diff --git a/broker/broker.go b/broker/broker.go
index aaeab1d..e8900ea 100644
--- a/broker/broker.go
+++ b/broker/broker.go
@@ -210,7 +210,7 @@ func main() {
 	flag.StringVar(&geoipDatabase, "geoipdb", "/usr/share/tor/geoip", "path to correctly formatted geoip database mapping IPv4 address ranges to country codes")
 	flag.StringVar(&geoip6Database, "geoip6db", "/usr/share/tor/geoip6", "path to correctly formatted geoip database mapping IPv6 address ranges to country codes")
 	flag.StringVar(&bridgeListFilePath, "bridge-list-path", "", "file path for bridgeListFile")
-	flag.StringVar(&allowedRelayPattern, "allowed-relay-pattern", "", "allowed pattern for relay host name")
+	flag.StringVar(&allowedRelayPattern, "allowed-relay-pattern", "", "allowed pattern for relay host name. The broker will reject proxies whose AcceptedRelayPattern is more restrictive than this")
 	flag.StringVar(&presumedPatternForLegacyClient, "default-relay-pattern", "", "presumed pattern for legacy client")
 	flag.StringVar(&brokerSQSQueueName, "broker-sqs-name", "", "name of broker SQS queue to listen for incoming messages on")
 	flag.StringVar(&brokerSQSQueueRegion, "broker-sqs-region", "", "name of AWS region of broker SQS queue")