fix(agent): expose session timestamps in model context

Include persisted turn timestamps when assembling LLM prompts so relative-date references like yesterday and today have concrete anchors.

Made-with: Cursor

nanobot/agent/loop.py

@@ -832,7 +832,7 @@ class AgentLoop:
             if is_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)
+            history = session.get_history(max_messages=0, include_timestamps=True)
             current_role = "assistant" if is_subagent else "user"
 
             # Subagent content is already in `history` above; passing it again
@@ -901,7 +901,7 @@ class AgentLoop:
             if isinstance(message_tool, MessageTool):
                 message_tool.start_turn()
 
-        history = session.get_history(max_messages=0)
+        history = session.get_history(max_messages=0, include_timestamps=True)
 
         pending_ask_id = pending_ask_user_id(history)
         if pending_ask_id:

nanobot/agent/memory.py

@@ -494,7 +494,7 @@ class Consolidator:
         session_summary: str | None = None,
     ) -> tuple[int, str]:
         """Estimate current prompt size for the normal session history view."""
-        history = session.get_history(max_messages=0)
+        history = session.get_history(max_messages=0, include_timestamps=True)
         channel, chat_id = (session.key.split(":", 1) if ":" in session.key else (None, None))
         probe_messages = self._build_messages(
             history=history,

nanobot/session/manager.py

@@ -30,6 +30,18 @@ class Session:
     metadata: dict[str, Any] = field(default_factory=dict)
     last_consolidated: int = 0  # Number of messages already consolidated to files
 
+    @staticmethod
+    def _annotate_message_time(message: dict[str, Any], content: Any) -> Any:
+        """Expose persisted turn timestamps to the model for relative-date reasoning."""
+        timestamp = message.get("timestamp")
+        if (
+            not timestamp
+            or message.get("role") not in {"user", "assistant"}
+            or not isinstance(content, str)
+        ):
+            return content
+        return f"[Message Time: {timestamp}]\n{content}"
+
     def add_message(self, role: str, content: str, **kwargs: Any) -> None:
         """Add a message to the session."""
         msg = {
@@ -41,7 +53,12 @@ class Session:
         self.messages.append(msg)
         self.updated_at = datetime.now()
 
-    def get_history(self, max_messages: int = 500) -> list[dict[str, Any]]:
+    def get_history(
+        self,
+        max_messages: int = 500,
+        *,
+        include_timestamps: bool = False,
+    ) -> list[dict[str, Any]]:
         """Return unconsolidated messages for LLM input, aligned to a legal tool-call boundary."""
         unconsolidated = self.messages[self.last_consolidated:]
         sliced = unconsolidated[-max_messages:]
@@ -75,6 +92,8 @@ class Session:
                     image_placeholder_text(p) for p in media if isinstance(p, str) and p
                 )
                 content = f"{content}\n{breadcrumbs}" if content else breadcrumbs
+            if include_timestamps:
+                content = self._annotate_message_time(message, content)
             entry: dict[str, Any] = {"role": message["role"], "content": content}
             for key in ("tool_calls", "tool_call_id", "name", "reasoning_content"):
                 if key in message:

tests/agent/test_loop_save_turn.py

@@ -535,7 +535,10 @@ async def test_system_subagent_followup_is_persisted_before_prompt_assembly(tmp_
     )
 
     non_system = [m for m in seen["initial_messages"] if m.get("role") != "system"]
-    assert [m["content"] for m in non_system[:2]] == ["question", "working"]
+    assert "question" in non_system[0]["content"]
+    assert "working" in non_system[1]["content"]
+    assert "[Message Time:" in non_system[0]["content"]
+    assert "[Message Time:" in non_system[1]["content"]
     assert non_system[2]["content"].count("subagent result") == 1
     assert "Current Time:" in non_system[2]["content"]
 

tests/agent/test_session_manager_history.py

@@ -194,6 +194,46 @@ def test_get_history_preserves_reasoning_content():
     ]
 
 
+def test_get_history_exposes_turn_timestamps_to_model():
+    session = Session(key="test:timestamps")
+    session.messages.append({
+        "role": "user",
+        "content": "10 点提醒是昨天发生的",
+        "timestamp": "2026-04-26T22:00:00",
+    })
+    session.messages.append({
+        "role": "assistant",
+        "content": "记下来了",
+        "timestamp": "2026-04-26T22:00:05",
+    })
+
+    history = session.get_history(max_messages=500, include_timestamps=True)
+
+    assert history == [
+        {
+            "role": "user",
+            "content": "[Message Time: 2026-04-26T22:00:00]\n10 点提醒是昨天发生的",
+        },
+        {
+            "role": "assistant",
+            "content": "[Message Time: 2026-04-26T22:00:05]\n记下来了",
+        },
+    ]
+
+
+def test_get_history_does_not_annotate_tool_results_with_timestamps():
+    session = Session(key="test:tool-timestamps")
+    session.messages.append({"role": "user", "content": "run tool"})
+    session.messages.extend(_tool_turn("ts", 0))
+    session.messages[-1]["timestamp"] = "2026-04-26T22:00:10"
+
+    history = session.get_history(max_messages=500, include_timestamps=True)
+
+    tool_result = history[-1]
+    assert tool_result["role"] == "tool"
+    assert tool_result["content"] == "ok"
+
+
 # --- Window cuts mid-group: assistant present but some tool results orphaned ---
 
 def test_window_cuts_mid_tool_group():