exam
 npm install @tanstack/ai-gemini
 ```
 
+Need Gemini on Vertex AI (regional endpoints and Google Cloud credentials)? Use the [Vertex adapter](./vertex).
+
 ## Basic Usage
 
 ```typescript

docs/adapters/grok.md

@@ -61,6 +61,50 @@ const config: Omit<GrokTextConfig, "apiKey"> = {
 const adapter = createGrokText("grok-build-0.1", process.env.XAI_API_KEY!, config);
 ```
 
+## Grok on Vertex
+
+Use `@tanstack/ai-grok/vertex` when Grok must run on Vertex AI. That path
+uses Google Cloud credentials and Vertex regional or global endpoints.
+
+```bash
+npm install @tanstack/ai-grok google-auth-library
+```
+
+```typescript
+import { chat } from "@tanstack/ai";
+import { grokVertexText } from "@tanstack/ai-grok/vertex";
+
+const stream = chat({
+  adapter: grokVertexText("grok-4.3", {
+    project: "my-project",
+    location: "global",
+  }),
+  messages: [{ role: "user", content: "Hello!" }],
+});
+```
+
+`project` and `location` use the same names as `@tanstack/ai-vertex`. If you
+omit `location`, the factory uses `global`.
+
+`grokVertexText` accepts only the Grok chat models that Vertex lists:
+
+- `grok-4.3`
+- `grok-4.20-reasoning`
+- `grok-4.20-non-reasoning`
+- `grok-4.1-fast-reasoning`
+- `grok-4.1-fast-non-reasoning`
+
+xAI API models such as `grok-4.6` and `grok-build-0.1` are not on Vertex.
+
+The adapter sends the Vertex model id `xai/grok-4.3`. Install
+`google-auth-library` for Application Default Credentials, or pass
+`authClient` or `getAccessToken`.
+
+Use `grokVertexSummarize` from the same entry when you need summarize on
+Vertex.
+
+Gemini on Vertex lives in [`@tanstack/ai-vertex`](./vertex).
+
 ## Example: Chat Completion
 
 ```typescript

docs/adapters/mistral.md

@@ -73,6 +73,48 @@ const adapter = createMistralText(
 );
 ```
 
+## Mistral on Vertex
+
+Use `@tanstack/ai-mistral/vertex` when Mistral must run on Vertex AI. That
+path uses Google Cloud credentials and the publisher `rawPredict` endpoint.
+
+Mistral on Vertex is regional only. Use `us-central1` or `europe-west4`.
+
+```bash
+npm install @tanstack/ai-mistral google-auth-library
+```
+
+```typescript
+import { chat } from "@tanstack/ai";
+import { mistralVertexText } from "@tanstack/ai-mistral/vertex";
+
+const stream = chat({
+  adapter: mistralVertexText("mistral-medium-3", {
+    project: "my-project",
+    location: "europe-west4",
+  }),
+  messages: [{ role: "user", content: "Hello!" }],
+});
+```
+
+`project` and `location` use the same names as `@tanstack/ai-vertex`.
+`location` is required.
+
+`mistralVertexText` accepts only the Mistral chat models that Vertex lists:
+
+- `mistral-medium-3`
+- `mistral-small-2503`
+- `codestral-2`
+
+Mistral API aliases such as `mistral-large-latest` and `mistral-medium-latest`
+are not Vertex model ids. Vertex also lists `mistral-ocr-2505`, but that
+model is OCR, not chat.
+
+Install `google-auth-library` for Application Default Credentials, or pass
+`authClient` or `getAccessToken`.
+
+Gemini on Vertex lives in [`@tanstack/ai-vertex`](./vertex).
+
 ## Example: Chat Completion
 
 ```typescript