mcpr (CLI binary)

mcpr is a sidecar primitive in the envoy / pgbouncer mold. The launched PID is the proxy itself — your host process supervisor (systemd, Docker, Node child_process.spawn, terminal) owns the lifecycle.

• proxy: mcpr proxy run <config> — runs the MCP gateway in the foreground. SIGTERM drains gracefully.
• relay: mcpr relay run <config> — tunnel relay server that accepts WebSocket connections and assigns subdomains. One per machine.

All state (lockfiles, config snapshots, sqlite store) lives under ~/.mcpr/.

Module Structure

Three-layer architecture: render (terminal output), logic (data operations), cmd (thin command dispatch).

mcpr-cli/src/
+-- main.rs           # Entry point, gateway runtime
+-- state.rs          # AppState (axum host container wrapping ProxyState)
+-- proxy.rs          # Axum fallback handler → mcpr_core pipeline
+-- config.rs         # CLI args (clap), TOML config, subcommands
+-- render.rs         # All terminal output — tables, colors, formatting
+-- admin.rs          # Health/readiness admin server
+-- proxy_lock.rs     # Per-proxy lockfiles under ~/.mcpr/proxies/
+-- relay_lock.rs     # Singleton relay lockfile under ~/.mcpr/relay/
+-- logic/            # Core business logic (no printing)
|   +-- proxy.rs      #   Proxy lifecycle (stop, reload, list, delete)
|   +-- relay.rs      #   Relay lifecycle (stop, status)
|   +-- query.rs      #   DB engine, time parsing, threshold parsing
+-- cmd/              # Thin command handlers (logic → render)
    +-- proxy.rs      #   Proxy lifecycle commands
    +-- relay.rs      #   Relay lifecycle commands
    +-- observe.rs    #   Observability commands (logs, stats, sessions, …)
    +-- store.rs      #   Store maintenance commands
    +-- setup.rs      #   Interactive setup flow (mcpr proxy setup)

The proxy engine (pipeline, middleware, ProxyState, forwarding, rewrite, SSE, health) lives in mcpr_core::proxy. This binary assembles a ProxyState + ProxyPipeline at boot, wires them into axum via AppState, and drives every request through AppState::pipeline.run.

The event bus (routes ProxyEvent to sinks) lives in mcpr_core::event; sink implementations (stderr, sqlite, cloud) live in mcpr_integrations. This binary just registers them via EventManager.