task 3 and task 4 refined

inference.py

@@ -705,7 +705,7 @@ def choose_action_with_qwen(
             },
         }
 
-    if task_id in {"single_fault", "n_minus_1", "cascade_prevent"}:
+    if task_id in {"single_fault", "n_minus_1"}:
         selected_outcome = choose_best_simulation(
             task_id=task_id,
             observation=observation,

server/graders.py

@@ -126,7 +126,7 @@ def grade_cascade_prevent(
 
 
 def grade_multi_stage_cascade(
-    episode_log: list[EpisodeStepLog], max_steps: int = 25
+    episode_log: list[EpisodeStepLog], max_steps: int = 30
 ) -> float:
     if not episode_log:
         return 0.01

server/tasks.py

@@ -55,10 +55,10 @@ TASKS: Dict[TaskId, TaskSpec] = {
         difficulty="hard",
         description=(
             "Three lines are disconnected and load is increased by 20%. Manage the "
-            "guaranteed three-stage cascade for 25 steps and preserve as much load "
+            "guaranteed three-stage cascade for 30 steps and preserve as much load "
             "as possible across stage boundaries."
         ),
-        max_steps=25,
+        max_steps=30,
     ),
 }