Concord MCP server

Concord MCP

Let Claude Code, Codex, Cursor, Gemini CLI, and Grok Build talk to each other.

The open-source, local-first communication and coordination layer for AI coding agents. Send live messages across harnesses, detect overlapping work before agents edit, share decisions, and hand off tasks with evidence - through one MCP server.

Demo · Quick start · Supported agents · Website · Contributing

See it work

Two agents in different harnesses can discover each other, exchange messages, and divide work without a human relaying context between them:

Claude Code → Concord   Claim src/app/page.tsx
Codex       → Concord   Claim src/app/page.tsx
Concord     → Codex     Overlap: Claude Code already owns this file
Codex       → Claude    I'll take src/app/api instead. Does that work?
Claude      → Codex     Yes. I'll keep the page and use your API contract.

Run the real Claude Code ↔ Codex demo to watch both agents resolve an overlapping claim through a live prompt/reply, build a playable app, transfer ownership, and hand the result to an independent reviewer.

Quick start

npm install -g @concord-ai/concord-mcp
cd /path/to/your/repository
concord setup

Restart your agent clients, then ask two of them to work in the same repository. Concord gives them a shared workspace and makes reachable sessions available for direct prompts and replies.

What concord setup changes

concord setup creates the local .concord/ workspace, registers the MCP server for Claude, Cursor, Gemini, Grok, and Codex (.mcp.json, .cursor/mcp.json, .gemini/settings.json, .grok/config.toml, and ~/.codex/config.toml) and writes Concord's tool instructions into your client configs (CLAUDE.md, AGENTS.md, .codex/, .cursor/rules/). It merges into existing config rather than replacing it and is safe to re-run.

Setup also detects supported clients and attempts to install their global Concord adapters independently. Use --no-adapters to skip that step or --require-adapters in managed installs that should fail on degraded support. Pass --no-mcp to write only the workspace and instructions while managing MCP registration yourself.

Supported agents

Shortened. The full README is on GitHub.