Trading MCP Server

Instructions

Implementation Reference

• trader_tools.py:104-143 (handler)

  The `unrealized_gains` MCP tool handler calculates the unrealized profit or loss for current stock holdings by comparing the average cost basis against the live market price.

  @mcp.tool()
  def unrealized_gains() -> dict[str, float]:
      """Calculate unrealized gains for current holdings.
  
      This tool calculates unrealized profit or loss by comparing the average
      buy price for currently held shares against the current market price
      fetched live using yfinance.
  
      Returns:
          A dictionary mapping each stock symbol to its unrealized gain or loss in dollars.
  
      Example:
          unrealized_gains() -> {"AAPL": 125.50, "GOOG": -22.15}
      """
      holdings = defaultdict(list)
  
      for _, row in df.iterrows():
          if row['type'] == 'Buy':
              holdings[row['symbol']].append((row['shares'], row['price_per_share']))
          else:
              to_sell = row['shares']
              while to_sell > 0 and holdings[row['symbol']]:
                  qty, price = holdings[row['symbol']][0]
                  matched = min(qty, to_sell)
                  if matched == qty:
                      holdings[row['symbol']].pop(0)
                  else:
                      holdings[row['symbol']][0] = (qty - matched, price)
                  to_sell -= matched
  
      results = {}
      for symbol, buys in holdings.items():
          total_cost = sum(q * p for q, p in buys)
          total_shares = sum(q for q, _ in buys)
          if total_shares == 0:
              continue
          avg_price = total_cost / total_shares
          current = get_live_price(symbol)
          results[symbol] = round((current - avg_price) * total_shares, 2)
      return results