Conversation messages

PAP message IDs are user-global idempotency keys. Generate one with at least 128 random bits, retain the complete Message, and retry that same object after an ambiguous network failure. Reusing its ID with different content is a message_id_conflict.

Python and TypeScript both expose ConversationClient. It validates opaque IDs, supports text, data, and context, bounds response bodies, rejects duplicate JSON members, surfaces company error codes without including response bodies, and can request replies with cursor and wait. Authentication remains in DpopHttpClient and never enters model-visible tool inputs or results.

TypeScript additionally propagates caller-owned AbortSignal cancellation. Ordered JSON event reads are implemented separately in the conversation events flow. SSE, handoff, Direct Conversations, authorization changes, and active close requests remain separate milestones.

Run the Pydantic AI example. See upstream Conversations.