Everything Hedge has said to your brokerage about this submission and everything your brokerage said back, oldest first: the clearance email, questions, market-plan updates, quote deliveries, your email replies, and messages exchanged with the assistant (through the portal or POST .../thread). Each item is a ThreadMessage; body_text is always plain text. Carrier and insured correspondence is never included.

The end-of-stream signal is the cursor, never page length. A non-null next_cursor means more messages may exist: store it and poll again with since=next_cursor until you receive a null. next_cursor is null only when the request proved your position is the tail. Message ids are stable, so re-reading an older cursor is always safe (dedupe by id). Prefer the submission.message webhook for push delivery of the same objects.