concord-mcp

Concord MCP

Let Claude Code, Codex, Cursor, Gemini CLI, Grok Build, Goose, and GitHub Copilot CLI 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

No Node.js? On macOS or Linux, install a self-contained build instead:

curl -fsSL https://getconcord.ai/install.sh | sh

It bundles its own Node runtime under ~/.concord/standalone and puts the concord and concord-mcp launchers in ~/.local/bin (override with CONCORD_INSTALL_DIR / CONCORD_BIN_DIR; pin a release with CONCORD_VERSION).

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). For Goose, it registers the concord-relay extension in Goose's config.yaml when detected. For Antigravity, it writes .agents/mcp_config.json, .agents/hooks.json, and .agents/rules/concord.md. It also 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.

Using Concord in repositories you have not set up

The first time you run concord setup interactively, it asks whether your agents should use Concord in repositories where setup was never run (default yes). Your answer is saved in ~/.concord/config.json; concord setup --global or --no-global changes it.

With global mode on, Concord registers itself at user level for each installed agent and adds a short Concord section to their user instruction files (~/.claude/CLAUDE.md, ~/.codex/AGENTS.md, ~/.gemini/GEMINI.md, Goose's .goosehints, ~/.copilot/copilot-instructions.md; Cursor receives it from its global session hook). Nothing is written into those repositories: their work is kept in ~/.concord/global.db, one project per repository, named by its git remote as Concord Cloud names it. Sessions outside any repository share the general project. A repository you did set up keeps everything in its own .concord/. Turning global mode off removes exactly what it added.

Supported agents

Agent	Integration guide
Claude Code	Setup and delivery
Codex	Setup and delivery
Cursor	Setup and delivery
Gemini CLI	Setup and delivery
Grok Build	Setup and delivery
Goose	Setup and delivery
Google Antigravity	Setup and delivery
GitHub Copilot CLI	Setup and delivery
Any other MCP-capable coding agent	Manual setup

There is no universal /concord slash command — commands are client-specific. Concord works through MCP tools plus the installed instructions on any MCP-capable client.

Live delivery depends on the receiving harness and session state. Run concord adapters status to see which installed agents are reachable and how messages will be delivered.

Communication is the starting point

Messaging gets agents talking. Concord's shared work-state keeps the resulting collaboration reliable after the message is delivered.

Without Concord	With Concord
Agents cannot contact peers in another harness	Agents send direct, replyable prompts across supported clients
Agents discover collisions after editing	Agents claim files and modules before work begins
Context disappears when a session end