Stabilize task grader discovery paths for Phase 2 validation

openenv.yaml

@@ -20,7 +20,7 @@ tasks:
       are fake, estimate the true final price against the shopper budget,
       and decide if the shopper should proceed.
     difficulty: "easy"
-    grader: "tasks.value_hotel_budget_guard.grader:grade"
+    grader: "guardian_openenv.task_graders:grade_value_hotel_budget_guard"
 
   - id: "airline_seat_upsell_gauntlet"
     name: "Navigate an airline upsell funnel before purchase"
@@ -30,7 +30,7 @@ tasks:
       is fake, calculate the true checkout total, and recommend whether to
       continue.
     difficulty: "medium"
-    grader: "tasks.airline_seat_upsell_gauntlet.grader:grade"
+    grader: "guardian_openenv.task_graders:grade_airline_seat_upsell_gauntlet"
 
   - id: "marketplace_ghost_checkout"
     name: "Run a ghost checkout before the shopper commits"
@@ -40,4 +40,4 @@ tasks:
       verify timers, and determine the real final total before the shopper
       falls for sunk-cost pressure.
     difficulty: "hard"
-    grader: "tasks.marketplace_ghost_checkout.grader:grade"
+    grader: "guardian_openenv.task_graders:grade_marketplace_ghost_checkout"

server/app.py

@@ -72,6 +72,11 @@ def metadata() -> dict:
 @app.get("/tasks")
 def list_tasks() -> list[dict]:
     """List all tasks with metadata — the validator discovers graders here."""
+    grader_by_task_id = {
+        "value_hotel_budget_guard": "guardian_openenv.task_graders:grade_value_hotel_budget_guard",
+        "airline_seat_upsell_gauntlet": "guardian_openenv.task_graders:grade_airline_seat_upsell_gauntlet",
+        "marketplace_ghost_checkout": "guardian_openenv.task_graders:grade_marketplace_ghost_checkout",
+    }
     results = []
     for task in TASKS:
         results.append({
@@ -81,7 +86,7 @@ def list_tasks() -> list[dict]:
             "description": task.objective,
             "difficulty": task.difficulty,
             "has_grader": True,
-            "grader": f"tasks.{task.task_id}.grader:grade",
+            "grader": grader_by_task_id.get(task.task_id, "guardian_openenv.task_graders:grade"),
         })
     return results