Support for Google Vertex AI (and Vertex-hosted models like Claude Sonnet)

[yamitzky]

Hi, is there any plan to provide an official adapter for Google Vertex AI (including models served via Vertex, such as Anthropic models)?

I couldn’t find any existing discussion or implementation. For reference, the Vercel AI SDK already supports Google Vertex AI: see their documentation at https://ai-sdk.dev/providers/ai-sdk-providers/google-vertex

[da5idb]

The only thing currently preventing this is that the GeminiClientConfig requires an apiKey:

export interface GeminiClientConfig extends GoogleGenAIOptions {
  apiKey: string
}

The config should support using vertex AI as per the google/genai docs:
https://github.com/googleapis/js-genai?tab=readme-ov-file#vertex-ai

import { GoogleGenAI } from '@google/genai';

const ai = new GoogleGenAI({
    vertexai: true,
    project: 'your_project',
    location: 'your_location',
});

[luap2703]

See #136

[sedghi]

Interested

[medihack]

Why this matters beyond convenience: EU data residency

Adding to the original request with a compliance angle that I think strengthens the case.

The Gemini Developer API (AI Studio keys) has no regional endpoints. Even on the paid tier, where Google acts as a processor and doesn't train on prompts, the terms allow data to be cached or stored in any country where Google or its agents operate. There is no way to pin inference to the EU.

Vertex AI (since Cloud Next '26 rebranded to Gemini Enterprise Agent Platform) is the only Gemini surface that offers regional endpoints (europe-west1, europe-west4, EU multi-region) plus ML processing commitments, CMEK, VPC-SC and Cloud audit logging. For EU teams handling personal or regulated data that is often the difference between shipping and not shipping.

As @da5idb noted above, the blocker is small: GeminiClientConfig requires apiKey, while the Vertex path needs { vertexai: true, project, location } and ADC / service-account credentials, which @google/genai already supports natively. Widening the config type (and threading credentials through) would unlock it without a separate adapter.

Related prior art: #989 adds client injection to the Anthropic adapter, which covers Vertex-hosted Claude. The same pattern applied to the Gemini adapter would close this out.

[AlemTuzlak]

Cc @tombeckenham the people have spoken 🤭