Agentic AI with MCP

Instructions

Implementation Reference

• server.py:129-182 (handler)

  The handler function for 'yahoo_finance_search' tool. It fetches stock data from Yahoo Finance API using the provided symbol and period, extracts key metrics like current price, open, high, low, close, volume, and formats them into a readable string response. The @mcp.tool() decorator registers it with the MCP server.

  @mcp.tool()
  async def yahoo_finance_search(symbol: str, period: str = "1mo") -> str:
      """Get stock information from Yahoo Finance."""
      try:
          valid_periods = ["1d", "5d", "1mo", "3mo", "6mo", "1y", "5y"]
          if period not in valid_periods:
              return f"Invalid period. Must be one of: {', '.join(valid_periods)}"
          
          params = {
              "symbol": symbol,
              "range": period,
              "interval": "1d",
              "includePrePost": "false"
          }
          
          data = await make_api_request(f"{YAHOO_FINANCE_BASE}{symbol}", params=params)
          
          if not data or "chart" not in data or not data["chart"]["result"]:
              return f"Could not retrieve data for symbol {symbol}"
          
          result = data["chart"]["result"][0]
          meta = result["meta"]
          indicators = result["indicators"]["quote"][0]
          
          timestamps = result["timestamp"]
          dates = [datetime.fromtimestamp(ts).strftime('%Y-%m-%d') for ts in timestamps]
          
          latest_idx = -1
          latest_date = dates[latest_idx]
          latest_open = indicators["open"][latest_idx]
          latest_high = indicators["high"][latest_idx]
          latest_low = indicators["low"][latest_idx]
          latest_close = indicators["close"][latest_idx]
          latest_volume = indicators["volume"][latest_idx]
          
          response = [
              f"Stock: {meta['symbol']} ({meta['exchangeName']})",
              f"Currency: {meta['currency']}",
              f"Current Price: {meta['regularMarketPrice']}",
              f"Previous Close: {meta['chartPreviousClose']}",
              "\nLatest Trading Day:",
              f"Date: {latest_date}",
              f"Open: {latest_open}",
              f"High: {latest_high}",
              f"Low: {latest_low}",
              f"Close: {latest_close}",
              f"Volume: {latest_volume}"
          ]
          
          return "\n".join(response)
      except Exception as e:
          logger.error(f"Error in yahoo_finance_search: {e}")
          return f"Failed to retrieve finance data for {symbol} due to an internal error."

• server.py:129-129 (registration)

  The @mcp.tool() decorator registers the yahoo_finance_search function as an MCP tool.

  @mcp.tool()