Changelog

Unreleased

Thread-centric streaming (v3) — client.threads.stream() returns an AsyncThreadStream (or SyncThreadStream) context manager that owns one SSE or WebSocket connection for the lifetime of a thread session.
Typed projections — thread.messages, thread.tool_calls, thread.values, and thread.extensions[name] all share the same underlying transport connection. Iterating multiple projections concurrently expands the server-side filter union without opening additional connections.
Scoped subgraph handles — thread.subgraphs (alias thread.subagents) yields one ScopedStreamHandle per direct child invocation, each exposing .messages, .tool_calls, and .subgraphs scoped to that namespace.
WebSocket transport — pass transport="websocket" to client.threads.stream() to use a WebSocket connection instead of SSE (async client only).
Automatic reconnect — the shared SSE fan-out and the lifecycle watcher both reconnect on transport drops, replaying missed events via a since cursor and deduplicating by event_id.
thread.agent.get_tree() — fetches the assistant graph definition for the current session's assistant_id with optional xray depth control.
thread.run.respond() — resumes a run after a server-side interrupt, resolving the outstanding InterruptPayload by interrupt_id.
thread.output — awaitable that resolves to the terminal thread state values dict after the run lifecycle completes.

client.threads.stream() now accepts transport="sse" (default) or transport="websocket" in place of the previous transport-agnostic default.

The v3 streaming surface (AsyncThreadStream, SyncThreadStream, and all projection classes) is new in this release. The existing client.runs.stream() (v2) surface is unchanged and remains fully supported.
thread_id is minted client-side (UUIDv4) when not provided; the server creates the thread row lazily on the first run.start.