# claude-sonnet-4-5-20250929

Calls to the model claude-sonnet-4-5-20250929 on Anthropic stop working on November 30, 2026.

On November 30, 2026, the model claude-sonnet-4-5-20250929 will be retired. Anthropic deprecated the model on September 30, 2026. Any calls using model claude-sonnet-4-5-20250929 after November 30, 2026 will fail.

## The error Anthropic returns once claude-sonnet-4-5-20250929 is gone

HTTP 404

```json
{"type":"error","error":{"type":"not_found_error","message":"model: claude-sonnet-4-5-20250929"}}
```

## What to use instead

Move to claude-sonnet-5-5, as recommended by Anthropic.

- API: Anthropic (api.anthropic.com)
- Model: claude-sonnet-4-5-20250929
- Released: September 29, 2025 (models.dev)
- Kind: Model retirement
- Announced: September 30, 2026
- Takes effect: November 30, 2026
- Calls after that day: fail
- Calls it hits: `model claude-sonnet-4-5-20250929`
- Source: [Deprecations page](https://platform.claude.com/docs/en/about-claude/model-deprecations)
- Verified: November 6, 2026, against Anthropic's own pages
- Page: https://www.okapi.bot/models/anthropic/claude-sonnet-4-5-20250929/

## Anthropic's words

> API model name: claude-sonnet-4-5-20250929; Current state: Deprecated; Deprecated: September 30, 2026; Tentative retirement date: November 30, 2026

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