diff --git a/.custodian-brief.md b/.custodian-brief.md
index d1669a5..d72a9b2 100644
--- a/.custodian-brief.md
+++ b/.custodian-brief.md
@@ -2,11 +2,19 @@
 # Custodian Brief — flex-auth
 
 **Domain:** infotech  
-**Last synced:** 2026-09-06 20:34 UTC  
+**Last synced:** 2026-09-06 20:45 UTC  
 **State Hub:** http://127.0.0.1:8000 *(adjust if running on a remote machine)*
 
 ## Active Workstreams
 
+### Sign the decision envelope: the response channel is unauthenticated
+Progress: 1/4 done  |  workplan_id: `90577acd-6910-548d-a13e-1dbfdfb8ed27`
+
+**Open tasks:**
+- ! 3. Implement signing and verification  `041612ea`
+- ! 4. Report the gap to gate-house  `82d6b75e`
+- · 2. Choose the signature shape and key custody  `5482f3cd`
+
 ### Operator caller access path and caller identity in the decision record
 Progress: 0/5 done  |  workplan_id: `ad011f92-786c-51ad-b3f6-c06ad77e7af7`