diff --git a/src/_zkapauthorizer/config.py b/src/_zkapauthorizer/config.py
index f91dc3512fe742b5589844acef668291b18c29ff..7ee454aad7151c6608c9ba1b321f4c29ec6e6542 100644
--- a/src/_zkapauthorizer/config.py
+++ b/src/_zkapauthorizer/config.py
@@ -12,6 +12,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+"""
+Helpers for reading values from the Tahoe-LAFS configuration.
+"""
+
 from datetime import timedelta
 from isodate import parse_duration