diff --git a/docs/handoff/membership-backend-checklist.md b/docs/handoff/membership-backend-checklist.md
index 1b433b1..5e736bc 100644
--- a/docs/handoff/membership-backend-checklist.md
+++ b/docs/handoff/membership-backend-checklist.md
@@ -99,6 +99,9 @@ Must return:
    - `sponsor_org_root_id` is provided,
    - payer wallet is an `org_root_owner` principal for that org root,
    - payer entitlement status is active.
+10. Optional strict chain verification mode:
+   - when `SECRET_API_REQUIRE_ONCHAIN_TX_VERIFICATION=true`,
+   - membership confirm must fail closed if chain RPC verification is unavailable.
 
 ## Data Persistence Requirements