diff --git a/packages/effect-fc/src/Mutation.ts b/packages/effect-fc/src/Mutation.ts
new file mode 100644
index 0000000..69de1a4
--- /dev/null
+++ b/packages/effect-fc/src/Mutation.ts
@@ -0,0 +1,124 @@
+import { type Context, Effect, Equal, type Fiber, Option, Pipeable, Predicate, type Scope, Stream, type Subscribable, SubscriptionRef } from "effect"
+import * as Result from "./Result.js"
+
+
+export const MutationTypeId: unique symbol = Symbol.for("@effect-fc/Mutation/Mutation")
+export type MutationTypeId = typeof MutationTypeId
+
+export interface Mutation<in out K extends readonly any[], in out A, in out E = never, in out R = never, in out P = never>
+extends Pipeable.Pipeable {
+    readonly [MutationTypeId]: MutationTypeId
+
+    readonly context: Context.Context<Scope.Scope | R>
+    readonly f: (key: K) => Effect.Effect<A, E, R>
+    readonly initialProgress: P
+
+    readonly latestKey: Subscribable.Subscribable<Option.Option<K>>
+    readonly fiber: Subscribable.Subscribable<Option.Option<Fiber.Fiber<A, E>>>
+    readonly result: Subscribable.Subscribable<Result.Result<A, E, P>>
+
+    mutate(key: K): Effect.Effect<Result.Result<A, E, P>>
+    mutateSubscribable(key: K): Effect.Effect<Subscribable.Subscribable<Result.Result<A, E, P>>>
+}
+
+export class MutationImpl<in out K extends readonly any[], in out A, in out E = never, in out R = never, in out P = never>
+extends Pipeable.Class() implements Mutation<K, A, E, R, P> {
+    readonly [MutationTypeId]: MutationTypeId = MutationTypeId
+
+    constructor(
+        readonly context: Context.Context<Scope.Scope | NoInfer<R>>,
+        readonly f: (key: K) => Effect.Effect<A, E, R>,
+        readonly initialProgress: P,
+
+        readonly latestKey: SubscriptionRef.SubscriptionRef<Option.Option<K>>,
+        readonly fiber: SubscriptionRef.SubscriptionRef<Option.Option<Fiber.Fiber<A, E>>>,
+        readonly result: SubscriptionRef.SubscriptionRef<Result.Result<A, E, P>>,
+    ) {
+        super()
+    }
+
+    mutate(key: K): Effect.Effect<Result.Result<A, E, P>> {
+        return SubscriptionRef.set(this.latestKey, Option.some(key)).pipe(
+            Effect.andThen(Effect.provide(this.start(key), this.context)),
+            Effect.andThen(sub => this.watch(sub)),
+        )
+    }
+
+    mutateSubscribable(key: K): Effect.Effect<Subscribable.Subscribable<Result.Result<A, E, P>>> {
+        return Effect.andThen(
+            SubscriptionRef.set(this.latestKey, Option.some(key)),
+            Effect.provide(this.start(key), this.context)
+        )
+    }
+
+    start(key: K): Effect.Effect<
+        Subscribable.Subscribable<Result.Result<A, E, P>>,
+        never,
+        Scope.Scope | R
+    > {
+        return this.result.pipe(
+            Effect.map(previous => (Result.isSuccess(previous) || Result.isFailure(previous))
+                ? previous
+                : undefined
+            ),
+            Effect.andThen(previous => Result.unsafeForkEffect(
+                Effect.onExit(this.f(key), () => Effect.andThen(
+                    Effect.all([Effect.fiberId, this.fiber]),
+                    ([currentFiberId, fiber]) => Option.match(fiber, {
+                        onSome: v => Equal.equals(currentFiberId, v.id())
+                            ? SubscriptionRef.set(this.fiber, Option.none())
+                            : Effect.void,
+                        onNone: () => Effect.void,
+                    })
+                )),
+
+                {
+                    initialProgress: this.initialProgress,
+                    previous,
+                } as Result.unsafeForkEffect.Options<A, E, P>,
+            )),
+            Effect.tap(([, fiber]) => SubscriptionRef.set(this.fiber, Option.some(fiber))),
+            Effect.map(([sub]) => sub),
+        )
+    }
+
+    watch(
+        sub: Subscribable.Subscribable<Result.Result<A, E, P>>
+    ): Effect.Effect<Result.Result<A, E, P>> {
+        return Effect.andThen(
+            sub.get,
+            initial => Stream.runFoldEffect(
+                Stream.filter(sub.changes, Predicate.not(Result.isInitial)),
+                initial,
+                (_, result) => Effect.as(SubscriptionRef.set(this.result, result), result),
+            ),
+        )
+    }
+}
+
+export const isMutation = (u: unknown): u is Mutation<unknown[], unknown, unknown, unknown, unknown> => Predicate.hasProperty(u, MutationTypeId)
+
+export declare namespace make {
+    export interface Options<K extends readonly any[], A, E = never, R = never, P = never> {
+        readonly f: (key: NoInfer<K>) => Effect.Effect<A, E, Result.forkEffect.InputContext<R, NoInfer<P>>>
+        readonly initialProgress?: P
+    }
+}
+
+export const make = Effect.fnUntraced(function* <K extends readonly any[], A, E = never, R = never, P = never>(
+    options: make.Options<K, A, E, R, P>
+): Effect.fn.Return<
+    Mutation<K, A, E, Result.forkEffect.OutputContext<A, E, R, P>, P>,
+    never,
+    Scope.Scope | Result.forkEffect.OutputContext<A, E, R, P>
+> {
+    return new MutationImpl(
+        yield* Effect.context<Scope.Scope | Result.forkEffect.OutputContext<A, E, R, P>>(),
+        options.f as any,
+        options.initialProgress as P,
+
+        yield* SubscriptionRef.make(Option.none<K>()),
+        yield* SubscriptionRef.make(Option.none<Fiber.Fiber<A, E>>()),
+        yield* SubscriptionRef.make(Result.initial<A, E, P>()),
+    )
+})
diff --git a/packages/effect-fc/src/Query.ts b/packages/effect-fc/src/Query.ts
index 159198e..0ad366e 100644
--- a/packages/effect-fc/src/Query.ts
+++ b/packages/effect-fc/src/Query.ts
@@ -5,10 +5,11 @@ import * as Result from "./Result.js"
 export const QueryTypeId: unique symbol = Symbol.for("@effect-fc/Query/Query")
 export type QueryTypeId = typeof QueryTypeId
 
