diff --git a/workplans/ILIB-WP-0002-library-infrastructure.md b/workplans/ILIB-WP-0002-library-infrastructure.md
index 438d082..83d5958 100644
--- a/workplans/ILIB-WP-0002-library-infrastructure.md
+++ b/workplans/ILIB-WP-0002-library-infrastructure.md
@@ -159,3 +159,14 @@ Operator decisions:
 Then do a live read-only scan.
 
 Acceptance: one real mail retained with provenance. No mailbox state changed.
+
+Decided 2026-10-05: the mailbox is `library@coulomb.social`. coulomb.social mail is
+hosted by IONOS (MX `mx00/mx01.ionos.de`), the same provider as email-connect's
+`smtp.ionos.de` lane. The library therefore reads `imap.ionos.de:993` over TLS.
+
+Remaining operator steps:
+- confirm the IONOS mailbox exists;
+- deliver its password through the secrets-engine/OpenBao path as
+  `INBOUND_LIBRARY_IMAP_PASSWORD`, with `INBOUND_LIBRARY_IMAP_USER=library@coulomb.social`.
+
+Do not commit or log the password.