diff --git a/packages/extension-query/src/QueryExtension.ts b/packages/extension-query/src/QueryExtension.ts
index 79c0a89..1a55d78 100644
--- a/packages/extension-query/src/QueryExtension.ts
+++ b/packages/extension-query/src/QueryExtension.ts
@@ -6,6 +6,13 @@ import * as QueryRunner from "./QueryRunner.js"
 import type * as QueryService from "./QueryService.js"
 
 
+export interface QueryExtension<GlobalE> {
+    useQuery<K extends readonly unknown[], A, E, R>(
+        this: ReffuseHelpers.ReffuseHelpers<R>,
+        props: UseQueryProps<K, A, E, R>,
+    ): UseQueryResult<K, A, Exclude<E, GlobalE>>
+}
+
 export interface UseQueryProps<K extends readonly unknown[], A, E, R> {
     readonly key: Stream.Stream<K>
     readonly query: (key: K) => Effect.Effect<A, E, R>