Alphorn

Local

docs.alphorn.devCommunication0Updated 2w ago

About Alphorn

Alphorn MCP Server connects AI agents to Alphorn, an open-source notification router. It is for workflows that need to report task completion, failure, or a request for input through configured channels, and works with hosted or self-hosted Alphorn.

Key features

01Send notices with send_notification
02Set titles, priorities, and tags
03Route notices using Alphorn filters
04Connect to hosted or self-hosted Alphorn

Use cases

01Notify when a coding task finishes
02Alert people when a task fails or is blocked
03Request a decision from a person
04Route alerts to channels by priority

MCP support

The MCP server exposes the send_notification tool, which sends messages to an Alphorn webhook. Alphorn can route them to configured channels such as Slack, Telegram, Discord, email, SMS, and push.

Configuration

Local server config is the same for every client. Copy it into your client’s MCP config file.

mcp.json · Universal config

{
  "mcpServers": {
    "alphorn-dev": {
      "command": "npx",
      "args": [
        "-y",
        "@alphorn/mcp"
      ],
      "env": {
        "ALPHORN_WEBHOOK_URL": "<ALPHORN_WEBHOOK_URL>",
        "ALPHORN_API_KEY": "<ALPHORN_API_KEY>"
      }
    }
  }
}

Run commandnpx -y @alphorn/mcp

Environment variables to set

ALPHORN_WEBHOOK_URLSecretWebhook Endpoint URL, e.g. https://app.alphorn.dev/n/V1StGXR8_Z5jdHi6B-myT

ALPHORN_API_KEYSecretWebhook API key (alp_...), if the webhook requires one

Local servers need a runtime on your machine (e.g. Node.js 18+). Config file locations differ by client; see your client’s docs.

Packages

npm@alphorn/mcp0.1.1stdio

Tools

Saved tool list · updated 2w ago

Parameter	Type	Required	Description
tags	array	No	Tags the user can filter and route on, e.g. ["ai-agent", "completed"].
title	string	No	Short title. Start with the project name, e.g. "my-app - tests passing".
message	string	Yes	What happened and what you need from the user, in one or two sentences.
priority	integer	No	1 (lowest) to 5 (urgent). Use 2 when finished, 3 when you need input, 4 when blocked or failed.

Details

From the project README

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.

Claude Desktop, Cursor, and other JSON-configured clients

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

# ~/.codex/config.toml
[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_..." }

Tool

`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

pnpm install
pnpm test   # builds, then runs the tests against a local fake endpoint

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

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An open protocol that defines how AI applications connect to external tools and data in a uniform way. Clients talk to the model; MCP servers provide tools, resources and prompt templates. They exchange standard messages, so one server can be reused by many clients.