App Server interface snapshot

This snapshot covers Codex App Server only; it is not a complete description of any desktop or IDE client.

Boundary

At the pinned commit, App Server runs a JSON-RPC message loop over stdio, Unix-socket, or WebSocket transports. The connection layer owns framing and connection lifecycle; the message processor converts wire requests into typed requests and dispatches them to processors for threads, turns, configuration, MCP, plugins, filesystems, and other domains.

Why this is a separate snapshot

• surface=server must not be mixed with surface=cli behavior.
• A protocol capability does not prove that a particular client adopted it.
• Published server source does not imply published client or hosted-service source.
• Available transports do not establish reconnect, ordering, or backward compatibility without experiments.

Claim: codex-source-app-server. The next step is a deterministic public-contract experiment across initialize → thread → turn → event → cancel.