diff --git a/packages/opencode/test/bus/bus.test.ts b/packages/opencode/test/bus/bus.test.ts
index 876cb1ed74..0844986162 100644
--- a/packages/opencode/test/bus/bus.test.ts
+++ b/packages/opencode/test/bus/bus.test.ts
@@ -1,220 +1,240 @@
-import { afterEach, describe, expect, test } from "bun:test"
-import { Schema } from "effect"
+import { afterEach, describe, expect } from "bun:test"
+import { CrossSpawnSpawner } from "@opencode-ai/core/cross-spawn-spawner"
+import { Deferred, Effect, Layer, Schema } from "effect"
 import { Bus } from "../../src/bus"
 import { BusEvent } from "../../src/bus/bus-event"
-import { Instance } from "../../src/project/instance"
-import { WithInstance } from "../../src/project/with-instance"
-import { disposeAllInstances, tmpdir } from "../fixture/fixture"
+import { disposeAllInstances, provideInstance, tmpdirScoped } from "../fixture/fixture"
+import { testEffect } from "../lib/effect"
 
 const TestEvent = {
   Ping: BusEvent.define("test.ping", Schema.Struct({ value: Schema.Number })),
   Pong: BusEvent.define("test.pong", Schema.Struct({ message: Schema.String })),
 }
 
-function withInstance(directory: string, fn: () => Promise<void>) {
-  return WithInstance.provide({ directory, fn })
-}
+const it = testEffect(Layer.mergeAll(Bus.layer, CrossSpawnSpawner.defaultLayer))
 
 describe("Bus", () => {
   afterEach(() => disposeAllInstances())
 
   describe("publish + subscribe", () => {
-    test("subscriber is live immediately after subscribe returns", async () => {
-      await using tmp = await tmpdir()
-      const received: number[] = []
+    it.instance("subscriber is live immediately after subscribe returns", () =>
+      Effect.gen(function* () {
+        const bus = yield* Bus.Service
+        const received: number[] = []
+        const done = yield* Deferred.make<void>()
 
-      await withInstance(tmp.path, async () => {
-        Bus.subscribe(TestEvent.Ping, (evt) => {
+        yield* bus.subscribeCallback(TestEvent.Ping, (evt) => {
           received.push(evt.properties.value)
+          Deferred.doneUnsafe(done, Effect.void)
         })
-        await Bus.publish(TestEvent.Ping, { value: 42 })
-        await Bun.sleep(10)
-      })
+        yield* bus.publish(TestEvent.Ping, { value: 42 })
+        yield* Deferred.await(done).pipe(Effect.timeout("2 seconds"))
 
-      expect(received).toEqual([42])
-    })
+        expect(received).toEqual([42])
+      }),
+    )
 
-    test("subscriber receives matching events", async () => {
-      await using tmp = await tmpdir()
-      const received: number[] = []
+    it.instance("subscriber receives matching events", () =>
+      Effect.gen(function* () {
+        const bus = yield* Bus.Service
+        const received: number[] = []
+        const done = yield* Deferred.make<void>()
 
-      await withInstance(tmp.path, async () => {
-        Bus.subscribe(TestEvent.Ping, (evt) => {
+        yield* bus.subscribeCallback(TestEvent.Ping, (evt) => {
           received.push(evt.properties.value)
+          if (received.length === 2) Deferred.doneUnsafe(done, Effect.void)
         })
-        // Give the subscriber fiber time to start consuming
-        await Bun.sleep(10)
-        await Bus.publish(TestEvent.Ping, { value: 42 })
-        await Bus.publish(TestEvent.Ping, { value: 99 })
-        // Give subscriber time to process
-        await Bun.sleep(10)
-      })
+        yield* bus.publish(TestEvent.Ping, { value: 42 })
+        yield* bus.publish(TestEvent.Ping, { value: 99 })
+        yield* Deferred.await(done).pipe(Effect.timeout("2 seconds"))
 
-      expect(received).toEqual([42, 99])
-    })
+        expect(received).toEqual([42, 99])
+      }),
+    )
 
-    test("subscriber does not receive events of other types", async () => {
-      await using tmp = await tmpdir()
-      const pings: number[] = []
+    it.instance("subscriber does not receive events of other types", () =>
+      Effect.gen(function* () {
+        const bus = yield* Bus.Service
+        const pings: number[] = []
+        const done = yield* Deferred.make<void>()
 
-      await withInstance(tmp.path, async () => {
-        Bus.subscribe(TestEvent.Ping, (evt) => {
+        yield* bus.subscribeCallback(TestEvent.Ping, (evt) => {
           pings.push(evt.properties.value)
+          Deferred.doneUnsafe(done, Effect.void)
         })
-        await Bun.sleep(10)
-        await Bus.publish(TestEvent.Pong, { message: "hello" })
-        await Bus.publish(TestEvent.Ping, { value: 1 })
-        await Bun.sleep(10)
-      })
+        yield* bus.publish(TestEvent.Pong, { message: "hello" })
+        yield* bus.publish(TestEvent.Ping, { value: 1 })
+        yield* Deferred.await(done).pipe(Effect.timeout("2 seconds"))
 
