MCP (Model Context Protocol) Integration¶

The struct tool now supports MCP (Model Context Protocol) integration, providing a programmable interface to interact with structure definitions. This enables automation and integration with other tools, particularly AI-assisted development workflows.

Available MCP Tools¶

1. list_structures¶

Lists all available structure definitions.

{
  "name": "list_structures",
  "arguments": {
    "structures_path": "/path/to/custom/structures"  // optional
  }
}

Parameters: - structures_path (optional): Custom path to structure definitions

2. get_structure_info¶

Get detailed information about a specific structure.

{
  "name": "get_structure_info",
  "arguments": {
    "structure_name": "project/python",
    "structures_path": "/path/to/custom/structures"  // optional
  }
}

Parameters: - structure_name (required): Name of the structure to get info about - structures_path (optional): Custom path to structure definitions

3. generate_structure¶

Generate a project structure using specified definition and options.

{
  "name": "generate_structure",
  "arguments": {
    "structure_definition": "project/python",
    "base_path": "/tmp/myproject",
    "output": "console",  // "console" or "files"
    "dry_run": false,
    "mappings": {
      "project_name": "MyProject",
      "author": "John Doe"
    },
    "structures_path": "/path/to/custom/structures"  // optional
  }
}

Parameters: - structure_definition (required): Name or path to the structure definition - base_path (required): Base path where the structure should be generated - output (optional): Output mode - "console" for stdout or "files" for actual generation (default: "files") - dry_run (optional): Perform a dry run without creating actual files (default: false) - mappings (optional): Variable mappings for template substitution - structures_path (optional): Custom path to structure definitions

4. validate_structure¶

Validate a structure configuration YAML file.

{
  "name": "validate_structure",
  "arguments": {
    "yaml_file": "/path/to/structure.yaml"
  }
}

Parameters: - yaml_file (required): Path to the YAML configuration file to validate

Usage¶

Starting the MCP Server (FastMCP stdio / http / sse)¶

The MCP server uses FastMCP (v2.0+) and can run over stdio, http, or sse transports.

stdio (default):
```
struct mcp --server --transport stdio
```

HTTP (StreamableHTTP):

struct mcp --server --transport http --host 127.0.0.1 --port 9000 --path /mcp

SSE:

struct mcp --server --transport sse --host 0.0.0.0 --port 8080 --path /events

Command Line Integration¶

The existing list and info commands now support an optional --mcp flag:

# List structures with MCP support
struct list --mcp

# Get structure info with MCP support
struct info project/python --mcp

MCP Client Integration¶

Claude Desktop Integration¶

Add the following to your Claude Desktop configuration file:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json Windows: %APPDATA%\Claude\claude_desktop_config.json Linux: ~/.config/claude/claude_desktop_config.json

{
  "mcpServers": {
    "struct": {
      "command": "struct",
      "args": ["mcp", "--server"],
      "cwd": "/path/to/your/project"
    }
  }
}

Cline/Continue Integration¶

For Cline (VS Code extension), add to your .cline_mcp_settings.json:

{
  "mcpServers": {
    "struct": {
      "command": "struct",
      "args": ["mcp", "--server"]
    }
  }
}

Custom MCP Client Integration¶

For any MCP-compatible client, connect over stdio with your preferred SDK:

// Node.js example (MCP JS SDK)
import { StdioClientTransport } from '@modelcontextprotocol/sdk/client/stdio.js';
import { Client } from '@modelcontextprotocol/sdk/client/index.js';

const transport = new StdioClientTransport({
  command: 'struct',
  args: ['mcp', '--server']
});

const client = new Client(
  {
    name: "struct-client",
    version: "1.0.0"
  },
  {
    capabilities: {}
  }
);

await client.connect(transport);

# Python example (MCP Python SDK)
import asyncio
from mcp import ClientSession, StdioServerParameters
from mcp.client.stdio import stdio_client

async def main():
    server_params = StdioServerParameters(
        command="struct",
        args=["mcp", "--server"]
    )

    async with stdio_client(server_params) as (read, write):
        async with ClientSession(read, write) as session:
            await session.initialize()

            tools = await session.list_tools()
            print([t.name for t in tools.tools])

            result = await session.call_tool("list_structures", {})
            # FastMCP tools return plain text content
            print(result.content[0].text)

if __name__ == "__main__":
    asyncio.run(main())

