Module mcp_server 

Construct MCP server — exposes Construct’s built-in tools over the MCP Streamable HTTP transport (JSON-RPC 2.0 + SSE) so external CLIs (Claude Code, Codex, OpenCode, Gemini CLI) can share one local backend.

The MCP server runs as an in-process tokio task inside the main construct daemon (see src/gateway/mod.rs::run_gateway). External clients discover it through ~/.construct/mcp.json, written by the gateway as soon as the MCP task finishes binding to its ephemeral port.

This module contains the router, session store, tool registry, and ProgressSink that publishes notifications/progress events onto the originating SSE stream.

Design notes:

• One daemon, many sessions; sessions are in-memory only.
• Auth is a session_id + bearer token pair; no persistence.
• MCP keeps its own ephemeral port and its own auth pair — it does NOT share the gateway’s listener or pairing model.
• Tools are enumerated once at startup via registry::build_tools_with_runtime (config-aware + wired to live runtime handles) so every tool the gateway can run is also exposed to MCP clients. registry::build_default_tools and registry::build_tools_with_config are retained as the degraded fallback and the test entry point.

Re-exports

pub use runtime::RuntimeHandles;

pub use server::McpServerHandle;

pub use server::run_daemon;

pub use server::serve_on;

pub use session::ProgressEvent;

Modules

progress

ProgressSink implementation that publishes MCP notifications/progress JSON-RPC messages onto a per-request channel. The HTTP handler wires the receiver end into an SSE stream that ships events back to the client.

progress_wrap

Thin wrapper that adds start + finish progress notifications around an underlying tool’s execute() body.

registry

Tool registry used by the MCP daemon.

runtime

Runtime handles the MCP server may optionally receive from the main daemon.

server

Axum-based MCP daemon.

session

Session state for the MCP daemon.

skills_tools

Skill meta-tools exposed by the in-process MCP server.