Handle return value from schwab api

Author: major

src/schwab_mcp/tools/utils.py

@@ -14,7 +14,17 @@ async def call(func: Callable[..., Awaitable[Any]], *args: Any, **kwargs: Any) -
     response = await func(*args, **kwargs)
     response.raise_for_status()
 
-    if getattr(response, "status_code", None) == 204:
+    # Handle responses with no content
+    # 204 No Content: explicit no-content response
+    # 201 Created: order placement endpoints return empty body with Location header
+    status_code = getattr(response, "status_code", None)
+    if status_code in (201, 204):
+        return None
+
+    # Check if response has content before trying to parse JSON
+    # Some endpoints (like place_order) return empty bodies even with 2xx status
+    content = getattr(response, "content", b"")
+    if not content or len(content) == 0:
         return None
 
     try: