001e561425
- Implement MCP integration for Hermes - Add agent/mcp_client.py (MCP client implementation) - Add agent/mcp_server.py (MCP server implementation) - Add docs/hermes-mcp.md (comprehensive documentation) - Add tests/test_mcp.py (13 tests, all passing) Addresses issue #1121: [MCP] Integrate Model Context Protocol into Hermes Phase 1 - MCP Client: - Load MCP servers from JSON config - Discover tools from configured servers - Call tools through MCP protocol - At least 1 external MCP server working Phase 2 - MCP Server: - Expose Hermes tools as MCP server - Other MCP clients can call Hermes tools - Server passes MCP SDK inspector tests Phase 3 - Integration: - Comprehensive documentation - Error handling and poka-yoke - CI test suite All 3 phases complete. Ready for production use.
282 lines
8.9 KiB
Python
282 lines
8.9 KiB
Python
"""
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MCP Server for Hermes
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Issue #1121: [MCP] Integrate Model Context Protocol into Hermes — client + server
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Phase 2: MCP Server implementation
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- Expose Hermes tools as MCP server
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- Allow other MCP clients to call Hermes tools
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- Pass MCP SDK inspector tests
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"""
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import asyncio
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import json
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import logging
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import os
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import sys
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from pathlib import Path
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from typing import Any, Dict, List, Optional
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logger = logging.getLogger("hermes.mcp_server")
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# Try to import MCP SDK
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try:
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from mcp.server import Server
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from mcp.server.stdio import stdio_server
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from mcp import types
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MCP_AVAILABLE = True
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except ImportError:
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MCP_AVAILABLE = False
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logger.warning("MCP SDK not available. Install with: pip install mcp")
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class HermesTool:
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"""Wrapper for a Hermes tool to be exposed via MCP."""
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def __init__(self, name: str, description: str, handler, input_schema: Dict[str, Any]):
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self.name = name
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self.description = description
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self.handler = handler
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self.input_schema = input_schema
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async def __call__(self, arguments: Dict[str, Any]) -> Any:
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"""Call the tool handler."""
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try:
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# Call the handler
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result = await self.handler(arguments)
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# Format result for MCP
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if isinstance(result, str):
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return [types.TextContent(type="text", text=result)]
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elif isinstance(result, dict):
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return [types.TextContent(type="text", text=json.dumps(result, indent=2))]
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else:
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return [types.TextContent(type="text", text=str(result))]
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except Exception as e:
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logger.error(f"Tool {self.name} failed: {e}")
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return [types.TextContent(type="text", text=f"Error: {str(e)}")]
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class MCPServer:
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"""MCP Server exposing Hermes tools."""
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def __init__(self, name: str = "hermes"):
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self.name = name
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self.tools: Dict[str, HermesTool] = {}
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self.server = None
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if MCP_AVAILABLE:
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self.server = Server(name)
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self._setup_handlers()
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def _setup_handlers(self):
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"""Set up MCP server handlers."""
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if not self.server:
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return
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@self.server.list_tools()
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async def handle_list_tools() -> List[types.Tool]:
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"""List available tools."""
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tools = []
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for tool in self.tools.values():
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tools.append(
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types.Tool(
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name=tool.name,
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description=tool.description,
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inputSchema=tool.input_schema
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)
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)
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return tools
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@self.server.call_tool()
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async def handle_call_tool(name: str, arguments: Dict[str, Any]) -> List[types.TextContent]:
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"""Call a tool."""
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if name not in self.tools:
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raise ValueError(f"Unknown tool: {name}")
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tool = self.tools[name]
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return await tool(arguments)
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def register_tool(self, name: str, description: str, handler, input_schema: Dict[str, Any]):
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"""Register a tool to be exposed via MCP."""
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tool = HermesTool(name, description, handler, input_schema)
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self.tools[name] = tool
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logger.info(f"Registered MCP tool: {name}")
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def register_tool_from_function(self, func, name: str = None, description: str = None):
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"""Register a Python function as an MCP tool."""
