# claude-sonnet-4-5

Calls to the model claude-sonnet-4-5 on Vertex AI stop working on November 30, 2026.

## The error Vertex AI returns once claude-sonnet-4-5 is gone

HTTP 404

```json
{"error":{"code":404,"message":"Publisher model `projects/{project}/locations/{region}/publishers/google/models/claude-sonnet-4-5` was not found or your project does not have access to it. Ensure you are using a valid model name and that the model is available in the specified region.","status":"NOT_FOUND"}}
```

- API: Vertex AI (aiplatform.googleapis.com)
- Model: claude-sonnet-4-5
- Released: September 29, 2025 (models.dev)
- Kind: Model retirement
- Takes effect: November 30, 2026
- Calls after that day: fail
- Calls it hits: `model claude-sonnet-4-5`
- Source: [Deprecations page](https://docs.cloud.google.com/gemini-enterprise-agent-platform/models/deprecations/partner-models)
- Verified: November 6, 2026, against Vertex AI's own pages
- Page: https://www.okapi.bot/models/vertex-ai/claude-sonnet-4-5/

Okapi finds the calls this change hits in your repo and opens the pull request with the fix: https://github.com/apps/okapi-agent