diff --git a/src/kv/commonKeyValueDB.ts b/src/kv/commonKeyValueDB.ts
index c0c157a..ce6d22e 100644
--- a/src/kv/commonKeyValueDB.ts
+++ b/src/kv/commonKeyValueDB.ts
@@ -50,5 +50,12 @@ export interface CommonKeyValueDB {
 
   count: (table: string) => Promise<number>
 
+  /**
+   *
+   * Increments the value of a key in a table by a given amount.
+   * Default increment is 1 when `by` is not provided.
+   *
+   * Returns the new value.
+   */
   increment: (table: string, id: string, by?: number) => Promise<number>
 }
diff --git a/src/kv/commonKeyValueDao.ts b/src/kv/commonKeyValueDao.ts
index 545fb09..8757b2c 100644
--- a/src/kv/commonKeyValueDao.ts
+++ b/src/kv/commonKeyValueDao.ts
@@ -253,6 +253,12 @@ export class CommonKeyValueDao<T> {
     )
   }
 
+  /**
+   * Increments the `id` field by the amount specified in `by`,
+   * or by 1 if `by` is not specified.
+   *
+   * Returns the new value of the field.
+   */
   async increment(id: string, by = 1): Promise<number> {
     return await this.cfg.db.increment(this.cfg.table, id, by)
   }