diff --git a/ecomm/0021/SESSION-0021.0-TRANSCRIPT-2026-06-10T08-20--INPROGRESS.md b/ecomm/0021/SESSION-0021.0-TRANSCRIPT-2026-06-10T08-20--INPROGRESS.md
new file mode 100644
index 0000000..0724932
--- /dev/null
+++ b/ecomm/0021/SESSION-0021.0-TRANSCRIPT-2026-06-10T08-20--INPROGRESS.md
@@ -0,0 +1,31 @@
+# Session 0021.0 — Transcript
+
+> App: ecomm
+> Start: 2026-06-10T08-20 (PST)
+> Type: planning-and-executing
+> Claude-Session: 7f254528-630c-4d45-a898-0382927ce8a4
+> Status: **PLACEHOLDER — claimed at session start; finalized at session end.**
+>
+> This file reserves session ID 0021 for ecomm. The driver replaces this
+> body with the full transcript and renames the file to its final
+> SESSION-0021.0-TRANSCRIPT-2026-06-10T08-20--<end>.md form at session end.
+
+## Launch prompt
+
+```
+Implement SLICE-1 (walking skeleton) of SD-0001 v0.3.0 — repo scaffold (4-layer
+backend + import-linter, Vite/React shell, scripts/check.sh, CI), dev Postgres
+compose (single pinned service), platform/db (psycopg) migration runner +
+migration 0001, /healthz, scripts/dev.sh (owns container lifecycle),
+docs/BOOTSTRAP.md (localhost, Docker prereq) — per
+wiggleverse-ecomm-content/specs/SD-0001-mvp-sign-up-and-single-storefront.md §7.2.
+DoD: clean checkout → dev.sh → app up on an empty self-migrated Postgres, check
+gate green in CI.
+
+```
+
+## Deferred decisions
+
+_Autonomous-mode low-confidence calls the driver made and would have
+liked operator input on. Appended as the session runs; surfaced at
+finalize. Empty if none._
diff --git a/ecomm/sessions.json b/ecomm/sessions.json
index 3c3a163..71262a5 100644
--- a/ecomm/sessions.json
+++ b/ecomm/sessions.json
@@ -58,5 +58,8 @@
   },
   "0020": {
     "title": ""
+  },
+  "0021": {
+    "title": ""
   }
 }