diff --git a/AUDIT.md b/AUDIT.md
index 3077c04..cf33c1f 100644
--- a/AUDIT.md
+++ b/AUDIT.md
@@ -177,3 +177,11 @@ severity levels. All critical and high issues resolved.
 | A-015 | Medium | Open |
 | A-016 | Low | Open |
 | A-017 | Low | Open |
+
+## Design Note: Single-User Model
+
+This server is designed for a single authenticated user. The users
+table and multi-user schema exist but are used for one account only.
+If multi-user support is ever needed, authentication will migrate to
+MCIAS (Metacircular Identity and Access Service) — the standalone
+auth implementation here will not be extended for multiple users.