# magistral-small-2509

Calls to the model magistral-small-2509 on Mistral stopped working on July 31, 2026.

Mistral retired model magistral-small-2509 on July 31, 2026. Calls to this model fail since that date. The change took effect following an announcement on April 30, 2026.

## The error Mistral returns once magistral-small-2509 is gone

HTTP 400

```json
{"object":"error","message":"Invalid model: magistral-small-2509","type":"invalid_model","param":null,"code":"1500"}
```

## What to use instead

Mistral recommends migrating to Mistral Small 4.

- API: Mistral (api.mistral.ai)
- Model: magistral-small-2509
- Kind: Model retirement
- Announced: April 30, 2026
- Takes effect: July 31, 2026
- Calls after that day: fail
- Calls it hits: `model magistral-small-2509`
- Source: [Lifecycle page](https://docs.mistral.ai/getting-started/models/models_overview/)
- Verified: November 6, 2026, against Mistral's own pages
- Page: https://www.okapi.bot/models/mistral/magistral-small-2509/

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