diff --git a/packages/extension-query/src/MutationRunner.ts b/packages/extension-query/src/MutationRunner.ts
index 3f943c5..323c344 100644
--- a/packages/extension-query/src/MutationRunner.ts
+++ b/packages/extension-query/src/MutationRunner.ts
@@ -1,12 +1,14 @@
 import * as AsyncData from "@typed/async-data"
-import { type Context, Effect, Ref, SubscriptionRef } from "effect"
+import { type Context, Effect, type Fiber, Ref, SubscriptionRef } from "effect"
 import type * as QueryClient from "./QueryClient.js"
 
 
 export interface MutationRunner<K extends readonly unknown[], A, E, R> {
     readonly context: Context.Context<R>
     readonly stateRef: SubscriptionRef.SubscriptionRef<AsyncData.AsyncData<A, E>>
+
     readonly mutate: (...key: K) => Effect.Effect<A, E>
+    readonly forkMutate: (...key: K) => Effect.Effect<Fiber.RuntimeFiber<A, E>>
 }
 
 
@@ -40,9 +42,13 @@ export const make = <EH, K extends readonly unknown[], A, E, HandledE, R>(
         Effect.provide(context),
     )
 
+    const forkMutate = (...key: K) => Effect.forkDaemon(mutate(...key))
+
     return {
         context,
         stateRef,
+
         mutate,
+        forkMutate,
     }
 })
diff --git a/packages/extension-query/src/MutationService.ts b/packages/extension-query/src/MutationService.ts
new file mode 100644
index 0000000..e366571
--- /dev/null
+++ b/packages/extension-query/src/MutationService.ts
@@ -0,0 +1,13 @@
+import type * as AsyncData from "@typed/async-data"
+import { Effect, type Fiber, type SubscriptionRef } from "effect"
+
+
+export interface MutationService<K extends readonly unknown[], A, E> {
+    readonly state: SubscriptionRef.SubscriptionRef<AsyncData.AsyncData<A, E>>
+    readonly mutate: (...key: K) => Effect.Effect<A, E>
+    readonly forkMutate: (...key: K) => Effect.Effect<Fiber.RuntimeFiber<A, E>>
+}
+
+export const Tag = <const Id extends string>(id: Id) => <
+    Self, K extends readonly unknown[], A, E = never,
+>() => Effect.Tag(id)<Self, MutationService<K, A, E>>()
diff --git a/packages/extension-query/src/QueryExtension.ts b/packages/extension-query/src/QueryExtension.ts
index 4deeebb..0fa0b87 100644
--- a/packages/extension-query/src/QueryExtension.ts
+++ b/packages/extension-query/src/QueryExtension.ts
@@ -3,6 +3,7 @@ import { type Cause, type Context, Effect, type Fiber, Layer, type Option, type
 import * as React from "react"
 import { ReffuseExtension, type ReffuseHelpers } from "reffuse"
 import * as MutationRunner from "./MutationRunner.js"
+import type * as MutationService from "./MutationService.js"
 import * as QueryClient from "./QueryClient.js"
 import * as QueryRunner from "./QueryRunner.js"
 import type * as QueryService from "./QueryService.js"
@@ -31,10 +32,12 @@ export interface UseMutationProps<K extends readonly unknown[], A, E, R> {
 
 export interface UseMutationResult<K extends readonly unknown[], A, E> {
     readonly state: SubscriptionRef.SubscriptionRef<AsyncData.AsyncData<A, E>>
+    readonly mutate: (...key: K) => Effect.Effect<A, E>
+    readonly forkMutate: (...key: K) => Effect.Effect<Fiber.RuntimeFiber<A, E>>
 
-    // readonly layer: <Self, Id extends string>(
-    //     tag: Context.TagClass<Self, Id, QueryService.QueryService<K, A, E>>
-    // ) => Layer.Layer<Self>
+    readonly layer: <Self, Id extends string>(
+        tag: Context.TagClass<Self, Id, MutationService.MutationService<K, A, E>>
+    ) => Layer.Layer<Self>
 }
 
 
@@ -96,12 +99,14 @@ export const QueryExtension = ReffuseExtension.make(() => ({
 
         return React.useMemo(() => ({
             state: runner.stateRef,
+            mutate: runner.mutate,
+            forkMutate: runner.forkMutate,
 
-            // layer: tag => Layer.succeed(tag, {
-            //     latestKey: runner.latestKeyRef,
-            //     state: runner.stateRef,
-            //     refresh: runner.forkRefresh,
-            // }),
+            layer: tag => Layer.succeed(tag, {
+                state: runner.stateRef,
+                mutate: runner.mutate,
+                forkMutate: runner.forkMutate,
+            }),
         }), [runner])
     },
 }))
diff --git a/packages/extension-query/src/index.ts b/packages/extension-query/src/index.ts
index 6f603b6..e249d09 100644
--- a/packages/extension-query/src/index.ts
+++ b/packages/extension-query/src/index.ts
@@ -1,5 +1,6 @@
 export * as ErrorHandler from "./ErrorHandler.js"
 export * as MutationRunner from "./MutationRunner.js"
+export * as MutationService from "./MutationService.js"
 export * as QueryClient from "./QueryClient.js"
 export * from "./QueryExtension.js"
 export * as QueryRunner from "./QueryRunner.js"