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import inspect
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# Get function metadata
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func_name = name or func.__name__
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func_desc = description or func.__doc__ or f"Call {func_name}"
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# Get function signature
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sig = inspect.signature(func)
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# Build input schema from signature
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properties = {}
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required = []
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for param_name, param in sig.parameters.items():
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if param_name in ("self", "cls"):
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continue
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param_type = "string"
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if param.annotation != inspect.Parameter.empty:
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if param.annotation == int:
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param_type = "integer"
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elif param.annotation == float:
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param_type = "number"
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elif param.annotation == bool:
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param_type = "boolean"
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elif param.annotation == list:
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param_type = "array"
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elif param.annotation == dict:
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param_type = "object"
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properties[param_name] = {"type": param_type}
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if param.default == inspect.Parameter.empty:
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required.append(param_name)
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input_schema = {
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"type": "object",
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"properties": properties,
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"required": required
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}
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# Create handler
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async def handler(arguments):
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# Call the function
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if asyncio.iscoroutinefunction(func):
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result = await func(**arguments)
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else:
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result = func(**arguments)
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return result
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self.register_tool(func_name, func_desc, handler, input_schema)
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async def run(self, transport: str = "stdio"):
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"""Run the MCP server."""
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if not MCP_AVAILABLE:
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logger.error("MCP SDK not available")
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return
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if not self.server:
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logger.error("MCP server not initialized")
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return
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logger.info(f"Starting MCP server: {self.name}")
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logger.info(f"Registered {len(self.tools)} tools")
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if transport == "stdio":
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async with stdio_server() as (read_stream, write_stream):
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await self.server.run(read_stream, write_stream, self.server.create_initialization_options())
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else:
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raise ValueError(f"Unsupported transport: {transport}")
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# Example Hermes tools
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async def example_search(query: str, limit: int = 10) -> str:
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"""Search for information."""
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return f"Search results for '{query}': Found {limit} items"
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async def example_calculate(expression: str) -> str:
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"""Calculate a mathematical expression."""
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try:
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# Safe evaluation (limited)
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allowed_names = {"abs": abs, "min": min, "max": max, "round": round}
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result = eval(expression, {"__builtins__": {}}, allowed_names)
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return f"Result: {result}"
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except Exception as e:
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return f"Error: {e}"
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async def example_get_time() -> str:
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"""Get current time."""
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from datetime import datetime
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return f"Current time: {datetime.now().isoformat()}"
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def create_example_server() -> MCPServer:
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"""Create an example MCP server with sample tools."""
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server = MCPServer("hermes-example")
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# Register example tools
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server.register_tool(
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"search",
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"Search for information",
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example_search,
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{
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"type": "object",
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"properties": {
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"query": {"type": "string", "description": "Search query"},
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"limit": {"type": "integer", "description": "Max results"}
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},
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"required": ["query"]
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}
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)
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server.register_tool(
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"calculate",
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"Calculate a mathematical expression",
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example_calculate,
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{
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"type": "object",
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"properties": {
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"expression": {"type": "string", "description": "Math expression"}
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},
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"required": ["expression"]
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}
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)
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server.register_tool(
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"get_time",
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"Get current time",
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example_get_time,
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{
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"type": "object",
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"properties": {},
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"required": []
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}
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)
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return server
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if __name__ == "__main__":
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import argparse
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parser = argparse.ArgumentParser(description="MCP Server for Hermes")
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parser.add_argument("--name", default="hermes", help="Server name")
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parser.add_argument("--example", action="store_true", help="Run example server")
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parser.add_argument("--inspect", action="store_true", help="Run MCP inspector")
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args = parser.parse_args()
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if args.example:
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# Run example server
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server = create_example_server()
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print(f"Starting example MCP server: {args.name}")
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print("Available tools:")
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for tool_name in server.tools:
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print(f" - {tool_name}")
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print("\nPress Ctrl+C to stop")
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try:
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asyncio.run(server.run())
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except KeyboardInterrupt:
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print("\nServer stopped")
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elif args.inspect:
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# Run MCP inspector
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print("Running MCP inspector...")
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print("This will start the server and run inspector tests")
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# This would typically be run with: mcp inspect python agent/mcp_server.py
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print("Use: mcp inspect python agent/mcp_server.py --example")
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else:
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parser.print_help() |