## Summary - make the plan tool available by default by removing the feature flag and always registering the handler - drop plan-tool CLI and API toggles across the exec, TUI, MCP server, and app server code paths - update tests and configs to reflect the always-on plan tool and guard workspace restriction tests against env leakage ## Testing Manually tested the extension. ------ https://chatgpt.com/codex/tasks/task_i_68f67a3ff2d083209562a773f814c1f9
codex-app-server
codex app-server is the harness Codex uses to power rich interfaces such as the Codex VS Code extension. The message schema is currently unstable, but those who wish to build experimental UIs on top of Codex may find it valuable.
Protocol
Similar to MCP, codex app-server supports bidirectional communication, streaming JSONL over stdio. The protocol is JSON-RPC 2.0, though the "jsonrpc":"2.0" header is omitted.
Message Schema
Currently, you can dump a TypeScript version of the schema using codex generate-ts. It is specific to the version of Codex you used to run generate-ts, so the two are guaranteed to be compatible.
codex generate-ts --out DIR