Relay MCP server

Remote Model Context Protocol server for Relay, a business phone and SMS app for teams, built in Montreal.

It lets Claude, or any MCP client, work with your team's phone: list calls and texts, read call transcripts, search and update contacts, send an SMS from the team number, and draft call-routing flows.

This repository holds no server code: the server is hosted by Relay. Nothing to install on the server side.

Get an API key

1. Create a free account at https://app.yesrelay.com.
2. In the app, open Administration, then Integrations & API, and create a key.
3. The key starts with rk_live_ and is shown once. Keep it in a secrets manager.

Revoking the key in the app cuts MCP and REST access at the same instant.

Connect a client

Claude Code

claude mcp add --transport http relay https://api.yesrelay.com/api/mcp \
  --header "Authorization: Bearer rk_live_..."

Claude Desktop

claude_desktop_config.json, through mcp-remote:

{
  "mcpServers": {
    "relay": {
      "command": "npx",
      "args": ["mcp-remote", "https://api.yesrelay.com/api/mcp",
               "--header", "Authorization:${AUTH}"],
      "env": { "AUTH": "Bearer rk_live_..." }
    }
  }
}

Any other client

Point it at https://api.yesrelay.com/api/mcp with the Authorization header above.

Tools

Calls and messages

Contacts and team

Flow (call routing, Business and Scale plans)

No tool publishes a flow. An agent can draft and check a call path; a person puts it live from the app.

Safeguards

A text sent through MCP goes through the same checks as a text sent from the app:

What you can do also follows your plan: sending texts needs a paid plan, and the Flow tools need Business or Scale.

Limits

Each message in a JSON-RPC batch counts as one request.

Troubleshooting

The client shows a read error, or curl fails with error 56 ("chunk hex-length"). Some antivirus software that inspects HTTPS traffic corrupts MCP responses; we have seen it with Avast. The server answered correctly. Exclude api.yesrelay.com from your antivirus HTTPS scanning, then try again.

401 Invalid API key. The key is missing, revoked or expired. Create a new one in the app.

Also available

• REST API: https://api.yesrelay.com/api/v1, reference at https://api.yesrelay.com/docs
• Signed webhooks (HMAC SHA-256) for call and SMS events

Support

hello@yesrelay.com