diff --git a/plans/artdag-on-sx.md b/plans/artdag-on-sx.md
index f5f7cbab..1f005f50 100644
--- a/plans/artdag-on-sx.md
+++ b/plans/artdag-on-sx.md
@@ -138,6 +138,10 @@ lib/artdag/optimize.sx                  lib/artdag/federation.sx
 
 ## Progress log
 
+- **Ext: public API facade** (`lib/artdag/api.sx`, total 158/158 unchanged).
+  Reference index matching the datalog/persist convention: canonical load order +
+  the full public surface across all 10 modules + `artdag/version`.
+
 - **Ext: fault-tolerant execution** (fault suite 14/14, total 158/158).
   `lib/artdag/fault.sx`: a node op may fail via `(artdag/fail reason)`; `run-safe`
   confines the failure to that node + its transitive dependents (independent branches