diff --git a/features/dns/client.go b/features/dns/client.go
index 822f102a6..948be683b 100644
--- a/features/dns/client.go
+++ b/features/dns/client.go
@@ -11,6 +11,7 @@ type Client interface {
 	LookupIP(host string) ([]net.IP, error)
 }
 
+// ClientType returns the type of Client interface. Can be used for implementing common.HasType.
 func ClientType() interface{} {
 	return (*Client)(nil)
 }
diff --git a/features/inbound/inbound.go b/features/inbound/inbound.go
index 8c9f0e6e4..51c48d4a1 100644
--- a/features/inbound/inbound.go
+++ b/features/inbound/inbound.go
@@ -30,6 +30,7 @@ type Manager interface {
 	RemoveHandler(ctx context.Context, tag string) error
 }
 
+// ManagerType returns the type of Manager interface. Can be used for implementing common.HasType.
 func ManagerType() interface{} {
 	return (*Manager)(nil)
 }