diff --git a/tantri/cli/__init__.py b/tantri/cli/__init__.py
index 3b0d73b..210f7c6 100755
--- a/tantri/cli/__init__.py
+++ b/tantri/cli/__init__.py
@@ -39,6 +39,8 @@ def _set_up_logging(filename):
 @click.option("--log-file", help="A filename to use for logging (implies --log)")
 @click.version_option(tantri.get_version())
 def cli(log, log_file):
+	"""Utilities for generating simulated TLS time series data.
+	"""
 	if log or (log_file is not None):
 		# log file has been provided, let's log
 		_set_up_logging(log_file)