Threadline Mcp
Wire multiple coding agents into a zero-config relay so they can discover peers and exchange messages during builds.
Overview
Threadline MCP is a Build-phase MCP server that relays discoverable agent-to-agent messages over a zero-config WebSocket relay.
What is this MCP server?
- Zero-config stdio MCP package (threadline-mcp on npm) with optional relay URL override
- Discover other agents and send messages with replies over the Threadline relay
- Tune identity via THREADLINE_NAME and discovery via THREADLINE_CAPS (comma-separated capabilities)
- Default relay: wss://threadline-relay.fly.dev/v1/connect
- stdio transport suited to Claude Code, Cursor, and Codex MCP configs
- Package version 0.1.2
- stdio transport via npm identifier threadline-mcp
- 3 optional environment variables: THREADLINE_RELAY, THREADLINE_NAME, THREADLINE_CAPS
Community signal: 65 GitHub stars.
What problem does it solve?
Coordinating multiple AI agents still means manual handoffs and no standard way to discover who can handle a capability.
Who is it for?
Indie builders experimenting with multi-agent setups who want chat-style coordination without building a custom message bus.
Skip if: Teams that need guaranteed delivery, enterprise auth, or human team chat instead of machine-to-machine agent traffic.
What do I get? / Deliverables
Your agent registers on the relay, advertises caps, and can message other agents and read replies from your IDE MCP client.
- Registered agent identity on the Threadline relay
- MCP tools to discover peers and send or receive agent messages
- Capability-tagged presence via THREADLINE_CAPS for discovery
Recommended MCP Servers
Journey fit
Multi-agent collaboration is most common while building and extending agent tooling, which is why Build is the canonical shelf. Agent-tooling is where MCP bridges between autonomous agents—not a single-app frontend or backend task.
How it compares
Agent messaging relay over MCP, not a human WhatsApp-style room or a planning skill.
Common Questions / FAQ
Who is threadline-mcp for?
Solo and small-team builders wiring Claude Code, Cursor, or Codex to other autonomous agents via MCP.
When should I use threadline-mcp?
When two or more agents need to discover each other and exchange messages during build or ops workflows without custom networking.
How do I add threadline-mcp to my agent?
Add the npm MCP server threadline-mcp with stdio transport; set THREADLINE_CAPS and optionally THREADLINE_RELAY and THREADLINE_NAME in your client config.