mirror of
https://github.com/zhayujie/chatgpt-on-wechat.git
synced 2026-06-02 09:48:22 +08:00
b2429ec30c
Allows CowAgent to dynamically load tools from any MCP server at startup,
extending the agent from a fixed toolset to an open, extensible tool ecosystem.
## What's added
- `agent/tools/mcp/mcp_client.py`: lightweight JSON-RPC client supporting both
stdio (subprocess) and SSE (HTTP) transports — zero extra dependencies
- `agent/tools/mcp/mcp_tool.py`: `McpTool` wraps a single MCP tool as a
`BaseTool`, with dynamic name/description/params set at instance level
- `agent/tools/tool_manager.py`: new `_load_mcp_tools()` loads MCP servers at
startup via `McpClientRegistry`; falls back gracefully on any error; no-op
when `mcp_servers` is not configured
- `config.py`: registers `mcp_servers` in `available_setting` with inline docs
## Design
- No new dependencies — JSON-RPC implemented from scratch using stdlib only
- MCP clients are long-lived (initialized once, shared across tool calls)
- `McpClientRegistry` holds all subprocess handles and shuts them down cleanly
- Server init failures are non-fatal: logged as warnings, agent continues normally
- Zero overhead when `mcp_servers` is absent from config
## Config example
```json
"mcp_servers": [
{
"name": "filesystem",
"type": "stdio",
"command": "npx",
"args": ["-y", "@modelcontextprotocol/server-filesystem", "/tmp"]
}
]
```
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
308 lines
14 KiB
Python
308 lines
14 KiB
Python
import importlib
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import importlib.util
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from pathlib import Path
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from typing import Dict, Any, Type
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from agent.tools.base_tool import BaseTool
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from common.log import logger
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from config import conf
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class ToolManager:
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"""
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Tool manager for managing tools.
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"""
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_instance = None
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def __new__(cls):
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"""Singleton pattern to ensure only one instance of ToolManager exists."""
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if cls._instance is None:
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cls._instance = super(ToolManager, cls).__new__(cls)
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cls._instance.tool_classes = {} # Store tool classes instead of instances
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cls._instance._initialized = False
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return cls._instance
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def __init__(self):
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# Initialize only once
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if not hasattr(self, 'tool_classes'):
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self.tool_classes = {} # Dictionary to store tool classes
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if not hasattr(self, '_mcp_registry'):
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self._mcp_registry = None # 懒初始化，有配置时才创建
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if not hasattr(self, '_mcp_tool_instances'):
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self._mcp_tool_instances: dict = {} # tool_name -> McpTool instance
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def load_tools(self, tools_dir: str = "", config_dict=None):
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"""
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Load tools from both directory and configuration.
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:param tools_dir: Directory to scan for tool modules
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"""
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if tools_dir:
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self._load_tools_from_directory(tools_dir)
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self._configure_tools_from_config()
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else:
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self._load_tools_from_init()
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self._configure_tools_from_config(config_dict)
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self._load_mcp_tools()
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def _load_tools_from_init(self) -> bool:
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"""
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Load tool classes from tools.__init__.__all__
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:return: True if tools were loaded, False otherwise
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"""
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try:
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# Try to import the tools package
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tools_package = importlib.import_module("agent.tools")
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# Check if __all__ is defined
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if hasattr(tools_package, "__all__"):
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tool_classes = tools_package.__all__
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# Import each tool class directly from the tools package
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for class_name in tool_classes:
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try:
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# Skip base classes
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if class_name in ["BaseTool", "ToolManager"]:
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continue
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# Get the class directly from the tools package
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if hasattr(tools_package, class_name):
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cls = getattr(tools_package, class_name)
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if (
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isinstance(cls, type)
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and issubclass(cls, BaseTool)
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and cls != BaseTool
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):
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try:
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# Skip tools that need special initialization
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if class_name in ["MemorySearchTool", "MemoryGetTool"]:
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logger.debug(f"Skipped tool {class_name} (requires memory_manager)")
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continue
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# McpTool instances are registered dynamically via _load_mcp_tools()
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if class_name == "McpTool":
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logger.debug(f"Skipped tool {class_name} (registered dynamically via mcp_servers config)")
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continue
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# Create a temporary instance to get the name
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temp_instance = cls()
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tool_name = temp_instance.name
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# Store the class, not the instance
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self.tool_classes[tool_name] = cls
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logger.debug(f"Loaded tool: {tool_name} from class {class_name}")
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except ImportError as e:
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# Handle missing dependencies with helpful messages
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error_msg = str(e)
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if "playwright" in error_msg:
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logger.warning(
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f"[ToolManager] Browser tool not loaded - missing dependencies.\n"
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f" To enable browser tool, run:\n"
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f" pip install playwright\n"
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f" playwright install chromium"
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)
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elif "markdownify" in error_msg:
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logger.warning(
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f"[ToolManager] {cls.__name__} not loaded - missing markdownify.\n"
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f" Install with: pip install markdownify"
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)
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else:
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logger.warning(f"[ToolManager] {cls.__name__} not loaded due to missing dependency: {error_msg}")
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except Exception as e:
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logger.error(f"Error initializing tool class {cls.__name__}: {e}")
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except Exception as e:
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logger.error(f"Error importing class {class_name}: {e}")
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return len(self.tool_classes) > 0
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return False
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except ImportError:
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logger.warning("Could not import agent.tools package")
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return False
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except Exception as e:
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logger.error(f"Error loading tools from __init__.__all__: {e}")
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return False
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def _load_tools_from_directory(self, tools_dir: str):
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"""Dynamically load tool classes from directory"""
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tools_path = Path(tools_dir)
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# Traverse all .py files
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for py_file in tools_path.rglob("*.py"):
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# Skip initialization files and base tool files
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if py_file.name in ["__init__.py", "base_tool.py", "tool_manager.py"]:
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continue
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# Get module name
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module_name = py_file.stem
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try:
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# Load module directly from file
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spec = importlib.util.spec_from_file_location(module_name, py_file)
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if spec and spec.loader:
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module = importlib.util.module_from_spec(spec)
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spec.loader.exec_module(module)
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# Find tool classes in the module
