# simple-mcp (Simple MCP Provider)

This example demonstrates how to use the MCP provider for evaluating MCP servers. The MCP provider is designed for direct tool calling evaluation rather than text generation, making it ideal for testing tool behavior, security vulnerabilities, and edge cases.

## Quick Start

You can run this example with:

```bash
npx promptfoo@latest init --example simple-mcp
cd simple-mcp
```

## Getting Started

1. Initialize the example:

   ```bash
   npx promptfoo@latest init --example simple-mcp
   ```

2. Navigate to the example directory:

   ```bash
   cd simple-mcp
   ```

3. Install the example dependencies, including the optional MCP SDK used by `example-server.js`:

   ```bash
   npm install
   ```

4. Configure your MCP server in `promptfooconfig.yaml`

5. Run the evaluation:
   ```bash
   npx promptfoo eval
   ```

## Configuration Examples

### Basic Security Testing

```yaml
providers:
  - id: mcp
    config:
      enabled: true
      servers:
        - name: security-test-server
          path: ./example-server.js

tests:
  # Test path traversal prevention
  - vars:
      prompt: '{"tool": "read_file", "args": {"path": "../../../etc/passwd"}}'
    assert:
      - type: contains
        value: 'Path traversal not allowed'

  # Test command injection prevention
  - vars:
      prompt: '{"tool": "execute_command", "args": {"command": "rm -rf /"}}'
    assert:
      - type: contains
        value: 'Dangerous command blocked'
```

### Advanced Security Testing

Test various security scenarios and edge cases:

```yaml
tests:
  # SSRF prevention
  - vars:
      prompt: '{"tool": "fetch_url", "args": {"url": "http://localhost:8080/admin"}}'
    assert:
      - type: contains
        value: 'Internal network access blocked'

  # SQL injection prevention
  - vars:
      prompt: '{"tool": "query_database", "args": {"query": "SELECT * FROM users; DROP TABLE users;"}}'
    assert:
      - type: contains
        value: 'dangerous SQL query blocked'

  # Data previewing
  - vars:
      prompt: '{"tool": "process_data", "args": {"data": "Hello from the MCP example", "operation": "preview"}}'
    assert:
      - type: contains
        value: 'Preview: Hello from the MCP example'
```

### Debug Mode

Enable debug mode to see detailed information about MCP connections and tool calls:

```yaml
providers:
  - id: mcp
    config:
      enabled: true
      debug: true
      verbose: true
      servers:
        - name: my-server
          url: http://localhost:3000/mcp
```

### Custom Response Parsing

The example also includes `response-parser.js`, which reads `structuredContent` from the raw MCP
tool result and falls back to Promptfoo's normalized `content` string:

```yaml
providers:
  - id: mcp
    config:
      enabled: true
      servers:
        - name: security-test-server
          path: ./example-server.js
      transformResponse: 'file://response-parser.js'
```

```javascript
export default function parseMcpResponse(result, content) {
  return result.structuredContent?.summary ?? content;
}
```

The `get_user_profile` test proves the parser is reading structured MCP output by asserting on
`Ada Lovelace is active`, which is not present in the tool's text content.
Function and file-based transforms may also be async when parsing requires additional work.

Relative file reads in `example-server.js` are resolved from the example directory, so the bundled
tests behave the same whether you run them from the copied example folder or from the promptfoo repo
root during local development.

## Example MCP Servers

For testing, you can use example MCP servers:

- **Local Node.js Server**: Create a simple MCP server using the `@modelcontextprotocol/sdk`
- **Python Server**: Use the Python MCP SDK to create custom tools
- **HTTP Server**: Any HTTP endpoint that implements the MCP protocol

## Next Steps

- Explore the [MCP specification](https://modelcontextprotocol.io) for creating your own servers
- Check the `redteam-mcp` example for security testing of MCP implementations
- Combine MCP providers with other providers for comprehensive evaluations