Cerebras
disable_reasoning body parameter removal on POST /v1/chat/completions
Stopped workingSubscribe to CerebrasShare
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.
Calls it hits
POST /v1/chat/completionsbody parameter disable_reasoning
What to use instead of these calls
Use reasoning_effort="none" to disable reasoning instead.
In Cerebras's words
The disable_reasoning parameter will no longer be supported after July 21, 2026.
Facts
- API
- Cerebras
api.cerebras.ai - Kind
- Parameter removal
- Announced
- March 24, 2026
- Takes effect
- July 21, 2026
- Calls after that day
- Fail
- Source
- Announcement
- Last updated
- Verified
- , against Cerebras's own pages
Questions
When does this change take effect?
Calls to POST /v1/chat/completions, body parameter disable_reasoning on Cerebras stopped working on July 21, 2026.
What happens to calls after July 21, 2026?
They have failed since July 21, 2026.
How do I find the calls this hits in my code?
Okapi reads your repository, finds the calls this change hits and opens a pull request with the fix. It never commits to your branches: every change comes as a pull request you review.
You fixed this one by hand.
Okapi opens the pull request with the fix before the next breaking change reaches your code.