Slack Webhook

Post messages to Slack channels using incoming webhooks.

A Model Context Protocol (MCP) server that enables LLM applications like Claude Desktop to send messages to Slack channels via incoming webhooks.

- Send plain text or markdown-formatted messages to Slack
- Simple and secure webhook URL management
- Built with Deno for modern TypeScript development
- Full test coverage

- Denoinstalled on your system
- A Slack workspace with incoming webhooks enabled
- Claude Desktop (or another MCP-compatible client)

git clone https://github.com/yourusername/slack-webhook-mcp.git cd slack-webhook-mcp

cp .env.example .env # Edit .env and add your webhook URL

{ "mcpServers": { "slack-webhook": { "command": "deno", "args": ["run", "--allow-net", "--allow-env", "--allow-read", "/path/to/slack-webhook-mcp/src/index.ts"], "env": { "SLACK_WEBHOOK_URL": "https://hooks.slack.com/services/YOUR/WEBHOOK/URL" } } } }

You can also compile the server to a standalone executable:

Then use the binary in your configuration:

{ "mcpServers": { "slack-webhook": { "command": "/path/to/slack-webhook-mcp/slack-webhook-server", "env": { "SLACK_WEBHOOK_URL": "https://hooks.slack.com/services/YOUR/WEBHOOK/URL" } } } }

Once configured, you can use the following tool in Claude Desktop:

Send a message to your configured Slack channel.

- message(required): The message text to send
- webhook_url(optional): Override the default webhook URL
- format(optional): Message format - "text" or "markdown" (default: "markdown")

- "Send a Slack message saying the deployment was successful"
- "Notify the team on Slack that the tests are passing"
- "Send 'Build failed: timeout in test suite' to Slack with plain text format"

# Run in development mode with auto-reload deno task dev # Run tests deno task test # Run tests with coverage deno task test:coverage # Type checking deno task check # Linting deno task lint # Format code deno task fmt # Build standalone executable deno task build

slack-webhook-mcp/ ├── src/ │ ├── index.ts # Entry point │ ├── server.ts # MCP server implementation │ ├── tools/ │ │ ├── slack_webhook.ts # Slack webhook tool │ │ └── slack_webhook_test.ts # Tool tests │ ├── types.ts # TypeScript types │ └── index_test.ts # Integration tests ├── deno.json # Deno configuration ├── README.md # This file └── .env.example # Environment variables example

- Never commit your.envfile or webhook URLs to version control
- Webhook URLs are validated to ensure they match Slack's format
- All errors are handled gracefully without exposing sensitive information
- Fork the repository
- Create your feature branch (git checkout -b feature/amazing-feature)
- Run tests and ensure they pass (deno task test)
- Commit your changes (git commit -m 'Add amazing feature')
- Push to the branch (git push origin feature/amazing-feature)
- Open a Pull Request

This project is licensed under the MIT License - see the LICENSE file for details.

- Built using theModel Context Protocol SDK
- Powered byDeno
- Integrates withSlack Incoming Webhooks

A server for sending multi-platform notifications and creating interactive AI workflows, with support for Telegram, webhooks, and synchronous user interactions.