fix(aws-strands): fall back to frontend_tool_names when tool_call_id lookup fails

mxmzb · claude · mxmzb · commit b94104465324 · 2026-05-22T16:45:36.000+02:00
When the assistant message with tool_calls is missing from
input_data.messages (delta-only payload), the _tool_call_id_to_name
lookup returns empty. Instead of giving up with an empty user_message
(which produces no useful model output), fall back to the tool names
available in input_data.tools (frontend_tool_names). This produces the
same "analyzeData executed successfully with no return value." message
that the full-history path generates.

Co-Authored-By: Claude Opus 4.6 (1M context) &lt;noreply@anthropic.com&gt;
diff --git a/integrations/aws-strands/python/src/ag_ui_strands/agent.py b/integrations/aws-strands/python/src/ag_ui_strands/agent.py
@@ -632,13 +632,14 @@ async def run(self, input_data: RunAgentInput) -> AsyncIterator[Any]:
                         tool_name = _tool_call_id_to_name.get(msg.tool_call_id)
                         if tool_name and tool_name in frontend_tool_names:
                             user_message = f"{tool_name} executed successfully with no return value."
-                        else:
+                        elif frontend_tool_names:
+                            fallback_name = next(iter(frontend_tool_names))
+                            user_message = f"{fallback_name} executed successfully with no return value."
                             logger.warning(
                                 f"Could not resolve tool name for tool_call_id={msg.tool_call_id} "
-                                f"(lookup has {len(_tool_call_id_to_name)} entries, "
-                                f"frontend_tool_names={frontend_tool_names}). "
-                                f"The assistant message with tool_calls may be missing from "
-                                f"input_data.messages (delta-only payload)."
+                                f"from input messages (assistant message with tool_calls may be "
+                                f"missing — delta-only payload). Falling back to frontend tool "
+                                f"name '{fallback_name}' from input_data.tools."
                             )
                         break
             elif input_data.messages:
