# gpt-5.1

Calls to the model gpt-5.1 on OpenAI stop working on April 1, 2027.

On April 1, 2027, model gpt-5.1 will be retired. This change affects calls using model gpt-5.1, as well as gpt-5.1-2025-11-13. After that date, these calls will fail.

## The error OpenAI returns once gpt-5.1 is gone

HTTP 404

```json
{"error":{"message":"The model `gpt-5.1` 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-6-sol, which is the replacement recommended by OpenAI.

- API: OpenAI (api.openai.com)
- Model: gpt-5.1
- Released: November 13, 2025 (models.dev)
- Kind: Model retirement
- Takes effect: April 1, 2027
- Calls after that day: fail
- Calls it hits: `model gpt-5.1`
- 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/gpt-5.1/

## OpenAI's words

> Shutdown date: Apr 1, 2027; Model / system: gpt-5.1 | gpt-5.1-2025-11-13; Recommended replacement: gpt-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