#!/usr/bin/env python3
"""
Example demonstrating MCP logging middleware functionality.
This script shows how the MCPLoggingMiddleware logs:
- Tool call parameters at INFO level
- Tool responses at INFO level
- Execution timing
- Error handling
The logs use "CLIENT_MCP" prefix for easy filtering.
"""
import asyncio
import logging
from unittest.mock import AsyncMock, MagicMock
from playwright_proxy_mcp.middleware.mcp_logging import MCPLoggingMiddleware
# Configure logging to see INFO level messages
logging.basicConfig(
level=logging.INFO,
format="%(asctime)s - %(name)s - %(levelname)s - %(message)s",
)
async def main():
"""Demonstrate logging middleware functionality"""
print("=" * 80)
print("MCP Logging Middleware Demonstration")
print("=" * 80)
print()
# Create middleware with full logging enabled
middleware = MCPLoggingMiddleware(
log_request_params=True, log_response_data=True, max_log_length=10000
)
print("1. Creating mock context for browser_navigate tool call...")
print()
# Create mock context
mock_context = MagicMock()
mock_context.message = MagicMock()
mock_context.message.name = "browser_navigate"
mock_context.message.arguments = {
"url": "https://example.com",
"silent_mode": False,
"jmespath_query": '[?role == "button"]',
"output_format": "json",
"limit": 50,
}
# Create mock response
mock_response = {
"success": True,
"url": "https://example.com",
"cache_key": "nav_abc123",
"total_items": 150,
"offset": 0,
"limit": 50,
"has_more": True,
"snapshot": '{"elements": [...]}',
"error": None,
"output_format": "json",
}
# Mock call_next function
mock_call_next = AsyncMock(return_value=mock_response)
print("2. Calling middleware.on_call_tool()...")
print()
print("Expected logs:")
print(" - CLIENT_MCP → Tool call: browser_navigate")
print(" - CLIENT_MCP Tool 'browser_navigate' arguments: {...}")
print(" - CLIENT_MCP ← Tool result: browser_navigate (Xms)")
print(" - CLIENT_MCP Tool 'browser_navigate' result: {...}")
print()
print("Actual logs:")
print("-" * 80)
# Execute the middleware
result = await middleware.on_call_tool(mock_context, mock_call_next)
print("-" * 80)
print()
print(f"3. Result returned: {result}")
print()
print("=" * 80)
print("Demonstration Complete!")
print()
print("Key Features:")
print(" ✓ Request parameters logged at INFO level")
print(" ✓ Response data logged at INFO level")
print(" ✓ Execution timing included")
print(" ✓ Data truncated at 10000 chars (configurable)")
print(" ✓ Easy filtering with 'CLIENT_MCP' prefix")
print()
print("Log Filtering Examples:")
print(" # All client MCP calls")
print(" grep 'CLIENT_MCP' logs/playwright-proxy-mcp.log")
print()
print(" # Specific tool calls")
print(" grep 'CLIENT_MCP.*browser_navigate' logs/playwright-proxy-mcp.log")
print()
print(" # Only errors")
print(" grep 'CLIENT_MCP ✗' logs/playwright-proxy-mcp.log")
print("=" * 80)
if __name__ == "__main__":
asyncio.run(main())
