fix(agent): skip auto-compact for sessions with active agent tasks

Prevent proactive compaction from archiving sessions that have an
in-flight agent task, avoiding mid-turn context truncation when a
task runs longer than the idle TTL.

nanobot/agent/autocompact.py

@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+from collections.abc import Collection
 from datetime import datetime
 from typing import TYPE_CHECKING, Any, Callable, Coroutine
 
@@ -23,12 +24,13 @@ class AutoCompact:
         self._archiving: set[str] = set()
         self._summaries: dict[str, tuple[str, datetime]] = {}
 
-    def _is_expired(self, ts: datetime | str | None) -> bool:
+    def _is_expired(self, ts: datetime | str | None,
+                    now: datetime | None = None) -> bool:
         if self._ttl <= 0 or not ts:
             return False
         if isinstance(ts, str):
             ts = datetime.fromisoformat(ts)
-        return (datetime.now() - ts).total_seconds() >= self._ttl * 60
+        return ((now or datetime.now()) - ts).total_seconds() >= self._ttl * 60
 
     @staticmethod
     def _format_summary(text: str, last_active: datetime) -> str:
@@ -56,10 +58,17 @@ class AutoCompact:
         cut = len(tail) - len(kept)
         return tail[:cut], kept
 
-    def check_expired(self, schedule_background: Callable[[Coroutine], None]) -> None:
+    def check_expired(self, schedule_background: Callable[[Coroutine], None],
+                      active_session_keys: Collection[str] = ()) -> None:
+        """Schedule archival for idle sessions, skipping those with in-flight agent tasks."""
+        now = datetime.now()
         for info in self.sessions.list_sessions():
             key = info.get("key", "")
-            if key and key not in self._archiving and self._is_expired(info.get("updated_at")):
+            if not key or key in self._archiving:
+                continue
+            if key in active_session_keys:
+                continue
+            if self._is_expired(info.get("updated_at"), now):
                 self._archiving.add(key)
                 logger.debug("Auto-compact: scheduling archival for {} (idle > {} min)", key, self._ttl)
                 schedule_background(self._archive(key))

nanobot/agent/loop.py

@@ -434,7 +434,10 @@ class AgentLoop:
             try:
                 msg = await asyncio.wait_for(self.bus.consume_inbound(), timeout=1.0)
             except asyncio.TimeoutError:
-                self.auto_compact.check_expired(self._schedule_background)
+                self.auto_compact.check_expired(
+                    self._schedule_background,
+                    active_session_keys=self._pending_queues.keys(),
+                )
                 continue
             except asyncio.CancelledError:
                 # Preserve real task cancellation so shutdown can complete cleanly.