diff --git a/.sisyphus/notepads/visual-modifier-builder/learnings.md b/.sisyphus/notepads/visual-modifier-builder/learnings.md
index cdcb26e..c8a0eba 100644
--- a/.sisyphus/notepads/visual-modifier-builder/learnings.md
+++ b/.sisyphus/notepads/visual-modifier-builder/learnings.md
@@ -664,3 +664,10 @@ Added BlockList wrapping BlockCard with dnd-kit for sorting. Added tests verifyi
 - `bun run check` reports `Test Files  162 passed` covering 1938 unit/integration tests which assert the form and visual components are working.
 - A vitest environment snapshot change occurred where the `ParamField.snapshot.test.tsx` file had 13 snapshots removed/updated; resolved via `bun run test -u packages/chess/src/ui/ParamField.snapshot.test.tsx`.
 - All requirements satisfied per Prompt Task Description.
+
+## QA Verification T24
+- Extended `validateCustomDescriptor` tests with three exact composition level scenarios:
+  1. Depth-3 valid (conditional -> on-move -> add-to-attribute)
+  2. Depth-4 invalid (conditional -> on-move -> conditional -> add-to-attribute) triggering `descriptor.primitives.depth.exceeded`
+  3. Mixed old/new kinds at depth 3 (on-captured -> conditional -> add-aura) valid
+- `bun test packages/chess/src/modifiers/custom/validate.test.ts` passes with 16 test cases.