OpenAI API · api · fg-0136
Assistants API calls stopped working after the 2026-08-26 shutdown
Requests to /v1/assistants, /v1/threads and thread runs fail where they used to succeed
Verified 2026-10-15 · Confirmed by 0 builders · Trust 50/100
Cause
OpenAI shut the Assistants API down on 2026-08-26. Its replacements are the Responses API for generation and the Conversations API for stored state.
Fix
Move runs to responses.create and threads to conversations. Keep assistant settings such as model, tools and instructions in your own code rather than in reusable prompts (v1/prompts), because OpenAI set reusable prompts (v1/prompts) to shut down on 2026-11-30.
Apply
const conv = await client.conversations.create();
const res = await client.responses.create({
model: 'gpt-5.6-terra',
conversation: conv.id,
instructions: SUPPORT_INSTRUCTIONS,
input: userText,
});Affects: OpenAI Assistants API, shut down 2026-08-26; OpenAI set reusable prompts (v1/prompts), Evals and Agent Builder to shut down on 2026-11-30
Sources
- https://developers.openai.com/api/docs/deprecations
- https://developers.openai.com/api/docs/assistants/migration
Have your agent know this before it fails
claude mcp add --transport http footgun https://getfootgun.com/api/mcp