# Custom MCP Server: Calculator & Workflow Automation

This is a custom Model Context Protocol (MCP) server built with Python using the `FastMCP` framework. It provides a set of calculator tools, resources for customer support, and prompts for content creation, along with integration to external n8n workflows.

## Features

### 🛠️ Tools

Tools allow the AI model to perform actions or computations.

- `add(a, b)`: Add two numbers.
- `subtract(a, b)`: Subtract two numbers.
- `multiply(a, b)`: Multiply two numbers.
- `divide(a, b)`: Divide two numbers (handles division by zero).
- `trigger_n8n_workflow(prompt)`: Triggers a remote n8n workflow via webhook, sending a prompt and returning the response.

### 📚 Resources

Resources provide context and data to the AI model.

- `calculator://support-playbook`: Reads and returns the content of the "Customer Support Playbook" (`resource_exampe.md`).

### 📝 Prompts

Prompts provide structured templates for the AI model to generate content.

- `webinar_blog_post`: A template to convert a webinar transcript into an engaging blog post. requires: `webinar_title`, `webinar_date`, `speakers`, `transcript`.

## Prerequisites

- **Python 3.10+** (Recommend managing with `uv`)
- **[uv](https://github.com/astral-sh/uv)**: A fast Python package installer and resolver.
- **npx**: Required if you want to use the MCP Inspector for testing.

## Installation & Setup

1.  **Clone or Navigate to the Project Directory**

2.  **Install Dependencies**
    Use `uv` to sync the project dependencies:

    ```bash
    uv sync
    ```

3.  **Configure Environment Variables**
    This server requires environment variables for the n8n integration.

    Create a `.env` file from the example:

    ```bash
    cp .env.example .env
    ```

    Open `.env` and configure your settings:

    ```env
    N8N_WEBHOOK_URL=https://your-n8n-instance.com/webhook/...
    N8N_HEADER_NAME=Your-Header-Name
    N8N_HEADER_VALUE=Your-Header-Value
    ```

    _Note: If `N8N_HEADER_NAME` and `N8N_HEADER_VALUE` are set, they will be included in the webhook request headers._

## Usage

### 🔍 Testing with MCP Inspector

The MCP Inspector is a developer tool to test your server's tools, resources, and prompts in a web interface.

Run the follow command:

```bash
npx @modelcontextprotocol/inspector uv run server.py
```

This will launch a local server (usually at `http://localhost:5173`) where you can interact with your MCP server.

### 🤖 Integration with Claude for Desktop

To use this server with the Claude desktop app:

1.  **Locate Configuration File:**
    - macOS: `~/Library/Application Support/Claude/claude_desktop_config.json`
    - Windows: `%APPDATA%\Claude\claude_desktop_config.json`

2.  **Update Configuration:**
    Add the server configuration to the `mcpServers` object. You can copy the contents of the `claude_desktop_config.json` file provided in this repository.

    ```json
    {
      "mcpServers": {
        "calculator": {
          "command": "uv",
          "args": ["--directory", "/ABSOLUTE/PATH/TO/THIS/PROJECT", "run", "server.py"]
        }
      }
    }
    ```

    **Important:** Replace `/ABSOLUTE/PATH/TO/THIS/PROJECT` with the actual absolute path to this directory on your machine.

3.  **Restart Claude:**
    Restart the Claude application to load the new server.

## Troubleshooting

- **Timeout Errors:** The n8n workflow trigger has a 30-second timeout. If your workflow takes longer, you may need to increase this in `server.py`.
- **Missing Environment Variables:** Ensure your `.env` file is properly set up and that you are running the server from the project root where the `.env` file is located.
- **Claude Connection Issues:** Check Claude's logs for connection details. Ensure the absolute path in the config file is correct.

## Project Structure

- `server.py`: Main MCP server implementation.
- `resource_exampe.md`: Source file for the support playbook resource.
- `prompt.md`: Template file for the blog post prompt.
- `.env`: (Ignored by git) Local configuration for secrets.
- `pyproject.toml`: Python project and dependency definition.