diff --git a/lnrpc/routerrpc/router.pb.go b/lnrpc/routerrpc/router.pb.go
index f74fb9d3f..a8fa5b0d4 100644
--- a/lnrpc/routerrpc/router.pb.go
+++ b/lnrpc/routerrpc/router.pb.go
@@ -3253,6 +3253,14 @@ type ForwardHtlcInterceptResponse struct {
 	// Any custom records that should be set on the p2p wire message message of
 	// the resumed HTLC. This field is ignored if the action is not
 	// RESUME_MODIFIED.
+	//
+	// If this map is populated, it will overwrite any of the wire custom
+	// records set by LND. It is the caller's responsibility to copy any desired
+	// records across. If the map is empty, no action will be taken and existing
+	// custom records will be propagated.
+	//
+	// The API does not currently support deleting custom records, unless they
+	// are overwritten by a new set.
 	OutWireCustomRecords map[uint64][]byte `protobuf:"bytes,8,rep,name=out_wire_custom_records,json=outWireCustomRecords,proto3" json:"out_wire_custom_records,omitempty" protobuf_key:"varint,1,opt,name=key,proto3" protobuf_val:"bytes,2,opt,name=value,proto3"`
 }
 
diff --git a/lnrpc/routerrpc/router.proto b/lnrpc/routerrpc/router.proto
index 92da75192..6eb928e31 100644
--- a/lnrpc/routerrpc/router.proto
+++ b/lnrpc/routerrpc/router.proto
@@ -1063,6 +1063,14 @@ message ForwardHtlcInterceptResponse {
     // Any custom records that should be set on the p2p wire message message of
     // the resumed HTLC. This field is ignored if the action is not
     // RESUME_MODIFIED.
+    //
+    // If this map is populated, it will overwrite any of the wire custom
+    // records set by LND. It is the caller's responsibility to copy any desired
+    // records across. If the map is empty, no action will be taken and existing
+    // custom records will be propagated.
+    //
+    // The API does not currently support deleting custom records, unless they
+    // are overwritten by a new set.
     map<uint64, bytes> out_wire_custom_records = 8;
 }
 
diff --git a/lnrpc/routerrpc/router.swagger.json b/lnrpc/routerrpc/router.swagger.json
index b838f475d..157e2e7bb 100644
--- a/lnrpc/routerrpc/router.swagger.json
+++ b/lnrpc/routerrpc/router.swagger.json
@@ -1525,7 +1525,7 @@
             "type": "string",
             "format": "byte"
           },
-          "description": "Any custom records that should be set on the p2p wire message message of\nthe resumed HTLC. This field is ignored if the action is not\nRESUME_MODIFIED."
+          "description": "Any custom records that should be set on the p2p wire message message of\nthe resumed HTLC. This field is ignored if the action is not\nRESUME_MODIFIED.\n\nIf this map is populated, it will overwrite any of the wire custom\nrecords set by LND. It is the caller's responsibility to copy any desired\nrecords across. If the map is empty, no action will be taken and existing\ncustom records will be propagated.\n\nThe API does not currently support deleting custom records, unless they\nare overwritten by a new set."
         }
       },
       "description": "*\nForwardHtlcInterceptResponse enables the caller to resolve a previously hold\nforward. The caller can choose either to:\n- `Resume`: Execute the default behavior (usually forward).\n- `ResumeModified`: Execute the default behavior (usually forward) with HTLC\nfield modifications.\n- `Reject`: Fail the htlc backwards.\n- `Settle`: Settle this htlc with a given preimage."