diff --git a/packages/extension-query/src/QueryClient.ts b/packages/extension-query/src/QueryClient.ts
new file mode 100644
index 0000000..bf33a5a
--- /dev/null
+++ b/packages/extension-query/src/QueryClient.ts
@@ -0,0 +1,20 @@
+import { Context, Effect, Layer } from "effect"
+
+
+interface MyService<T> {
+    readonly value: T
+}
+
+const MyServiceAnyTag = Context.GenericTag<MyService<any>>("MyService")
+const MyServiceStringTag = Context.GenericTag<MyService<string>>("MyService")
+
+declare const MyServiceAnyLayer: Layer.Layer<Context.Tag.Service<typeof MyServiceAnyTag>>
+declare const MyServiceStringLayer: Layer.Layer<Context.Tag.Service<typeof MyServiceStringTag>>
+
+
+const prg = Effect.gen(function*() {
+    yield* MyServiceAnyTag
+    yield* MyServiceStringTag
+}).pipe(
+    Effect.provide(MyServiceStringLayer)
+)