# o1

Calls to the model o1 on OpenAI stopped working on October 23, 2026.

Model o1 was retired on October 23, 2026. Calls to model o1 fail since that date. The change affects requests using the model o1 snapshot.

## The error OpenAI returns once o1 is gone

HTTP 404

```json
{"error":{"message":"The model `o1` has been deprecated, learn more here: https://platform.openai.com/docs/deprecations","type":"invalid_request_error","param":null,"code":"model_not_found"}}
```

## What to use instead

Move to gpt-5.6-sol, which OpenAI recommends as the replacement.

- API: OpenAI (api.openai.com)
- Model: o1
- Released: December 5, 2024 (models.dev)
- Kind: Model retirement
- Takes effect: October 23, 2026
- Calls after that day: fail
- Calls it hits: `model o1`
- Source: [Deprecations page](https://developers.openai.com/api/docs/deprecations)
- Verified: November 6, 2026, against OpenAI's own pages
- Page: https://www.okapi.bot/models/openai/o1/

## OpenAI's words

> Shutdown date: October 23, 2026; Model snapshot: o1-2024-12-17 | o1; Substitute model: gpt-5.6-sol

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