diff --git a/backend-tests/OperationsSnapshotTests.cs b/backend-tests/OperationsSnapshotTests.cs
index f78982f..1be6ade 100644
--- a/backend-tests/OperationsSnapshotTests.cs
+++ b/backend-tests/OperationsSnapshotTests.cs
@@ -109,6 +109,9 @@ internal sealed class GuardedActivityRepository(RepositoryConcurrencyGuard guard
             new() { Id = 1, Type = "agent", Message = "recent activity", CreatedAt = DateTimeOffset.UtcNow }
         }, ct);
 
+    public Task<List<ActivityEvent>> GetRecentForTasksAsync(IEnumerable<Guid> taskIds, CancellationToken ct = default)
+        => guard.RunAsync(new List<ActivityEvent>(), ct);
+
     public Task<(List<ActivityEvent> Items, int TotalCount)> GetPagedAsync(string? type, string? sort, int page, int pageSize, CancellationToken ct = default)
         => throw new NotSupportedException();