Assistants API threads, messages and runs removed on 2026-08-26
- Provider
- OpenAI
- Endpoint
* /v1/threads/**- Effective
- 2026-08-26
- Severity
- critical
- Change
- version-sunset
- Status
- verified
What changed
OpenAI removed the Assistants API on 2026-08-26, one year after its 2025-08-26 deprecation notice, including the threads, messages and runs endpoints that go with it (/v1/threads/**). Calls to them no longer work. The replacement is the Responses API plus the Conversations API. The assistants endpoints themselves are covered by openai-assistants-api-shutdown.
What to do
Move assistants to prompts (configuration created in the dashboard), threads to Conversations, and runs to Responses (send input items or a conversation id to the Responses API), and run the tool-call loop in your own code. Thread messages can no longer be fetched from the API, so read history from your own stored copy.
Sources
Check your code
npx shapi-cli scan .shapi scan lists the call sites this change affects; shapi fix repairs them test-first when the advisory has an automatic fix. All advisories · Markdown · OSV · JSON