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for attr_name in dir(module):
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cls = getattr(module, attr_name)
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if (
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isinstance(cls, type)
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and issubclass(cls, BaseTool)
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and cls != BaseTool
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):
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try:
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# Skip memory tools (they need special initialization with memory_manager)
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if attr_name in ["MemorySearchTool", "MemoryGetTool"]:
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logger.debug(f"Skipped tool {attr_name} (requires memory_manager)")
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continue
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# Create a temporary instance to get the name
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temp_instance = cls()
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tool_name = temp_instance.name
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# Store the class, not the instance
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self.tool_classes[tool_name] = cls
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except ImportError as e:
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# Handle missing dependencies with helpful messages
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error_msg = str(e)
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if "playwright" in error_msg:
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logger.warning(
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f"[ToolManager] Browser tool not loaded - missing dependencies.\n"
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f" To enable browser tool, run:\n"
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f" pip install playwright\n"
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f" playwright install chromium"
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)
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elif "markdownify" in error_msg:
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logger.warning(
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f"[ToolManager] {cls.__name__} not loaded - missing markdownify.\n"
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f" Install with: pip install markdownify"
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)
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else:
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logger.warning(f"[ToolManager] {cls.__name__} not loaded due to missing dependency: {error_msg}")
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except Exception as e:
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logger.error(f"Error initializing tool class {cls.__name__}: {e}")
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except Exception as e:
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print(f"Error importing module {py_file}: {e}")
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def _configure_tools_from_config(self, config_dict=None):
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"""Configure tool classes based on configuration file"""
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try:
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# Get tools configuration
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tools_config = config_dict or conf().get("tools", {})
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# Record tools that are configured but not loaded
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missing_tools = []
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# Store configurations for later use when instantiating
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self.tool_configs = tools_config
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# Check which configured tools are missing
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for tool_name in tools_config:
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if tool_name not in self.tool_classes:
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missing_tools.append(tool_name)
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# If there are missing tools, record warnings
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if missing_tools:
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for tool_name in missing_tools:
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if tool_name == "browser":
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logger.warning(
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f"[ToolManager] Browser tool is configured but not loaded.\n"
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f" To enable browser tool, run:\n"
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f" pip install playwright\n"
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f" playwright install chromium"
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)
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elif tool_name == "google_search":
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logger.warning(
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f"[ToolManager] Google Search tool is configured but may need API key.\n"
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f" Get API key from: https://serper.dev\n"
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f" Configure in config.json: tools.google_search.api_key"
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)
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else:
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logger.warning(f"[ToolManager] Tool '{tool_name}' is configured but could not be loaded.")
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except Exception as e:
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logger.error(f"Error configuring tools from config: {e}")
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def _load_mcp_tools(self):
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"""Load MCP tools from mcp_servers config. Failures are non-fatal."""
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try:
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mcp_servers_config = conf().get("mcp_servers", [])
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if not mcp_servers_config:
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return
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from agent.tools.mcp.mcp_client import McpClientRegistry
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from agent.tools.mcp.mcp_tool import McpTool
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self._mcp_registry = McpClientRegistry()
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self._mcp_registry.start_all(mcp_servers_config)
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for server_name, client in self._mcp_registry.all_clients().items():
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try:
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tool_schemas = client.list_tools()
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for schema in tool_schemas:
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tool_name = schema.get("name", "")
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if not tool_name:
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continue
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mcp_tool = McpTool(client, schema, server_name)
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self._mcp_tool_instances[tool_name] = mcp_tool
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logger.debug(f"[ToolManager] Loaded MCP tool: {tool_name} from server '{server_name}'")
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except Exception as e:
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logger.warning(f"[ToolManager] Failed to list tools from MCP server '{server_name}': {e}")
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logger.info(f"[ToolManager] Loaded {len(self._mcp_tool_instances)} MCP tool(s) in total")
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except Exception as e:
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logger.warning(f"[ToolManager] MCP tool loading failed, skipping: {e}")
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def create_tool(self, name: str) -> BaseTool:
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"""
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Get a new instance of a tool by name.
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:param name: The name of the tool to get.
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:return: A new instance of the tool or None if not found.
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"""
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tool_class = self.tool_classes.get(name)
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if tool_class:
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# Create a new instance
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tool_instance = tool_class()
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# Apply configuration if available
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if hasattr(self, 'tool_configs') and name in self.tool_configs:
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tool_instance.config = self.tool_configs[name]
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return tool_instance
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# Fall back to MCP tool instances
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mcp_tool = self._mcp_tool_instances.get(name)
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if mcp_tool:
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return mcp_tool
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return None
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def list_tools(self) -> dict:
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"""
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Get information about all loaded tools.
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:return: A dictionary with tool information.
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"""
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result = {}
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for name, tool_class in self.tool_classes.items():
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# Create a temporary instance to get schema
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temp_instance = tool_class()
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result[name] = {
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"description": temp_instance.description,
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"parameters": temp_instance.get_json_schema()
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}
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# Include MCP tool instances
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for name, mcp_tool in self._mcp_tool_instances.items():
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result[name] = {
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"description": mcp_tool.description,
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"parameters": mcp_tool.params,
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}
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return result
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def shutdown_mcp(self):
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"""Shut down all MCP server clients."""
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if self._mcp_registry:
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self._mcp_registry.shutdown_all()
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