AI-Assisted Development Workflows¶

The MCP integration is particularly powerful for AI-assisted development workflows:

Console Output Mode¶

Using output: "console" with generate_structure allows piping structure content to stdout for subsequent AI prompts:

# Generate structure content to console for AI review
struct mcp --server | ai-tool "Review this project structure"

Chaining Operations¶

The MCP tools can be chained together for complex workflows:

List available structures
Get detailed info about a specific structure
Generate the structure with custom mappings
Validate any custom configurations

Integration Examples¶

Example 1: Generate and Review

// 1. Generate structure to console
{
  "name": "generate_structure",
  "arguments": {
    "structure_definition": "project/python",
    "base_path": "/tmp/review",
    "output": "console"
  }
}

// 2. Use output as context for AI code review

Example 2: Custom Structure Validation

// 1. Validate custom structure
{
  "name": "validate_structure",
  "arguments": {
    "yaml_file": "/path/to/custom-structure.yaml"
  }
}

// 2. If valid, generate using the custom structure
{
  "name": "generate_structure",
  "arguments": {
    "structure_definition": "file:///path/to/custom-structure.yaml",
    "base_path": "/tmp/project"
  }
}

Configuration¶

Environment Variables¶

The MCP server respects the same environment variables as the regular struct tool: - STRUCT_STRUCTURES_PATH: Default path for structure definitions - Any mapping variables used in templates

Client Configuration Examples¶

1. Basic Configuration¶

{
  "command": "struct",
  "args": ["mcp", "--server"]
}

2. With Custom Structures Path¶

{
  "command": "struct",
  "args": ["mcp", "--server"],
  "env": {
    "STRUCT_STRUCTURES_PATH": "/path/to/custom/structures"
  }
}

3. With Python Virtual Environment¶

{
  "command": "/path/to/venv/bin/python",
  "args": ["-m", "struct_module.main", "mcp", "--server"],
  "cwd": "/path/to/struct/project"
}

4. Using Shell Script Wrapper¶

Create a shell script struct-mcp.sh:

#!/bin/bash
cd /path/to/your/project
source .venv/bin/activate
struct mcp --server

Then configure your MCP client:

{
  "command": "/path/to/struct-mcp.sh",
  "args": []
}

Quick Start Guide¶

Step 1: Install struct with MCP support¶

pip install fastmcp>=2.0
# (your MCP client may also require installing the MCP SDK, e.g., `pip install mcp`)

Step 2: Test MCP server¶

# Test that MCP server starts correctly
struct mcp --server
# Should show: Starting MCP server...
# Press Ctrl+C to stop

Step 3: Configure your MCP client¶

Add the configuration to your MCP client (see examples above).

Step 4: Start using MCP tools¶

Once connected, you can use these tools: - list_structures - Get all available structures - get_structure_info - Get details about a specific structure - generate_structure - Generate project structures - validate_structure - Validate YAML configuration files

Troubleshooting¶

Common Issues¶

"Command not found: struct"
Solution: Ensure struct is installed and in your PATH
Alternative: Use full path to Python executable
MCP server won't start
Check if mcp package is installed: pip show mcp
Try running with verbose logging: struct mcp --server --log DEBUG
Client can't connect
Verify the command and args in your client configuration
Test MCP server manually first
Check working directory and environment variables
Structures not found
Set STRUCT_STRUCTURES_PATH environment variable
Use absolute paths in configuration
Verify structure files exist and are readable

Debug Mode¶

# Run with debug logging
STRUCT_LOG_LEVEL=DEBUG struct mcp --server

Benefits¶

Automation: Programmatic access to all struct tool functionality
Integration: Easy integration with other development tools
AI Workflows: Enhanced support for AI-assisted development processes
Consistency: Same underlying logic as CLI commands
Flexibility: Support for custom paths, mappings, and output modes

Backward Compatibility¶

All existing struct tool functionality remains unchanged. The MCP integration is additive and does not affect existing workflows or commands.