Alphorn MCP Server
MCP server for Alphorn, the open-source notification router. It gives AI agents (Claude Code, Claude Desktop, Cursor, Codex, and any other MCP client) a send_notification tool, so an agent can tell you when a task finishes, fails, or needs your decision, on whatever channel you configured in Alphorn: Slack, Telegram, Discord, email, SMS, push, and more.
Works with the hosted service at app.alphorn.dev and with self-hosted Alphorn.
Setup
- Create a webhook in Alphorn and copy its Endpoint URL, plus its API key if you switched on Require API key (docs).
- Add the server to your MCP client with two environment variables:
| Variable | Value |
|---|
ALPHORN_WEBHOOK_URL | Endpoint URL, e.g. https://app.alphorn.dev/n/V1StGXR8_Z5jdHi6B-myT |
ALPHORN_API_KEY | Webhook API key (alp_...). Leave unset if the webhook does not require one. |
Claude Code
claude mcp add alphorn -s user \
-e ALPHORN_WEBHOOK_URL=https://app.alphorn.dev/n/V1StGXR8_Z5jdHi6B-myT \
-e ALPHORN_API_KEY=alp_... \
-- npx -y @alphorn/mcp
Claude Desktop (one-click bundle)
Download alphorn.mcpb from the latest release and open it. Claude Desktop asks for the Endpoint URL and API key.
Add to claude_desktop_config.json, ~/.cursor/mcp.json, or your client's MCP config:
{
"mcpServers": {
"alphorn": {
"command": "npx",
"args": ["-y", "@alphorn/mcp"],
"env": {
"ALPHORN_WEBHOOK_URL": "https://app.alphorn.dev/n/V1StGXR8_Z5jdHi6B-myT",
"ALPHORN_API_KEY": "alp_..."
}
}
}
}
OpenAI Codex CLI
[mcp_servers.alphorn]
command = "npx"
args = ["-y", "@alphorn/mcp"]
env = { ALPHORN_WEBHOOK_URL = "https://app.alphorn.dev/n/V1StGXR8_Z5jdHi6B-myT", ALPHORN_API_KEY = "alp_..." }
send_notification
| Argument | Type | Required | Description |
|---|
message | string | yes | What happened and what the agent needs from you (max 4,000 characters) |
title | string | no | Short title, e.g. my-app - tests passing (max 200 characters) |
priority | integer 1-5 | no | 2 = finished, 3 = needs input, 4 = blocked or failed, 5 = urgent |
tags | string[] | no | Tags to filter and route on in Alphorn, e.g. ["ai-agent", "completed"] |
The tool wraps Alphorn's send endpoint. For direct HTTP use, see the API reference and the OpenAPI 3.1 specification.
Use Alphorn's filters to decide where each notification goes, for example SMS only for priority 4 and above.
Development
Releasing
- Bump
version in package.json, server.json (both fields), manifest.json, and VERSION in src/server.ts.
npm publish --access public
- Push a
v<version> tag (or run the Publish to MCP Registry workflow): it publishes server.json to the MCP Registry via GitHub OIDC
pnpm bundle, then attach alphorn.mcpb to a GitHub release
License
AGPL-3.0-or-later