Fix MangenticAgentExecutor producing repr str for tool call content (#2566)

python/packages/core/agent_framework/_workflows/_magentic.py

@@ -1727,7 +1727,7 @@ class MagenticAgentExecutor(Executor):
             last: ChatMessage = messages[-1]
             author = last.author_name or self._agent_id
             role: Role = last.role if last.role else Role.ASSISTANT
-            text = last.text or str(last)
+            text = last.text or ""
             msg = ChatMessage(role=role, text=text, author_name=author)
             await self._emit_agent_message_event(ctx, msg)
             return msg

python/packages/devui/agent_framework_devui/_mapper.py

@@ -1274,7 +1274,7 @@ class MessageMapper:
                             "trace_type": "magentic_orchestrator",
                             "orchestrator_id": orchestrator_id,
                             "kind": kind,
-                            "text": text or str(message),
+                            "text": text or "",
                             "timestamp": datetime.now().isoformat(),
                         },
                         span_id=f"magentic_orch_{uuid4().hex[:8]}",