diff --git a/index.d.ts b/index.d.ts
index 9472cc1c..35d974eb 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -665,4 +665,4 @@ export type MigrationContext = ClientConfig & {
 /**
  * The shape of the migration function that should be exported.
  */
-export type MigrationFunction = (migration: Migration, context?: MigrationContext) => void
+export type MigrationFunction = (migration: Migration, context: MigrationContext) => void