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Fetch the complete documentation index at: https://braintrust.dev/docs/llms.txt

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Braintrust integrates with Google Cloud Vertex AI, so you can use models from Google and Vertex Model Garden partners through the Braintrust playground, API, and SDKs.

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Confirm model access in Google Cloud

Before configuring Braintrust, make sure your Google Cloud project can call the Vertex AI models you want to use.
  1. Enable the Vertex AI API in your Google Cloud project.
  2. Confirm the model is available in the Vertex location you want to use. See Generative AI locations.
  3. If you use a service account, grant it permissions to invoke Vertex AI models, such as the AI Platform Developer role.
  4. Check your project’s Vertex AI quotas for the model and location you plan to use.

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Configure the integration

  1. Go to Settings > Project AI providers.
  2. Under Cloud providers, click Google Vertex AI.
  3. Choose your authentication method:
    • Access token: Paste a Vertex AI OAuth access token.
    • Service account key: Paste the full service account key JSON. Braintrust exchanges it for an OAuth bearer token when sending requests to Vertex AI.
    API keys are stored as one-way cryptographic hashes, never in plaintext.
  4. Set Project to the Google Cloud project ID where Vertex AI is enabled.
  5. Optional: Set Location to the Vertex location where Braintrust should send requests. If you leave this blank, Braintrust uses global. Some built-in model definitions include their own supported locations, and Braintrust may use those model-specific locations before the provider-level location.
    The global endpoint can improve availability and reduce 429 errors, but Google may route requests to any supported region. If you need to route LLM requests to a specific region, choose a Vertex location.
  6. Optional: Set API base URL only if you need a custom Vertex endpoint. By default, Braintrust uses https://aiplatform.googleapis.com/ for global and https://{location}-aiplatform.googleapis.com/ for regional locations.
  7. Many Vertex AI models are available in Braintrust by default. To access these, leave Include the default registry of Vertex AI models enabled. If the model you want is not supported by default, you can add the model manually.
  8. Click Save.

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Add models manually

You only need to add a Vertex AI model manually if it does not appear in Braintrust’s supported models list. This is common for newly released models, preview models, partner models, or models your Google Cloud project has special access to. When you add a model manually:
  1. Copy the exact Vertex model ID from Google Cloud.
  2. Add it under Models in the Vertex AI provider settings.
  3. Choose the matching Braintrust format.
  4. If the model is only available in specific regions, add those regions under Locations.
Common model ID patterns:
  • publishers/google/models/gemini-2.5-flash - Google Gemini model through Vertex AI.
  • publishers/anthropic/models/claude-haiku-4-5 - Anthropic Claude model through Vertex AI.
  • publishers/meta/models/llama-3.3-70b-instruct-maas - Meta model served through Vertex AI Model Garden.
Prefer the full publisher model ID from Vertex AI when adding models manually. Short Google model IDs can work for Gemini models, but full IDs are clearer and avoid ambiguity across model families.

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Next steps

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Additional resources