Update Thread
Update a thread. This is the autosave path — called once per turn.
Authorizations
Enter your MeshAPI key (rsk_...) — sent as Authorization: Bearer <key>.
Headers
Dated version of the API contract to pin this request to. Omit it and the request is served under 2026-08 — the oldest supported version, so an existing integration is never moved by a release. A malformed or unsupported value is rejected with 400 invalid_api_version rather than falling back silently. The version actually served is echoed as X-Mesh-Version on every response, including errors.
2026-08 Path Parameters
Body
Every field optional; only what is sent is written.
messages replaces the whole list rather than appending. The client already
holds the authoritative thread in memory (it is what the user is looking at),
and an append endpoint would need to resolve conflicts between two tabs — a
problem a last-writer-wins replace simply does not have.
Response
Successful Response