fix(loop): persist subagent follow-up events in history

nanobot/agent/loop.py

@@ -647,13 +647,17 @@ class AgentLoop:
             session, pending = self.auto_compact.prepare_session(session, key)
 
             await self.consolidator.maybe_consolidate_by_tokens(session)
+            if msg.sender_id == "subagent" and self._persist_subagent_followup(session, msg):
+                self.sessions.save(session)
             self._set_tool_context(channel, chat_id, msg.metadata.get("message_id"))
             history = session.get_history(max_messages=0)
             current_role = "assistant" if msg.sender_id == "subagent" else "user"
 
             messages = self.context.build_messages(
                 history=history,
-                current_message=msg.content, channel=channel, chat_id=chat_id,
+                current_message="" if msg.sender_id == "subagent" else msg.content,
+                channel=channel,
+                chat_id=chat_id,
                 session_summary=pending,
                 current_role=current_role,
             )
@@ -870,6 +874,23 @@ class AgentLoop:
             session.messages.append(entry)
         session.updated_at = datetime.now()
 
+    def _persist_subagent_followup(self, session: Session, msg: InboundMessage) -> bool:
+        """Persist subagent follow-ups before prompt assembly so history stays durable."""
+        task_id = msg.metadata.get("subagent_task_id") if isinstance(msg.metadata, dict) else None
+        if task_id and any(
+            m.get("injected_event") == "subagent_result" and m.get("subagent_task_id") == task_id
+            for m in session.messages
+        ):
+            return False
+        session.add_message(
+            "assistant",
+            msg.content,
+            sender_id=msg.sender_id,
+            injected_event="subagent_result",
+            subagent_task_id=task_id,
+        )
+        return True
+
     def _set_runtime_checkpoint(self, session: Session, payload: dict[str, Any]) -> None:
         """Persist the latest in-flight turn state into session metadata."""
         session.metadata[self._RUNTIME_CHECKPOINT_KEY] = payload

nanobot/agent/subagent.py

@@ -246,6 +246,10 @@ class SubagentManager:
             sender_id="subagent",
             chat_id=f"{origin['channel']}:{origin['chat_id']}",
             content=announce_content,
+            metadata={
+                "injected_event": "subagent_result",
+                "subagent_task_id": task_id,
+            },
         )
 
         await self.bus.publish_inbound(msg)