diff --git a/supabase/migrations/20260807001200_attendance_status_values.sql b/supabase/migrations/20260807001200_attendance_status_values.sql
new file mode 100644
index 0000000..1a1f6f1
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+++ b/supabase/migrations/20260807001200_attendance_status_values.sql
@@ -0,0 +1,12 @@
+-- Attendance state expansion — spec section 16.
+--
+-- The visual state system needs vacation as a first-class state alongside
+-- present / absent / late / excused. "Not yet marked" is the absence of a row,
+-- so it needs no enum member.
+--
+-- Enum values cannot be used in the transaction that adds them, and the
+-- Supabase CLI wraps each file in one transaction, so this file adds values and
+-- nothing else. 20260807001300 is where they are used.
+
+ALTER TYPE public.attendance_status ADD VALUE IF NOT EXISTS 'vacation';
+ALTER TYPE public.attendance_status ADD VALUE IF NOT EXISTS 'holiday';