Start a thread with the default agent
Starts a new conversation thread: resolves the container, mints a threadId, and creates the thread’s first agent run there from the founding prompt (1–4000 chars) and optional fileIds (1–200). Omit spaceId for the caller’s private desk (the default); pass a spaceId to start the thread in a space, where every holder of space:contribute can read and continue it. Authorization: any real organization member (embed tokens and API keys have no desk → 404); a named space requires space:contribute (404 otherwise) and may never be a desk id (400 cannot_target_desk). Gated by AGENTS_ENABLED; disabled → 404. Returns 201 { threadId, runId, steered: false, status, spaceId }.
Authentication
Bearer authentication of the form Bearer <token>, where token is your auth token.
Request
The request that founds the thread (frozen into the first run’s snapshot).
The agent the thread talks to. Omit for the default agent. Every run in the thread (including rollover successors) executes this agent.
Files to attach to the first run. Omit for a prompt-only start.
Start the thread in this space instead of the caller’s private desk — everyone who holds space:contribute on it can then read and continue the thread. Requires space:contribute (404 otherwise). A desk id (me:…) is never a valid target (400 cannot_target_desk).
Response
The thread’s first run.