refactor: implement snippet truncation for task descriptions and comments

backend/app/api/tasks.py

@@ -64,6 +64,8 @@ TASK_EVENT_TYPES = {
     "task.comment",
 }
 SSE_SEEN_MAX = 2000
+TASK_SNIPPET_MAX_LEN = 500
+TASK_SNIPPET_TRUNCATED_LEN = 497
 
 
 def _comment_validation_error() -> HTTPException:
@@ -83,6 +85,13 @@ def _blocked_task_error(blocked_by_task_ids: Sequence[UUID]) -> HTTPException:
     )
 
 
+def _truncate_snippet(value: str) -> str:
+    text = value.strip()
+    if len(text) <= TASK_SNIPPET_MAX_LEN:
+        return text
+    return f"{text[:TASK_SNIPPET_TRUNCATED_LEN]}..."
+
+
 async def has_valid_recent_comment(
     session: AsyncSession,
     task: Task,
@@ -282,9 +291,7 @@ async def _notify_agent_on_task_assign(
     config = await _gateway_config(session, board)
     if config is None:
         return
-    description = (task.description or "").strip()
+    description = _truncate_snippet(task.description or "")
-    if len(description) > 500:
-        description = f"{description[:497]}..."
     details = [
         f"Board: {board.name}",
         f"Task: {task.title}",
@@ -340,9 +347,7 @@ async def _notify_lead_on_task_create(
     config = await _gateway_config(session, board)
     if config is None:
         return
-    description = (task.description or "").strip()
+    description = _truncate_snippet(task.description or "")
-    if len(description) > 500:
-        description = f"{description[:497]}..."
     details = [
         f"Board: {board.name}",
         f"Task: {task.title}",
@@ -397,9 +402,7 @@ async def _notify_lead_on_task_unassigned(
     config = await _gateway_config(session, board)
     if config is None:
         return
-    description = (task.description or "").strip()
+    description = _truncate_snippet(task.description or "")
-    if len(description) > 500:
-        description = f"{description[:497]}..."
     details = [
         f"Board: {board.name}",
         f"Task: {task.title}",
@@ -486,13 +489,11 @@ async def stream_tasks(
                 if len(seen_queue) > SSE_SEEN_MAX:
                     oldest = seen_queue.popleft()
                     seen_ids.discard(oldest)
-                if event.created_at > last_seen:
+                last_seen = max(event.created_at, last_seen)
-                    last_seen = event.created_at
                 payload: dict[str, object] = {"type": event.event_type}
                 if event.event_type == "task.comment":
                     payload["comment"] = _serialize_comment(event)
-                else:
+                elif task is None:
-                    if task is None:
                     payload["task"] = None
                 else:
                     dep_list = deps_map.get(task.id, [])
@@ -891,11 +892,8 @@ async def update_task(
     task.updated_at = utcnow()
 
     if "status" in updates and updates["status"] == "review":
-        if comment is not None and comment.strip():
+        comment_text = (comment or "").strip()
-            if not comment.strip():
+        if not comment_text and not await has_valid_recent_comment(
-                raise _comment_validation_error()
-        else:
-            if not await has_valid_recent_comment(
             session,
             task,
             task.assigned_agent_id,
@@ -1083,9 +1081,7 @@ async def create_task_comment(
         board = await Board.objects.by_id(task.board_id).first(session) if task.board_id else None
         config = await _gateway_config(session, board) if board else None
         if board and config:
-            snippet = payload.message.strip()
+            snippet = _truncate_snippet(payload.message)
-            if len(snippet) > 500:
-                snippet = f"{snippet[:497]}..."
             actor_name = actor.agent.name if actor.actor_type == "agent" and actor.agent else "User"
             for agent in targets.values():
                 if not agent.openclaw_session_id: