Add /mcp to run and configure the bundled MCP server

[barkz]

Adds /mcp — inspect, configure, and run the bundled MCP server without leaving the REPL.

This work has been sitting on feat/mcp-command unmerged. It is being landed on its own so the flow-mapper branch reviews as one feature rather than two.

What it does

Command
/mcp status	Installed mcp version, whether it can actually run the server, and any running instance's pid, URL, uptime, and mode
/mcp config [client]	Paste-ready JSON for Claude Code, Claude Desktop, or Cursor
/mcp start	Runs the server detached over HTTP
/mcp stop	Terminates it

Two decisions worth knowing

start deliberately refuses stdio. stdio is a pipe pair between a client and the server it spawned — started from the REPL there would be no client on the other end, and the REPL already owns its own stdin and stdout. start therefore runs streamable-http (default) or sse, which a client attaches to by URL. Transport flags were added to glean_mcp.py to support this.

--name exists because of a silent collision. Glean ships its own hosted MCP server, and both would naturally register under the key glean. Pasting one over the other replaces it with no error — you simply end up with a different toolset than you expected. /mcp config --name glean-cli keeps both, and the default form warns when it emits the colliding name.

Notes

• Binds 127.0.0.1 by default — a live server holds whatever credentials your config has
• The server outlives the REPL; state lives in ~/.gleancode/mcp.json and stale entries clear themselves
• mcp_control.py never imports the mcp package, so the REPL stays dependency-free
• 285 lines of tests in tests/test_mcp_control.py
• Docs: docs/MCP.md and docs/COMMANDS.md

🤖 Generated with Claude Code