diff --git a/packages/annotations/src/store/actions.js b/packages/annotations/src/store/actions.js
index 00c9fa589732a..e6f1e5b409dd0 100644
--- a/packages/annotations/src/store/actions.js
+++ b/packages/annotations/src/store/actions.js
@@ -3,6 +3,13 @@
  */
 import { v4 as uuid } from 'uuid';
 
+/**
+ * @typedef WPAnnotationRange
+ *
+ * @property {number} start The offset where the annotation should start.
+ * @property {number} end   The offset where the annotation should end.
+ */
+
 /**
  * Adds an annotation to a block.
  *
@@ -13,15 +20,13 @@ import { v4 as uuid } from 'uuid';
  *
  * The `range` property is only relevant if the selector is 'range'.
  *
- * @param {Object} annotation                    The annotation to add.
- * @param {string} annotation.blockClientId      The blockClientId to add the annotation to.
- * @param {string} annotation.richTextIdentifier Identifier for the RichText instance the annotation applies to.
- * @param {Object} annotation.range              The range at which to apply this annotation.
- * @param {number} annotation.range.start        The offset where the annotation should start.
- * @param {number} annotation.range.end          The offset where the annotation should end.
- * @param {string} annotation.[selector="range"] The way to apply this annotation.
- * @param {string} annotation.[source="default"] The source that added the annotation.
- * @param {string} annotation.[id]               The ID the annotation should have. Generates a UUID by default.
+ * @param {Object}            annotation                    The annotation to add.
+ * @param {string}            annotation.blockClientId      The blockClientId to add the annotation to.
+ * @param {string}            annotation.richTextIdentifier Identifier for the RichText instance the annotation applies to.
+ * @param {WPAnnotationRange} annotation.range              The range at which to apply this annotation.
+ * @param {string}            [annotation.selector="range"] The way to apply this annotation.
+ * @param {string}            [annotation.source="default"] The source that added the annotation.
+ * @param {string}            [annotation.id]               The ID the annotation should have. Generates a UUID by default.
  *
  * @return {Object} Action object.
  */