API
Comment on a thread
Write to the team, not the sender.
POST/threads/{id}/comments
Runs the real call on your workspace.
POST /threads/{id}/comments
Write to the team, not the sender.
Example
Needs threads:write. body is up to 10,000 characters, and mentions holds up to 20 user ids from the team of the thread. Each person mentioned is emailed. Answers 201 with the comment.
curl -X POST "$OE/threads/thr_7c1e4a90/comments" -H "$AUTH" -H "Content-Type: application/json" \ -d '{ "body": "Grace, can you take this one? They want the invoice sent again.", "mentions": ["usr_2f9c1d"] }'{ "object": "thread_comment", "id": "tcm_5e0b9c7a2d4f4e1b8a6c3d2e1f0a9b8c", "threadId": "thr_7c1e4a90", "author": { "object": "team_member", "id": "usr_8a41be", "name": "Ada Lovelace", "email": "[email protected]" }, "body": "Grace, can you take this one? They want the invoice sent again.", "mentions": [{ "object": "team_member", "id": "usr_2f9c1d", "name": "Grace Hopper", "email": "[email protected]" }], "createdAt": "2026-10-14T09:15:02.000Z", "editedAt": null}Mentioning somebody who cannot see the thread is a 422 invalid_parameter on mentions, and nothing is saved. Sending the same request twice adds two comments.
A key acts for the workspace owner. A key limited to particular addresses or domains reaches only the threads that arrived at them, and any other thread is a 404.