diff --git a/TODO b/TODO
index c063ef7e7..f844580f0 100644
--- a/TODO
+++ b/TODO
@@ -16,5 +16,5 @@
 * meta: move-to-head optimization when searching by name on parts (data, func, etc)
 * hashed string: add implicit check on construction for uniqueness (optional)
 * signals on entity creation/destruction
-* flexible views with "composable" filters
+* flexible views with "composable" filters like negative queries: find entites that have components A, B, but not C.
 * review persistent views and avoid indirection to get components