diff --git a/packages/core/test/session-create.test.ts b/packages/core/test/session-create.test.ts
index 662b45d5c89..11bc3639db3 100644
--- a/packages/core/test/session-create.test.ts
+++ b/packages/core/test/session-create.test.ts
@@ -37,7 +37,7 @@ import { testEffect } from "./lib/effect"
 import { LocationServiceMap } from "@opencode-ai/core/location-service-map"
 import { promptLocationLayer } from "./fixture/prompt-location"
 import { globalProjectLayer } from "./lib/project"
-import { tmpdir } from "./fixture/tmpdir"
+import { tmpdirScoped } from "./fixture/tmpdir"
 
 const it = testEffect(
   AppNodeBuilder.build(
@@ -96,10 +96,7 @@ const assertCreateInputTypes = (session: Session.Interface) => {
 void assertCreateInputTypes
 
 function withTmp<A, E, R>(f: (directory: string) => Effect.Effect<A, E, R>) {
-  return Effect.acquireRelease(
-    Effect.promise(() => tmpdir()),
-    (tmp) => Effect.promise(() => tmp[Symbol.asyncDispose]()),
-  ).pipe(Effect.flatMap((tmp) => f(tmp.path)))
+  return tmpdirScoped().pipe(Effect.flatMap((tmp) => f(tmp.path)))
 }
 
 describe("Session.create", () => {
@@ -967,10 +964,7 @@ describe("Session.create", () => {
         data: event.data,
       }))
 
-      const tmp = yield* Effect.acquireRelease(
-        Effect.promise(() => tmpdir()),
-        (tmp) => Effect.promise(() => tmp[Symbol.asyncDispose]()),
-      )
+      const tmp = yield* tmpdirScoped()
       const targetLayer = AppNodeBuilder.build(
         LayerNode.group([Database.node, Bus.node, SessionProjector.node, SessionStore.node]),
         [
diff --git a/packages/core/test/session-message-update.test.ts b/packages/core/test/session-message-update.test.ts
index 23810107e1d..45e72cb111c 100644
--- a/packages/core/test/session-message-update.test.ts
+++ b/packages/core/test/session-message-update.test.ts
@@ -21,7 +21,7 @@ import { SessionProjector } from "@opencode-ai/core/session/projector"
 import { SessionStore } from "@opencode-ai/core/session/store"
 import { Money } from "@opencode-ai/schema/money"
 import { LayerNode } from "@opencode-ai/util/effect/layer-node"
-import { tmpdir } from "./fixture/tmpdir"
+import { tmpdirScoped } from "./fixture/tmpdir"
 import { testEffect } from "./lib/effect"
 import { globalProjectLayer } from "./lib/project"
 
@@ -149,10 +149,7 @@ describe("Session.updateMessage", () => {
         type: event.type,
         data: event.data,
       }))
-      const tmp = yield* Effect.acquireRelease(
-        Effect.promise(() => tmpdir()),
-        (tmp) => Effect.promise(() => tmp[Symbol.asyncDispose]()),
-      )
+      const tmp = yield* tmpdirScoped()
       const target = AppNodeBuilder.build(
         LayerNode.group([Database.node, Bus.node, SessionProjector.node, SessionStore.node]),
         [
diff --git a/packages/core/test/session-prompt.test.ts b/packages/core/test/session-prompt.test.ts
index a75146300d1..fbc8a86cbaa 100644
--- a/packages/core/test/session-prompt.test.ts
+++ b/packages/core/test/session-prompt.test.ts
@@ -1,7 +1,5 @@
 import { describe, expect } from "bun:test"
 import { DateTime, Effect, Fiber, Layer, LayerMap, Schema, Stream } from "effect"
-import { mkdtemp, rm } from "fs/promises"
-import { tmpdir } from "os"
 import path from "path"
 import { pathToFileURL } from "url"
 import { eq } from "drizzle-orm"
@@ -30,6 +28,7 @@ import { Image } from "@opencode-ai/core/image"
 import { PluginSupervisor } from "@opencode-ai/core/plugin/supervisor"
 import { PluginHooks } from "@opencode-ai/core/plugin/hooks"
 import { Snapshot } from "@opencode-ai/core/snapshot"
+import { tmpdirScoped } from "./fixture/tmpdir"
 import { testEffect } from "./lib/effect"
 
 const executionCalls: Session.ID[] = []
@@ -403,11 +402,8 @@ describe("Session.prompt", () => {
     Effect.gen(function* () {
       yield* setup
       const session = yield* Session.Service
-      const directory = yield* Effect.acquireRelease(
-        Effect.promise(() => mkdtemp(path.join(tmpdir(), "opencode-session-prompt-"))),
-        (directory) => Effect.promise(() => rm(directory, { recursive: true, force: true })),
-      )
-      const source = path.join(directory, "image.png")
+      const directory = yield* tmpdirScoped("opencode-session-prompt-")
+      const source = path.join(directory.path, "image.png")
       const bytes = Buffer.from(
         "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNk+A8AAQUBAScY42YAAAAASUVORK5CYII=",
         "base64",