diff --git a/src/github.com/matrix-org/dendrite/roomserver/input/consumer.go b/src/github.com/matrix-org/dendrite/roomserver/input/consumer.go
index f299861a0..2c50103b4 100644
--- a/src/github.com/matrix-org/dendrite/roomserver/input/consumer.go
+++ b/src/github.com/matrix-org/dendrite/roomserver/input/consumer.go
@@ -47,6 +47,7 @@ type Consumer struct {
 	ErrorLogger ErrorLogger
 }
 
+// WriteOutputRoomEvent implements OutputRoomEventWriter
 func (c *Consumer) WriteOutputRoomEvent(output api.OutputRoomEvent) error {
 	var m sarama.ProducerMessage
 	value, err := json.Marshal(output)
diff --git a/src/github.com/matrix-org/dendrite/roomserver/input/events.go b/src/github.com/matrix-org/dendrite/roomserver/input/events.go
index f2cdc2304..f1b3b6431 100644
--- a/src/github.com/matrix-org/dendrite/roomserver/input/events.go
+++ b/src/github.com/matrix-org/dendrite/roomserver/input/events.go
@@ -40,7 +40,9 @@ type RoomEventDatabase interface {
 	GetLatestEventsForUpdate(roomNID types.RoomNID) ([]types.StateAtEventAndReference, string, types.RoomRecentEventsUpdater, error)
 }
 
+// OutputRoomEventWriter has the APIs needed to write an event to the output logs.
 type OutputRoomEventWriter interface {
+	// Write an event.
 	WriteOutputRoomEvent(output api.OutputRoomEvent) error
 }