Observe the pipeline through the MCP server

The desktop exposes its capabilities as MCP tools over app.App (ADR mcp-replaces-the-agent-facing-http-api), so a test asserts against a supported surface instead of desktop-pipeline.db. One loopback http server (on by default) serves webhook push (/hooks/…), the MCP server (/mcp), and the liveness probe (/api/status) on one port.

Pair this with the devserver skill: devserver acts (rewrites GitHub, pushes webhooks), these tools observe and reload.

1. Find the port and confirm the app is up

The HTTP port is written to the worktree's launch.env. Liveness stays a plain GET, because a JSON-RPC handshake is the wrong shape for "is it running?":