diff --git a/birdvisu/annotations/analysis.py b/birdvisu/annotations/analysis.py
index ad63bd1..134f1a8 100644
--- a/birdvisu/annotations/analysis.py
+++ b/birdvisu/annotations/analysis.py
@@ -1,3 +1,8 @@
+"""Analysis annotators
+
+The annotators provided here are mostly concerned about the graph properties of
+the topologies."""
+
 from . import Annotator, Annotation
 from ..topo_v3 import MetricType
 import heapq