feat: reset bot session context while retaining monitoring history

src/langbot/pkg/agent/runner/context_reset.py

@@ -0,0 +1,46 @@
+"""Scoped context reset markers, independent of retained monitoring history."""
+
+import hashlib
+import json
+
+import sqlalchemy as sa
+
+from ...entity.persistence.runner_state import RunnerState
+
+HOST_RESET_RUNNER = '__langbot_context_reset__'
+
+
+def reset_scope(workspace, bot, conversation):
+    return 'host-reset:' + hashlib.sha256(json.dumps([workspace, bot, conversation]).encode()).hexdigest()
+
+
+async def get_reset_generation(engine, workspace, bot, conversation):
+    if not all((workspace, bot, conversation)):
+        return None
+    async with engine.connect() as connection:
+        value = (
+            await connection.execute(
+                sa.select(RunnerState.value_json).where(
+                    RunnerState.scope_key == reset_scope(workspace, bot, conversation),
+                    RunnerState.state_key == 'generation',
+                    RunnerState.runner_id == HOST_RESET_RUNNER,
+                )
+            )
+        ).scalar_one_or_none()
+    return json.loads(value) if value else None
+
+
+def active_history_condition(transcript):
+    cutoff = (
+        sa.select(sa.func.max(RunnerState.created_at))
+        .where(
+            RunnerState.runner_id == HOST_RESET_RUNNER,
+            RunnerState.state_key == 'generation',
+            RunnerState.workspace_id == transcript.workspace_id,
+            RunnerState.bot_id == transcript.bot_id,
+            RunnerState.conversation_id == transcript.conversation_id,
+        )
+        .correlate(transcript)
+        .scalar_subquery()
+    )
+    return sa.or_(cutoff.is_(None), transcript.created_at > cutoff)

src/langbot/pkg/agent/runner/persistent_state_store.py

@@ -191,7 +191,9 @@ class PersistentStateStore:
         # Seed external.conversation_id from event.conversation_id if not set
         if self._check_scope_enabled('conversation', binding) and event.conversation_id:
             if 'external.conversation_id' not in snapshot['conversation']:
-                snapshot['conversation']['external.conversation_id'] = event.conversation_id
+                from .context_reset import get_reset_generation
+                generation = await get_reset_generation(self._db_engine, event.workspace_id, event.bot_id, event.conversation_id)
+                snapshot['conversation']['external.conversation_id'] = generation or event.conversation_id
 
         return snapshot
 

src/langbot/pkg/agent/runner/transcript_store.py

@@ -335,6 +335,8 @@ class TranscriptStore:
         thread_id: str | None,
         strict_thread: bool,
     ) -> typing.Any:
+        from .context_reset import active_history_condition
+        query = query.where(active_history_condition(Transcript))
         if bot_id is not None:
             query = query.where(Transcript.bot_id == bot_id)
         if workspace_id is not None: