diff --git a/federationapi/routing/join.go b/federationapi/routing/join.go
index 1476f903f..0dd39277b 100644
--- a/federationapi/routing/join.go
+++ b/federationapi/routing/join.go
@@ -312,6 +312,9 @@ func SendJoin(
 		}
 	}
 
+	// TODO: (PowerDAG) query state & power DAG
+	// We return the entire power DAG with a send_join response
+
 	// Fetch the state and auth chain. We do this before we send the events
 	// on, in case this fails.
 	var stateAndAuthChainResponse api.QueryStateAndAuthChainResponse
@@ -339,6 +342,9 @@ func SendJoin(
 		}
 	}
 
+	// TODO: (Power DAG) will we have enough info in a join response to check membership?
+	// We should include the user membership event (if there is one) in the state response.
+
 	// Check if the user is already in the room. If they're already in then
 	// there isn't much point in sending another join event into the room.
 	// Also check to see if they are banned: if they are then we reject them.
@@ -425,6 +431,8 @@ func SendJoin(
 		}
 	}
 
+	// TODO: (PowerDAG) Adapt this to return the full power DAG & state + user membership event (if it exists)
+
 	// sort events deterministically by depth (lower is earlier)
 	// We also do this because sytest's basic federation server isn't good at using the correct
 	// state if these lists are randomised, resulting in flakey tests. :(