diff --git a/dp3/snapshots/snapshooter.py b/dp3/snapshots/snapshooter.py
index a4986d81..e7965caf 100644
--- a/dp3/snapshots/snapshooter.py
+++ b/dp3/snapshots/snapshooter.py
@@ -201,9 +201,9 @@ def register_correlation_hook(
         `entity_type` and attribute specifications are validated, `ValueError` is raised on failure.
 
         Args:
-            hook: `hook` callable should expect entity type as str
-                and its current values, including linked entities, as dict;
-                and its master record as dict.
+            hook: `hook` callable should expect three parameters:
+                entity_type (str), current_values (dict, including linked entities),
+                and master_record (dict).
                 Can optionally return a list of DataPointTask objects to perform.
             entity_type: specifies entity type
             depends_on: each item should specify an attribute that is depended on