fix(session): remove message time replay prefixes

nanobot/agent/loop.py

@@ -1183,7 +1183,6 @@ class AgentLoop:
         _hist_kwargs: dict[str, Any] = {
             "max_messages": self._max_messages,
             "max_tokens": self._replay_token_budget(),
-            "include_timestamps": True,
             "extend_to_user": is_subagent,
         }
         history = session.get_history(**_hist_kwargs)
@@ -1462,7 +1461,6 @@ class AgentLoop:
         _hist_kwargs: dict[str, Any] = {
             "max_messages": self._max_messages,
             "max_tokens": self._replay_token_budget(),
-            "include_timestamps": True,
             "extend_to_user": False,
         }
         ctx.history = ctx.session.get_history(**_hist_kwargs)

nanobot/agent/memory.py

@@ -712,17 +712,12 @@ class Consolidator:
     @staticmethod
     def _full_unconsolidated_history(
         session: Session,
-        *,
-        include_timestamps: bool = False,
     ) -> list[dict[str, Any]]:
         """Return the whole unconsolidated tail for consolidation decisions."""
         unconsolidated_count = len(session.messages) - session.last_consolidated
         if unconsolidated_count <= 0:
             return []
-        return session.get_history(
-            max_messages=unconsolidated_count,
-            include_timestamps=include_timestamps,
-        )
+        return session.get_history(max_messages=unconsolidated_count)
 
     @staticmethod
     def _replay_overflow_boundary(
@@ -797,7 +792,7 @@ class Consolidator:
         session: Session,
     ) -> tuple[int, str]:
         """Estimate prompt size from the full unconsolidated session tail."""
-        history = self._full_unconsolidated_history(session, include_timestamps=True)
+        history = self._full_unconsolidated_history(session)
         channel, chat_id = (session.key.split(":", 1) if ":" in session.key else (None, None))
         # Include archived summary in estimation so the budget accounts for it.
         meta = session.metadata.get("_last_summary")

nanobot/session/manager.py

@@ -118,25 +118,6 @@ class Session:
         ):
             self.last_consolidated = 0
 
-    @staticmethod
-    def _annotate_message_time(message: dict[str, Any], content: Any) -> Any:
-        """Expose persisted turn timestamps to the model for relative-date reasoning.
-
-        Annotating *every* assistant turn trains the model (via in-context
-        demonstrations) to start its own replies with the same
-        ``[Message Time: ...]`` prefix, which leaks metadata back to the user.
-        We therefore only annotate user turns. User-side stamps are enough to
-        pin adjacent assistant replies for relative-time reasoning, including
-        proactive messages the user replies to later.
-        """
-        timestamp = message.get("timestamp")
-        if not timestamp or not isinstance(content, str):
-            return content
-        role = message.get("role")
-        if role != "user":
-            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 = {
@@ -153,7 +134,6 @@ class Session:
         max_messages: int = 120,
         *,
         max_tokens: int = 0,
-        include_timestamps: bool = False,
         extend_to_user: bool = False,
     ) -> list[dict[str, Any]]:
         """Return unconsolidated messages for LLM input.
@@ -243,8 +223,6 @@ class Session:
                 if mcp_lines:
                     breadcrumbs = "\n".join(mcp_lines)
                     content = f"{content}\n{breadcrumbs}" if content else breadcrumbs
-            if include_timestamps:
-                content = self._annotate_message_time(message, content)
             if role == "assistant" and isinstance(content, str) and not content.strip():
                 if not any(key in message for key in ("tool_calls", "reasoning_content", "thinking_blocks")):
                     continue