Get a conversation thread by id

Returns a conversation thread: its metadata plus the inbound and outbound messages that belong to it, interleaved in time order (oldest first). A thread spans both received emails and your sends, so an agent can reconstruct an entire back-and-forth from one call instead of walking reply headers.

Each message carries a direction (inbound | outbound) and an id; fetch the full message via /emails/{id} or /sent-emails/{id} accordingly. Bodies are omitted here to keep the thread view lightweight.

Discover a thread id from the thread_id field on any email or sent-email (list or detail). The message list is capped; compare message_count against messages.length to detect truncation.