Core primitives

• Thread: A conversation between a user and the Codex agent. Threads contain turns.
• Turn: A single user request and the agent work that follows. Turns contain items and stream incremental updates.
• Item: A unit of input or output (user message, agent message, command runs, file change, tool call, and more).

Use the thread APIs to create, list, or archive conversations. Drive a conversation with turn APIs and stream progress via turn notifications.