Prerequisites
Before configuring Claude Code with Vertex AI, ensure you have:- A Google Cloud Platform (GCP) account with billing enabled
- A GCP project with Vertex AI API enabled
- Access to desired Claude models (for example, Claude Sonnet 4.6)
- Google Cloud SDK (
gcloud) installed and configured - Quota allocated in desired GCP region
Sign in with Vertex AI
If you have Google Cloud credentials and want to start using Claude Code through Vertex AI, the login wizard walks you through it. You complete the GCP-side prerequisites once per project; the wizard handles the Claude Code side.The Vertex AI setup wizard requires Claude Code v2.1.98 or later. Run
claude --version to check.Enable Claude models in your GCP project
Enable the Vertex AI API for your project, then request access to the Claude models you want in the Vertex AI Model Garden. See IAM configuration for the permissions your account needs.
Start Claude Code and choose Vertex AI
Run
claude. At the login prompt, select 3rd-party platform, then Google Vertex AI.Follow the wizard prompts
Choose how you authenticate to Google Cloud: Application Default Credentials from
gcloud, a service account key file, or credentials already in your environment. The wizard detects your project and region, verifies which Claude models your project can invoke, and lets you pin them. It saves the result to the env block of your user settings file, so you don’t need to export environment variables yourself./setup-vertex any time to reopen the wizard and change your credentials, project, region, or model pins.
Region configuration
Claude Code can be used with both Vertex AI global and regional endpoints.Vertex AI may not support the Claude Code default models in all regions or on global endpoints. You may need to switch to a supported region, use a regional endpoint, or specify a supported model.
Set up manually
To configure Vertex AI through environment variables instead of the wizard, for example in CI or a scripted enterprise rollout, follow the steps below.1. Enable Vertex AI API
Enable the Vertex AI API in your GCP project:2. Request model access
Request access to Claude models in Vertex AI:- Navigate to the Vertex AI Model Garden
- Search for “Claude” models
- Request access to desired Claude models (for example, Claude Sonnet 4.6)
- Wait for approval (may take 24-48 hours)
3. Configure GCP credentials
Claude Code uses standard Google Cloud authentication. For more information, see Google Cloud authentication documentation.When authenticating, Claude Code will automatically use the project ID from the
ANTHROPIC_VERTEX_PROJECT_ID environment variable. To override this, set one of these environment variables: GCLOUD_PROJECT, GOOGLE_CLOUD_PROJECT, or GOOGLE_APPLICATION_CREDENTIALS.4. Configure Claude Code
Set the following environment variables:VERTEX_REGION_CLAUDE_* variable. See the Environment variables reference for the full list. Check Vertex Model Garden to determine which models support global endpoints versus regional only.
Prompt caching is automatically supported when you specify the cache_control ephemeral flag. To disable it, set DISABLE_PROMPT_CACHING=1. For heightened rate limits, contact Google Cloud support. When using Vertex AI, the /login and /logout commands are disabled since authentication is handled through Google Cloud credentials.
5. Pin model versions
Set these environment variables to specific Vertex AI model IDs. WithoutANTHROPIC_DEFAULT_OPUS_MODEL, the opus alias on Vertex resolves to Opus 4.6. Set it to the Opus 4.7 ID to use the latest model:
| Model type | Default value |
|---|---|
| Primary model | claude-sonnet-4-5@20250929 |
| Small/fast model | claude-haiku-4-5@20251001 |
Startup model checks
When Claude Code starts with Vertex AI configured, it verifies that the models it intends to use are accessible in your project. This check requires Claude Code v2.1.98 or later. If you have pinned a model version that is older than the current Claude Code default, and your project can invoke the newer version, Claude Code prompts you to update the pin. Accepting writes the new model ID to your user settings file and restarts Claude Code. Declining is remembered until the next default version change. If you have not pinned a model and the current default is unavailable in your project, Claude Code falls back to the previous version for the current session and shows a notice. The fallback is not persisted. Enable the newer model in Model Garden or pin a version to make the choice permanent.IAM configuration
Assign the required IAM permissions: Theroles/aiplatform.user role includes the required permissions:
aiplatform.endpoints.predict- Required for model invocation and token counting
Create a dedicated GCP project for Claude Code to simplify cost tracking and access control.
1M token context window
Claude Opus 4.7, Opus 4.6, and Sonnet 4.6 support the 1M token context window on Vertex AI. Claude Code automatically enables the extended context window when you select a 1M model variant. The setup wizard offers a 1M context option when it pins models. To enable it for a manually pinned model instead, append[1m] to the model ID. See Pin models for third-party deployments for details.
Troubleshooting
If you encounter quota issues:- Check current quotas or request quota increase through Cloud Console
- Confirm model is Enabled in Model Garden
- Verify you have access to the specified region
- If using
CLOUD_ML_REGION=global, check that your models support global endpoints in Model Garden under “Supported features”. For models that don’t support global endpoints, either:- Specify a supported model via
ANTHROPIC_MODELorANTHROPIC_DEFAULT_HAIKU_MODEL, or - Set a regional endpoint using
VERTEX_REGION_<MODEL_NAME>environment variables
- Specify a supported model via
- For regional endpoints, ensure the primary model and small/fast model are supported in your selected region
- Consider switching to
CLOUD_ML_REGION=globalfor better availability