Fix score - shift rewards to positive range, never 0.0 or 1.0

inference.py

@@ -223,27 +223,30 @@ def run_episode(client: OpenAI, difficulty: str, task_id: str) -> dict:
                 break
 
         # Score strictly between 0 and 1 exclusive
+        # Score strictly between 0 and 1 exclusive — never 0.0 or 1.0
         if rewards:
-            total_reward = sum(rewards)
-            raw_score = max(0.1, total_reward / len(rewards))
+            # Shift all rewards to positive range first
+            shifted = [max(0.01, r + 0.5) for r in rewards]
+            raw_score = sum(shifted) / len(shifted)
         else:
-            raw_score = 0.1
+            raw_score = 0.5
 
         score   = max(0.001, min(0.999, raw_score))
         success = score >= SUCCESS_SCORE_THRESHOLD
 
     except Exception as e:
         print(f"[DEBUG] Episode error: {e}", flush=True)
-        score   = 0.1
+        score   = 0.5
         success = False
 
     finally:
+        # Ensure rewards list for log_end is never empty and never contains 0.0
+        safe_rewards = [max(0.01, r + 0.5) for r in rewards] if rewards else [0.5]
         log_end(
             success = success,
             steps   = steps,
-            rewards = rewards if rewards else [0.1]
+            rewards = safe_rewards
         )
-
     return {
         "task_id":    task_id,
         "difficulty": difficulty,