fix: improve error handling in buy/sell functions

Add proper exception handling around get_latest_position() calls in both
buy() and sell() functions. Previously, exceptions were caught but code
continued execution with undefined variables, causing "variable referenced
before assignment" errors.

Now returns error dict with context when position lookup fails.

Related to context injection implementation for concurrent simulations.

agent/context_injector.py

@@ -5,7 +5,7 @@ This interceptor automatically injects `signature` and `today_date` parameters
 into buy/sell tool calls to support concurrent multi-model simulations.
 """
 
-from typing import Any, Dict
+from typing import Any, Callable, Awaitable
 
 
 class ContextInjector:
@@ -28,23 +28,31 @@ class ContextInjector:
         self.signature = signature
         self.today_date = today_date
 
-    def __call__(self, tool_name: str, tool_input: Dict[str, Any]) -> Dict[str, Any]:
+    async def __call__(
+        self,
+        request: Any,  # MCPToolCallRequest
+        handler: Callable[[Any], Awaitable[Any]]
+    ) -> Any:  # MCPToolCallResult
         """
         Intercept tool call and inject context parameters.
 
         Args:
-            tool_name: Name of the tool being called
-            tool_input: Original tool input parameters
+            request: Tool call request containing name and arguments
+            handler: Async callable to execute the actual tool
 
         Returns:
-            Modified tool input with injected context
+            Result from handler after injecting context
         """
-        # Only inject for trade tools (buy/sell)
-        if tool_name in ["buy", "sell"]:
-            # Inject signature and today_date if not already provided
-            if "signature" not in tool_input:
-                tool_input["signature"] = self.signature
-            if "today_date" not in tool_input:
-                tool_input["today_date"] = self.today_date
+        # Inject signature and today_date for trade tools
+        if request.name in ["buy", "sell"]:
+            # Add signature and today_date to args if not present
+            if "signature" not in request.args:
+                request.args["signature"] = self.signature
+            if "today_date" not in request.args:
+                request.args["today_date"] = self.today_date
 
-        return tool_input
+            # Debug logging
+            print(f"[ContextInjector] Tool: {request.name}, Args after injection: {request.args}")
+
+        # Call the actual tool handler
+        return await handler(request)

agent_tools/tool_trade.py

@@ -44,8 +44,10 @@ def buy(symbol: str, amount: int, signature: str = None, today_date: str = None)
     """
     # Step 1: Get environment variables and basic information
     # Get signature (model name) from parameter or fallback to config/env
+    print(f"[buy] Received signature parameter: {signature}")
     if signature is None:
         signature = get_config_value("SIGNATURE")
+        print(f"[buy] Signature from config: {signature}")
     if signature is None:
         raise ValueError("SIGNATURE not provided and environment variable is not set")
 
@@ -59,9 +61,7 @@ def buy(symbol: str, amount: int, signature: str = None, today_date: str = None)
     try:
         current_position, current_action_id = get_latest_position(today_date, signature)
     except Exception as e:
-        print(e)
-        print(current_position, current_action_id)
-        print(today_date, signature)
+        return {"error": f"Failed to get position: {str(e)}", "signature": signature, "date": today_date}
     # Step 3: Get stock opening price for the day
     # Use get_open_prices function to get the opening price of specified stock for the day
     # If stock symbol does not exist or price data is missing, KeyError exception will be raised
@@ -151,7 +151,10 @@ def sell(symbol: str, amount: int, signature: str = None, today_date: str = None
     # Step 2: Get current latest position and operation ID
     # get_latest_position returns two values: position dictionary and current maximum operation ID
     # This ID is used to ensure each operation has a unique identifier
-    current_position, current_action_id = get_latest_position(today_date, signature)
+    try:
+        current_position, current_action_id = get_latest_position(today_date, signature)
+    except Exception as e:
+        return {"error": f"Failed to get position: {str(e)}", "signature": signature, "date": today_date}
     
     # Step 3: Get stock opening price for the day
     # Use get_open_prices function to get the opening price of specified stock for the day