List agent messages
Every agent message in the store, newest first, each carrying the conversation it belongs to. THIS IS THE BATCH TRANSCRIPT READ. Without the filter it is a single paged sweep across ALL conversations, so reconciling a store’s chat history is one walk that you group by conversation_id yourself, NOT one request per thread. An audit of this API reported a missing batch route on the assumption that transcripts could only be read one conversation at a time; they cannot, and this is the route that already answers it. ?conversation_id= narrows it to a single thread when that is what you want. An EMPTY value is refused rather than read as “every conversation”, because a client building the query from a variable it forgot to set would otherwise receive the whole store’s transcript and read it as one thread. PAIR IT WITH GET /api/v1/agent-conversations, which carries the thread’s status, assignee and handoff state. This route carries the words; that one carries what the thread IS.
Authorizations
A secret API key. Publishable keys cannot reach this API. A key may carry an expiry, and an expired key is refused exactly like an unknown one, with a 401 that names no reason; check the key's expires_at in the dashboard rather than inferring it from a response. When a merchant rolls a key's secret they choose a grace window of up to 3 days, and for its duration BOTH the new secret and the one it replaced authenticate, so an integration moves over on its own deploy schedule instead of at the instant the button is pressed. Move before the window closes: after it, the old secret is refused. Nothing else about this contract moves with a roll. The key keeps its id and its scopes, so the only thing an integration updates is the credential itself.
Query Parameters
One conversation's turns. Omit it to read every conversation in the store, which is what this endpoint exists for: the per-conversation transcript was the only way to read messages, so reconciling N conversations cost 1+N requests against a rate budget this whole family shares. An EMPTY value is a 400 rather than "no filter", so a client building the query from a variable it forgot to set does not receive the whole store's transcript and read it as one thread.
Rows per page. Out of range is a 400 rather than a silent clamp, so a client asking for more than 100 learns it did not get it.
1 <= x <= 100The next_cursor from the previous page. Opaque: decode nothing from it and construct nothing by hand, since its encoding is not part of this contract. Omit it to read the first page.