MCP Development Framework

Instructions

Implementation Reference

• mcp_tool/tools/url_tool.py:21-58 (handler)

  The async execute method that handles URL fetching using httpx.AsyncClient, with timeout, redirects, custom User-Agent, and error handling for missing args, timeouts, HTTP errors, and exceptions.

  async def execute(self, arguments: dict) -> list[types.TextContent | types.ImageContent | types.EmbeddedResource]:
      """获取网站内容"""
      if "url" not in arguments:
          return [types.TextContent(
              type="text",
              text="Error: Missing required argument 'url'"
          )]
          
      url = arguments["url"]
      headers = {
          "User-Agent": "MCP Test Server (github.com/modelcontextprotocol/python-sdk)"
      }
      try:
          timeout = httpx.Timeout(10.0, connect=5.0)
          async with httpx.AsyncClient(
              follow_redirects=True, 
              headers=headers,
              timeout=timeout
          ) as client:
              response = await client.get(url)
              response.raise_for_status()
              return [types.TextContent(type="text", text=response.text)]
      except httpx.TimeoutException:
          return [types.TextContent(
              type="text",
              text="Error: Request timed out while trying to fetch the website."
          )]
      except httpx.HTTPStatusError as e:
          return [types.TextContent(
              type="text",
              text=(f"Error: HTTP {e.response.status_code} "
                    "error while fetching the website.")
          )]
      except Exception as e:
          return [types.TextContent(
              type="text",
              text=f"Error: Failed to fetch website: {str(e)}"
          )] 

• mcp_tool/tools/url_tool.py:10-19 (schema)

  The input_schema defining the tool's input as an object requiring a 'url' string parameter.

  input_schema = {
      "type": "object",
      "required": ["url"],
      "properties": {
          "url": {
              "type": "string",
              "description": "URL to fetch",
          }
      },
  }

• mcp_tool/tools/url_tool.py:5-9 (registration)

  Registration via @ToolRegistry.register decorator on UrlTool class, setting name='url' and description.

  @ToolRegistry.register
  class UrlTool(BaseTool):
      """URL获取工具，用于获取网站内容"""
      name = "url"
      description = "Fetches a website and returns its content"