diff --git a/server.py b/server.py
index ada0d10..d10162a 100644
--- a/server.py
+++ b/server.py
@@ -406,28 +406,30 @@ async def discard_run(run_id: str, username: str = Depends(get_required_user)):
     if run.username not in (username, actor_id):
         raise HTTPException(403, "Access denied")
 
-    # Check if activity exists for this run
-    activity = cache_manager.get_activity(run_id)
+    # Failed runs can always be deleted (no output to protect)
+    if run.status != "failed":
+        # Check if activity exists for this run
+        activity = cache_manager.get_activity(run_id)
 
-    if activity:
-        # Use activity manager deletion rules
-        can_discard, reason = cache_manager.can_discard_activity(run_id)
-        if not can_discard:
-            raise HTTPException(400, f"Cannot discard run: {reason}")
+        if activity:
+            # Use activity manager deletion rules
+            can_discard, reason = cache_manager.can_discard_activity(run_id)
+            if not can_discard:
+                raise HTTPException(400, f"Cannot discard run: {reason}")
 
-        # Discard the activity (cleans up cache entries)
-        success, msg = cache_manager.discard_activity(run_id)
-        if not success:
-            raise HTTPException(500, f"Failed to discard: {msg}")
-    else:
-        # Legacy run without activity record - check L2 shared status manually
-        items_to_check = list(run.inputs or [])
-        if run.output_hash:
-            items_to_check.append(run.output_hash)
+            # Discard the activity (cleans up cache entries)
+            success, msg = cache_manager.discard_activity(run_id)
+            if not success:
+                raise HTTPException(500, f"Failed to discard: {msg}")
+        else:
+            # Legacy run without activity record - check L2 shared status manually
+            items_to_check = list(run.inputs or [])
+            if run.output_hash:
+                items_to_check.append(run.output_hash)
 
-        for content_hash in items_to_check:
-            if cache_manager.l2_checker.is_shared(content_hash):
-                raise HTTPException(400, f"Cannot discard run: item {content_hash[:16]}... is published to L2")
+            for content_hash in items_to_check:
+                if cache_manager.l2_checker.is_shared(content_hash):
+                    raise HTTPException(400, f"Cannot discard run: item {content_hash[:16]}... is published to L2")
 
     # Remove from Redis
     redis_client.delete(f"{RUNS_KEY_PREFIX}{run_id}")