Drop Python files, get MCP tools instantly.
A dynamic MCP server that automatically discovers Python files in a directory and exposes them as tools to any MCP-compatible AI client. Created through collaboration between Ben Wilson and Claude (Anthropic).
How it works
# 1. Write a Python file or have the LLM write one
def invoke(arguments):
"""Generate a secure password
Parameters:
- length: Length of password (default: 12)
- include_symbols: Include special characters (default: true)
"""
import random, string
length = int(arguments.get('length', 12))
chars = string.ascii_letters + string.digits
if arguments.get('include_symbols', 'true').lower() == 'true':
chars += "!@#$%^&*"
return ''.join(random.choice(chars) for _ in range(length))
# 2. Save it to your tools directory
echo "# Above code" > tools/password_generator.py
# 3. AI can now use it immediately (after restart in Claude Desktop)
🤖 "Generate a 16-character password with symbols"
🔧 Tool: password_generator(length="16", include_symbols="true")
📤 Result: "K9#mP2$vR8@nQ3!x"
Quick Start
1. Clone and Setup
git clone https://github.com/your-username/mcp-dynamic-tools
cd mcp-dynamic-tools
Claude Desktop (~/.config/claude_desktop_config.json):
{
"mcpServers": {
"mcp-dynamic-tools": {
"command": "python3",
"args": [
"/path/to/mcp-dynamic-tools/src/mcp_dynamic_tools/server.py",
"--tools-dir",
"/path/to/tools"
]
}
}
}
# tools/hello.py
def invoke(arguments):
"""Say hello to someone
Parameters:
- name: The person to greet
"""
name = arguments.get('name', 'World')
return f"Hello, {name}! 👋"
5. Restart Your MCP Client
Your hello tool is now available to any AI using your MCP client!
How It Works
- File Discovery: Server monitors your tools directory
- Code Analysis: Validates Python files have
invoke(arguments) function - Schema Extraction: Parses docstrings for parameter definitions
- MCP Integration: Exposes tools via standard MCP protocol
- Error Handling: Provides detailed feedback for debugging
Function Signature
Every tool must have this exact signature:
def invoke(arguments):
# Your tool logic here
return result
def invoke(arguments):
"""Brief description of what the tool does
Parameters:
- param_name: Description of the parameter
- another_param: Description with (default: value)
"""
Text Processor:
def invoke(arguments):
"""Transform text in various ways
Parameters:
- text: The text to transform
- operation: Type of transformation (uppercase, lowercase, reverse)
"""
text = arguments.get('text', '')
operation = arguments.get('operation', 'uppercase')
if operation == 'uppercase':
return text.upper()
elif operation == 'lowercase':
return text.lower()
elif operation == 'reverse':
return text[::-1]
else:
return f"Unknown operation: {operation}"
API Caller:
def invoke(arguments):
"""Fetch data from a REST API
Parameters:
- url: The API endpoint to call
- method: HTTP method (default: GET)
"""
import urllib.request
import json
url = arguments.get('url')
method = arguments.get('method', 'GET')
if not url:
return "Error: URL is required"
try:
with urllib.request.urlopen(url) as response:
return json.loads(response.read())
except Exception as e:
return f"Error: {str(e)}"
Robust Error Handling
The server provides detailed error messages to help you debug:
- Syntax Errors: Shows line numbers and specific issues
- Import Errors: Reports missing dependencies
- Function Signature: Validates
invoke(arguments) signature - Runtime Errors: Captures and reports execution problems
Known Limitations
Claude Desktop 0.9.2
Claude Desktop currently doesn't support dynamic tool discovery (see discussion). This means:
- ✅ Tools work perfectly once discovered
- ❌ Restart required when adding new tools
- 🔄 Future support planned - our server is ready with
listChanged: true
Workaround: Restart Claude Desktop after adding new tools.
Tools appear with server prefix: local__mcp-dynamic-tools__your_tool_name
Contributing
This project was created through human-AI collaboration. We welcome contributions!
- Fork the repository
- Create your feature branch
- Add tests for new functionality
- Submit a pull request
License
MIT License - see LICENSE file for details.
Acknowledgments
- Ben Vierck - Architecture and development
- Claude (Anthropic) - Co-development and testing
- MCP Community - Protocol development and feedback