MCP Policy Gatekeeper

Instructions

Implementation Reference

• server.py:201-211 (handler)

  Handler for the 'list_files' tool. Resolves the directory path, recursively finds all files using rglob('*'), collects relative paths of files only, sorts them, and returns as a newline-separated text content.

  elif name == "list_files":
      dir_path = resolve_path(arguments.get("path", ""))
      if not dir_path.exists():
          return [TextContent(type="text", text="Error: Directory not found")]
      
      files = []
      for item in dir_path.rglob("*"):
          if item.is_file():
              files.append(str(item.relative_to(PROTECTED_DIR)))
      
      return [TextContent(type="text", text="\n".join(sorted(files)) if files else "No files found")]

• server.py:123-132 (registration)

  Registration of the 'list_files' tool in the list_tools() function, including its description and input schema.

  Tool(
      name="list_files",
      description="List all files in directory",
      inputSchema={
          "type": "object",
          "properties": {
              "path": {"type": "string", "description": "Directory path", "default": ""}
          }
      }
  )

• server.py:126-131 (schema)

  Input schema for the 'list_files' tool: an object with optional 'path' string property defaulting to empty string.

  inputSchema={
      "type": "object",
      "properties": {
          "path": {"type": "string", "description": "Directory path", "default": ""}
      }
  }