-export interface Query<in out K extends readonly any[], in out A, in out E = never, out R = never, in out P = never>
+export interface Query<in out K extends readonly any[], in out A, in out E = never, in out R = never, in out P = never>
 extends Pipeable.Pipeable {
     readonly [QueryTypeId]: QueryTypeId
 
+    readonly context: Context.Context<Scope.Scope | R>
     readonly key: Stream.Stream<K>
     readonly f: (key: K) => Effect.Effect<A, E, R>
     readonly initialProgress: P
@@ -22,11 +23,12 @@ extends Pipeable.Pipeable {
     readonly refresh: Effect.Effect<Result.Result<A, E, P>, Cause.NoSuchElementException>
 }
 
-class QueryImpl<in out K extends readonly any[], in out A, in out E = never, in out R = never, in out P = never>
+export class QueryImpl<in out K extends readonly any[], in out A, in out E = never, in out R = never, in out P = never>
 extends Pipeable.Class() implements Query<K, A, E, R, P> {
     readonly [QueryTypeId]: QueryTypeId = QueryTypeId
 
     constructor(
+        readonly context: Context.Context<Scope.Scope | NoInfer<R>>,
         readonly key: Stream.Stream<K>,
         readonly f: (key: K) => Effect.Effect<A, E, R>,
         readonly initialProgress: P,
@@ -34,8 +36,6 @@ extends Pipeable.Class() implements Query<K, A, E, R, P> {
         readonly latestKey: SubscriptionRef.SubscriptionRef<Option.Option<K>>,
         readonly fiber: SubscriptionRef.SubscriptionRef<Option.Option<Fiber.Fiber<A, E>>>,
         readonly result: SubscriptionRef.SubscriptionRef<Result.Result<A, E, P>>,
-
-        readonly context: Context.Context<Scope.Scope | NoInfer<R>>,
     ) {
         super()
     }
@@ -83,15 +83,15 @@ extends Pipeable.Class() implements Query<K, A, E, R, P> {
     > {
         return this.result.pipe(
             Effect.map(previous => (Result.isSuccess(previous) || Result.isFailure(previous))
-                ? Option.some(previous)
-                : Option.none()
+                ? previous
+                : undefined
             ),
             Effect.andThen(previous => Result.unsafeForkEffect(
                 Effect.onExit(this.f(key), () => SubscriptionRef.set(this.fiber, Option.none())),
                 {
                     initialProgress: this.initialProgress,
-                    refresh: refresh && Option.isSome(previous),
-                    previous: Option.getOrUndefined(previous),
+                    refresh: refresh && previous,
+                    previous,
                 } as Result.unsafeForkEffect.Options<A, E, P>,
             )),
             Effect.tap(([, fiber]) => SubscriptionRef.set(this.fiber, Option.some(fiber))),
@@ -131,6 +131,7 @@ export const make = Effect.fnUntraced(function* <K extends readonly any[], A, E
     Scope.Scope | Result.forkEffect.OutputContext<A, E, R, P>
 > {
     return new QueryImpl(
+        yield* Effect.context<Scope.Scope | Result.forkEffect.OutputContext<A, E, R, P>>(),
         options.key,
         options.f as any,
         options.initialProgress as P,
@@ -138,8 +139,6 @@ export const make = Effect.fnUntraced(function* <K extends readonly any[], A, E
         yield* SubscriptionRef.make(Option.none<K>()),
         yield* SubscriptionRef.make(Option.none<Fiber.Fiber<A, E>>()),
         yield* SubscriptionRef.make(Result.initial<A, E, P>()),
-
-        yield* Effect.context<Scope.Scope | Result.forkEffect.OutputContext<A, E, R, P>>(),
     )
 })
 
diff --git a/packages/effect-fc/src/index.ts b/packages/effect-fc/src/index.ts
index 18468a4..2167ff9 100644
--- a/packages/effect-fc/src/index.ts
+++ b/packages/effect-fc/src/index.ts
@@ -3,6 +3,7 @@ export * as Component from "./Component.js"
 export * as ErrorObserver from "./ErrorObserver.js"
 export * as Form from "./Form.js"
 export * as Memoized from "./Memoized.js"
+export * as Mutation from "./Mutation.js"
 export * as PropertyPath from "./PropertyPath.js"
 export * as PubSub from "./PubSub.js"
 export * as Query from "./Query.js"