Yahoo Finance MCP Server

Instructions

Implementation Reference

• server.py:622-647 (handler)

  The core handler function for the 'get_option_chain' tool. It retrieves option chain data from the Financial Modeling Prep API for a given ticker, filters by expiration date and option type (calls/puts), handles errors, and returns filtered JSON data.

  async def get_option_chain(ticker: str, expiration_date: str, option_type: str) -> str:
      """Fetch the option chain for a given ticker symbol, expiration date, and option type."""
  
      api_key = os.environ.get("FMP_API_KEY")
      if not api_key:
          return "Error: FMP_API_KEY environment variable not set."
  
      base = "https://financialmodelingprep.com/api/v3"
      try:
          resp = requests.get(
              f"{base}/options/chain/{ticker}",
              params={"expiration": expiration_date, "apikey": api_key},
              timeout=10,
          )
          resp.raise_for_status()
          data = resp.json()
      except Exception as e:
          return f"Error: getting option chain for {ticker}: {e}"
  
      filtered = [
          item
          for item in data
          if item.get("expirationDate") == expiration_date
          and item.get("optionType", "").lower() == option_type.lower()
      ]
      return json.dumps(filtered)

• server.py:609-621 (registration)

  The @fmp_server.tool decorator registers the 'get_option_chain' tool, specifying its name and detailed description including input parameters (schema). This is how the tool is exposed in the MCP server.

  @fmp_server.tool(
      name="get_option_chain",
      description="""根据股票代码、到期日和期权类型获取期权链数据。
  
  参数说明：
      ticker: str
          股票代码，例如 "AAPL"
      expiration_date: str
          期权到期日，格式为 'YYYY-MM-DD'
      option_type: str
          期权类型：'calls' 或 'puts'
  """,
  )

• server.py:622-622 (schema)

  Type hints in the function signature define the input schema: ticker (str), expiration_date (str), option_type (str), returning str (JSON).

  async def get_option_chain(ticker: str, expiration_date: str, option_type: str) -> str: