ChatRail

ChatRail MCP server

Operate a ChatRail workspace from Claude, Cursor, VS Code and any other Model Context Protocol client. Check the health of your WhatsApp connections, look up groups, trace why a message failed, manage scheduled messages and replay webhook deliveries without leaving your editor.

ChatRail is a WhatsApp API for developers: send and receive WhatsApp messages over HTTP from a number you already have. See the MCP documentation for the full reference.

Privacy by design

• Message bodies, recipient phone numbers and credentials are never returned by any tool.
• Tools that change state return a preview first and apply only when called again with confirm: true.
• Every call is scoped to one workspace and recorded in its audit log.

Two ways to connect

1. Hosted server with OAuth (recommended)

Point any client that supports remote MCP servers at:

https://www.chatrail.dev/v1/mcp

Your client opens a browser window where a workspace owner, admin or developer approves access. Nothing to install and no key to copy.

Claude Code

claude mcp add --transport http chatrail https://www.chatrail.dev/v1/mcp

Cursor (~/.cursor/mcp.json)

{
  "mcpServers": {
    "chatrail": { "url": "https://www.chatrail.dev/v1/mcp" }
  }
}

VS Code (.vscode/mcp.json)

{
  "servers": {
    "chatrail": { "type": "http", "url": "https://www.chatrail.dev/v1/mcp" }
  }
}

2. Local stdio server with an API key

For clients that only run local servers, or when you would rather use an API key. This package runs on your machine and forwards requests to the hosted server.

1. In the ChatRail dashboard, create a workspace API key with the mcp:read scope. Add mcp:write if the assistant may reschedule, cancel, react or replay.
2. Add the server to your client.

Claude Desktop (claude_desktop_config.json)

{
  "mcpServers": {
    "chatrail": {
      "command": "npx",
      "args": ["-y", "chatrail-mcp"],
      "env": { "CHATRAIL_API_KEY": "cr_live_..." }
    }
  }
}

The package is published on npm as chatrail-mcp, so npx fetches it from the registry. If you need a version that is not published yet, run it straight from the repository instead:

"args": ["-y", "github:chatrail/chatrail_mcp"]

Docker

docker build -t chatrail-mcp .
docker run -i --rm -e CHATRAIL_API_KEY=cr_live_... chatrail-mcp

Variable	Required	Description
CHATRAIL_API_KEY	Yes, to call tools	Workspace API key with mcp:read (and optionally mcp:write).
CHATRAIL_MCP_URL	No	Override the endpoint. Defaults to https://www.chatrail.dev/v1/mcp.

Without a key the server still starts and lists its tools, so you can inspect it before signing up.

Tools

Tool	Scope	What it does
list_connections	read	Every WhatsApp connection in the workspace with its state and health.
get_connection	read	One connection with its state, health and recent state history.
list_whatsapp_groups	read	Groups visible to a connected number, with ids and participant counts.
get_whatsapp_group	read	Name, description, settings and member counts for one group.
list_messages	read	Recent messages with their delivery state.
get_message	read	One message and its delivery timeline.
explain_message_failure	read	A structured explanation of why a message failed.
list_scheduled_messages	read	Messages waiting to be sent, soonest first.
list_webhook_deliveries	read	Recent webhook deliveries and their outcomes.
reschedule_message	write	Change when a scheduled message is sent. Previews first.
cancel_scheduled_message	write	Cancel a message that has not been sent. Previews first.
react_to_message	write	Set or remove an emoji reaction on a message. Previews first.
replay_webhook	write	Requeue a dead or skipped webhook delivery. Previews first.

Plans

MCP access is included on the ChatRail Core + AI and Team plans. See pricing.

Development

npm install
npm run build
CHATRAIL_API_KEY=cr_test_... node dist/index.js

tools.json is the tool catalog served when no API key is configured. It is exported from the hosted server and should be refreshed when the hosted tools change.

Agent skill

ChatRail publishes a skill file that tells an agent when to use ChatRail, what a person has to set up, how to send and receive, and the rules for sending. This MCP server operates a workspace and cannot send messages, so the skill points to the REST API for sending.

Give your agent this line:

Read https://www.chatrail.dev/SKILL.md and follow it to set up ChatRail.

Or install it with the skills CLI, which installs agent skills from a GitHub repository:

npx skills add chatrail/chatrail_mcp

Or copy it into Claude Code by hand:

mkdir -p ~/.claude/skills/chatrail
curl -fsSL https://www.chatrail.dev/SKILL.md -o ~/.claude/skills/chatrail/SKILL.md

The canonical file is https://www.chatrail.dev/SKILL.md. A copy lives in this repository at skills/chatrail/SKILL.md so tools that install skills from GitHub can find it.

Links

• Website: https://www.chatrail.dev
• MCP docs: https://www.chatrail.dev/mcp
• API reference: https://www.chatrail.dev/api-reference
• Authentication: https://www.chatrail.dev/auth.md
• Agent skill: https://www.chatrail.dev/SKILL.md

License

MIT