diff --git a/apis/validator/beacon_committee_selections.yaml b/apis/validator/beacon_committee_selections.yaml
index c906012e..333ba787 100644
--- a/apis/validator/beacon_committee_selections.yaml
+++ b/apis/validator/beacon_committee_selections.yaml
@@ -5,8 +5,9 @@ post:
     This endpoint should be used by a validator client running as part of a distributed validator cluster, and is 
     implemented by a distributed validator middleware client. This endpoint is used to exchange partial 
     selection proofs for combined/aggregated selection proofs to allow a validator client 
-    to correctly determine if one of its validators has been selected to perform an aggregation duty in this slot. 
-    Consensus clients need not support this endpoint and may return a 501.
+    to correctly determine if one of its validators has been selected to perform an aggregation duty in a slot. 
+    Validator clients must query this endpoint at the start of an epoch for all validators that have attester duties 
+    in that epoch. Consensus clients need not support this endpoint and may return a 501.
   tags:
     - Validator
   requestBody:
diff --git a/apis/validator/sync_committee_selections.yaml b/apis/validator/sync_committee_selections.yaml
index 857009fd..176bb6f6 100644
--- a/apis/validator/sync_committee_selections.yaml
+++ b/apis/validator/sync_committee_selections.yaml
@@ -6,9 +6,10 @@ post:
     committee selection. This endpoint should be used by a validator client running as part of a distributed 
     validator cluster, and is implemented by a distributed validator middleware client. This endpoint is 
     used to exchange partial selection proof slot signatures for combined/aggregated selection proofs to 
-    allow a validator client to correctly determine if one of its validators has been selected to perform 
-    a sync committee contribution (sync aggregation) duty in this slot. Consensus clients need not support 
-    this endpoint and may return a 501.
+    allow a validator client to correctly determine if one of its validators has been selected to perform a 
+    sync committee contribution (sync aggregation) duty in a slot. Validator clients must query this endpoint
+    at the start of an epoch for all validators that have sync committee contribution duties in that epoch. 
+    Consensus clients need not support this endpoint and may return a 501.
   tags:
     - Validator
   requestBody: