diff --git a/cmd/aaisp_exporter/README.md b/cmd/aaisp_exporter/README.md
index b32a617..6bbee6f 100644
--- a/cmd/aaisp_exporter/README.md
+++ b/cmd/aaisp_exporter/README.md
@@ -8,3 +8,7 @@ It exposes metrics:
 * **aaisp_broadband_quota_total**: The line's monthly quota in bytes, excluding rollover
 * **aaisp_broadband_rx_rate**: The line's receive (upload) rate in bits per second
 * **aaisp_broadband_tx_rate**: The line's transmit (download) rate in bits per second
+
+To run the service you must export environment variables `CHAOS_CONTROL_LOGIN` and `CHAOS_CONTROL_PASSWORD` using the login details you use for https://control.aa.net.uk/.
+
+The service takess a `-listen` flag for setting the address and port the service binds to. The default is `:8080`.