diff --git a/mintlify/openapi.yaml b/mintlify/openapi.yaml
index edd1c5018..de388280b 100644
--- a/mintlify/openapi.yaml
+++ b/mintlify/openapi.yaml
@@ -23534,10 +23534,8 @@ components:
                 - type: 'null'
               description: The payment rail used to settle this transaction (e.g. ACH, WIRE, NEFT, FASTER_PAYMENTS). Uses the same values as the PaymentRail sent on quote requests. Null when no external rail is used (e.g. instant or intra-network transfers, or non-direct-destination transactions) or before a rail is resolved.
             railSelectionMode:
-              anyOf:
-                - $ref: '#/components/schemas/RailSelectionMode'
-                - type: 'null'
-              description: How the rail was chosen — MANUAL when the platform specified a paymentRail on the destination, AUTO when Lightspark selects it. Null when no rail is resolved.
+              $ref: '#/components/schemas/RailSelectionMode'
+              description: How the rail was chosen — MANUAL when the platform specified a paymentRail on the destination, AUTO when Lightspark selects it.
             expectedSettlementAt:
               type:
                 - string
diff --git a/openapi.yaml b/openapi.yaml
index edd1c5018..de388280b 100644
--- a/openapi.yaml
+++ b/openapi.yaml
@@ -23534,10 +23534,8 @@ components:
                 - type: 'null'
               description: The payment rail used to settle this transaction (e.g. ACH, WIRE, NEFT, FASTER_PAYMENTS). Uses the same values as the PaymentRail sent on quote requests. Null when no external rail is used (e.g. instant or intra-network transfers, or non-direct-destination transactions) or before a rail is resolved.
             railSelectionMode:
-              anyOf:
-                - $ref: '#/components/schemas/RailSelectionMode'
-                - type: 'null'
-              description: How the rail was chosen — MANUAL when the platform specified a paymentRail on the destination, AUTO when Lightspark selects it. Null when no rail is resolved.
+              $ref: '#/components/schemas/RailSelectionMode'
+              description: How the rail was chosen — MANUAL when the platform specified a paymentRail on the destination, AUTO when Lightspark selects it.
             expectedSettlementAt:
               type:
                 - string
diff --git a/openapi/components/schemas/transactions/OutgoingTransaction.yaml b/openapi/components/schemas/transactions/OutgoingTransaction.yaml
index 19919cc2e..e6b3b1c24 100644
--- a/openapi/components/schemas/transactions/OutgoingTransaction.yaml
+++ b/openapi/components/schemas/transactions/OutgoingTransaction.yaml
@@ -82,13 +82,10 @@ allOf:
           or intra-network transfers, or non-direct-destination transactions)
           or before a rail is resolved.
       railSelectionMode:
-        anyOf:
-          - $ref: ../common/RailSelectionMode.yaml
-          - type: 'null'
+        $ref: ../common/RailSelectionMode.yaml
         description: >-
           How the rail was chosen — MANUAL when the platform specified a
-          paymentRail on the destination, AUTO when Lightspark selects it. Null
-          when no rail is resolved.
+          paymentRail on the destination, AUTO when Lightspark selects it.
       expectedSettlementAt:
         type:
           - string