diff --git a/ecomm/0012/SESSION-0012.0-TRANSCRIPT-2026-06-03T19-45--INPROGRESS.md b/ecomm/0012/SESSION-0012.0-TRANSCRIPT-2026-06-03T19-45--INPROGRESS.md
new file mode 100644
index 0000000..9bb22b3
--- /dev/null
+++ b/ecomm/0012/SESSION-0012.0-TRANSCRIPT-2026-06-03T19-45--INPROGRESS.md
@@ -0,0 +1,13 @@
+# Session 0012.0 — Transcript
+
+> App: ecomm
+> Start: 2026-06-03T19-45 (PST)
+> Status: **PLACEHOLDER — claimed at session start; finalized at session end.**
+>
+> This file reserves session ID 0012 for ecomm. The driver replaces this
+> body with the full transcript and renames the file to its final
+> SESSION-0012.0-TRANSCRIPT-2026-06-03T19-45--<end>.md form at session end.
+
+## Launch prompt
+
+_(launch prompt not captured at claim time)_
diff --git a/ecomm/sessions.json b/ecomm/sessions.json
index 717318e..575794d 100644
--- a/ecomm/sessions.json
+++ b/ecomm/sessions.json
@@ -31,5 +31,8 @@
   },
   "0011": {
     "title": ""
+  },
+  "0012": {
+    "title": ""
   }
 }