diff --git a/source/gegl/generic.ts b/source/gegl/generic.ts
index c5f6a60..8341126 100644
--- a/source/gegl/generic.ts
+++ b/source/gegl/generic.ts
@@ -1,6 +1,6 @@
 import {BaseOperation} from './base.js';
 
-export type GenericParameters = Record<string, number | string>;
+export type GenericParameters = Record<string, number | string | boolean>;
 
 export class Generic extends BaseOperation<GenericParameters> {
   public get default() {