# disable_reasoning on POST /v1/chat/completions stops working

Calls to POST /v1/chat/completions, body parameter disable_reasoning on Cerebras stopped working on July 21, 2026.

On July 21, 2026, Cerebras removed support for the disable_reasoning body parameter on POST /v1/chat/completions. Requests that continue to pass this parameter fail since that date. The change affects all callers sending the disable_reasoning parameter to this endpoint.

## What to use instead

Use reasoning_effort="none" to disable reasoning instead.

- API: Cerebras (api.cerebras.ai)
- Kind: Parameter removal
- Announced: March 24, 2026
- Takes effect: July 21, 2026
- Calls after that day: fail
- Calls it hits: `POST /v1/chat/completions`, `body parameter disable_reasoning`
- Source: [Announcement](https://inference-docs.cerebras.ai/support/deprecation)
- Verified: November 6, 2026, against Cerebras's own pages
- Page: https://www.okapi.bot/providers/cerebras/breaking-changes/disable-reasoning-on-post-v1-chat-completions-stops-working/

## Cerebras's words

> The disable_reasoning parameter will no longer be supported after July 21, 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