diff --git a/docs/modernization/debt.md b/docs/modernization/debt.md
index 440e8a2..a2ca44f 100644
--- a/docs/modernization/debt.md
+++ b/docs/modernization/debt.md
@@ -85,6 +85,10 @@ agent or engineer to remove them without reconstructing context from chat.
   `execute_legacy_canvas_draw_merge_temporary_composite(...)`; the retained
   path still owns the concrete setup, sampler, texture, draw, and unbind
   callbacks.
+- 2026-06-13: DEBT-0036 was narrowed again. `Canvas::draw_merge()` now routes
+  the remaining temporary erase and paint callback bundle through
+  `execute_legacy_canvas_draw_merge_temporary_composite(...)`; branch
+  selection remains in `Canvas`.
 - 2026-06-13: DEBT-0036 was narrowed again. `NodeStrokePreview::draw_stroke_immediate()`
   now routes retained preview feedback/material/composite planning plus stroke
   shader uniform assembly through
diff --git a/docs/modernization/tasks.md b/docs/modernization/tasks.md
index cc7cbe4..77d0388 100644
--- a/docs/modernization/tasks.md
+++ b/docs/modernization/tasks.md
@@ -665,6 +665,11 @@ Progress Notes:
   the retained path still owns the concrete setup, sampler, texture, draw, and
   unbind callbacks. Next slice should target another narrow draw-merge seam
   without reopening the landed temporary-composite helper.
+- 2026-06-13: `Canvas::draw_merge()` now routes the remaining temporary erase
+  and paint callback bundle through
+  `execute_legacy_canvas_draw_merge_temporary_composite(...)`; only the
+  branch selection remains inline. Next slice should target another narrow
+  draw-merge seam without reopening the landed temporary-composite helper.
 - 2026-06-13: `pp_paint_renderer_stroke_execution_tests` now also covers
   retained frame-plan assembly for previous-sample projection mode and zoom
   scaling. Next slice should target the remaining preview/Canvas stroke