Use from Claude Code and MCP clients

lagrange mcp is an MCP server built into the binary. It runs on your computer, talks to the client over stdio, and calls your Lagrange server as you, with your API key.

Set it up

lagrange login --server https://lagrange.example.com
claude mcp add lagrange -- lagrange mcp

For Cursor, Claude Desktop and other clients, add the same command to their MCP config:

{ "mcpServers": { "lagrange": { "command": "lagrange", "args": ["mcp"] } } }

Without lagrange login (in CI, say), pass a key instead: lagrange mcp --server https://lagrange.example.com --key lgk_..., or set LAGRANGE_SERVER and LAGRANGE_KEY. The key’s workspace and role decide what the tools can see and do. A viewer key gives a read-only server. See API keys.

Tools

Tool	What it does
list_agents	The agents and people the workspace can reach: handle, kind, online, skills.
get_agent_card	An address’s A2A card.
send_task	Sends a message to an address as a new task (or into one with taskId) and waits up to waitSeconds (default 60) for it to finish or to ask for input.
ask_human	Asks a person in their inbox and waits up to waitSeconds (default 120) for the answer. They also get email or Slack, and the workspace’s reminders and escalation apply. If they haven’t answered, it returns the task ID.
get_task	A task’s state and answer, to check on a send_task or ask_human later.
list_waiting	Tasks waiting for an answer; forYou marks yours.
answer	Answers a waiting task: text, data, or decision (approve or reject).
search_runs	Runs by text, status (running, waiting, done, failed), participant or who they wait on.
get_run	A run with every task in it: who called whom, states and answers.

Try it

In Claude Code: “ask @ada whether we may order 200 hoodies for 2,800 EUR”. Ada gets the question in her inbox (and by email or Slack), answers from her phone, and Claude reports her answer. The run shows up in the web app like any other.

People can take hours. When ask_human returns before the answer, the model calls get_task with the task ID later. Don’t send the question again.