-      expect(pings).toEqual([1])
-    })
+        expect(pings).toEqual([1])
+      }),
+    )
 
-    test("publish with no subscribers does not throw", async () => {
-      await using tmp = await tmpdir()
-
-      await withInstance(tmp.path, async () => {
-        await Bus.publish(TestEvent.Ping, { value: 1 })
-      })
-    })
+    it.instance("publish with no subscribers does not throw", () =>
+      Effect.gen(function* () {
+        const bus = yield* Bus.Service
+        yield* bus.publish(TestEvent.Ping, { value: 1 })
+      }),
+    )
   })
 
   describe("unsubscribe", () => {
-    test("unsubscribe stops delivery", async () => {
-      await using tmp = await tmpdir()
-      const received: number[] = []
+    it.instance("unsubscribe stops delivery", () =>
+      Effect.gen(function* () {
+        const bus = yield* Bus.Service
+        const received: number[] = []
+        const first = yield* Deferred.make<void>()
 
-      await withInstance(tmp.path, async () => {
-        const unsub = Bus.subscribe(TestEvent.Ping, (evt) => {
+        const unsub = yield* bus.subscribeCallback(TestEvent.Ping, (evt) => {
           received.push(evt.properties.value)
+          if (evt.properties.value === 1) Deferred.doneUnsafe(first, Effect.void)
         })
-        await Bun.sleep(10)
-        await Bus.publish(TestEvent.Ping, { value: 1 })
-        await Bun.sleep(10)
-        unsub()
-        await Bun.sleep(10)
-        await Bus.publish(TestEvent.Ping, { value: 2 })
-        await Bun.sleep(10)
-      })
+        yield* bus.publish(TestEvent.Ping, { value: 1 })
+        yield* Deferred.await(first).pipe(Effect.timeout("2 seconds"))
+        yield* Effect.sync(unsub)
+        yield* bus.publish(TestEvent.Ping, { value: 2 })
+        yield* Effect.sleep("10 millis")
 
-      expect(received).toEqual([1])
-    })
+        expect(received).toEqual([1])
+      }),
+    )
   })
 
   describe("subscribeAll", () => {
-    test("subscribeAll is live immediately after subscribe returns", async () => {
-      await using tmp = await tmpdir()
-      const received: string[] = []
+    it.instance("subscribeAll is live immediately after subscribe returns", () =>
+      Effect.gen(function* () {
+        const bus = yield* Bus.Service
+        const received: string[] = []
+        const done = yield* Deferred.make<void>()
 
-      await withInstance(tmp.path, async () => {
-        Bus.subscribeAll((evt) => {
+        yield* bus.subscribeAllCallback((evt) => {
           received.push(evt.type)
+          Deferred.doneUnsafe(done, Effect.void)
         })
-        await Bus.publish(TestEvent.Ping, { value: 1 })
-        await Bun.sleep(10)
-      })
+        yield* bus.publish(TestEvent.Ping, { value: 1 })
+        yield* Deferred.await(done).pipe(Effect.timeout("2 seconds"))
 
-      expect(received).toEqual(["test.ping"])
-    })
+        expect(received).toEqual(["test.ping"])
+      }),
+    )
 
-    test("receives all event types", async () => {
-      await using tmp = await tmpdir()
-      const received: string[] = []
+    it.instance("receives all event types", () =>
+      Effect.gen(function* () {
+        const bus = yield* Bus.Service
+        const received: string[] = []
+        const done = yield* Deferred.make<void>()
 
-      await withInstance(tmp.path, async () => {
-        Bus.subscribeAll((evt) => {
+        yield* bus.subscribeAllCallback((evt) => {
           received.push(evt.type)
+          if (received.length === 2) Deferred.doneUnsafe(done, Effect.void)
         })
-        await Bun.sleep(10)
-        await Bus.publish(TestEvent.Ping, { value: 1 })
-        await Bus.publish(TestEvent.Pong, { message: "hi" })
-        await Bun.sleep(10)
-      })
+        yield* bus.publish(TestEvent.Ping, { value: 1 })
+        yield* bus.publish(TestEvent.Pong, { message: "hi" })
+        yield* Deferred.await(done).pipe(Effect.timeout("2 seconds"))
 
-      expect(received).toContain("test.ping")
-      expect(received).toContain("test.pong")
-    })
+        expect(received).toContain("test.ping")
+        expect(received).toContain("test.pong")
+      }),
+    )
   })
 
   describe("multiple subscribers", () => {
-    test("all subscribers for same event type are called", async () => {
-      await using tmp = await tmpdir()
-      const a: number[] = []
-      const b: number[] = []
+    it.instance("all subscribers for same event type are called", () =>
+      Effect.gen(function* () {
+        const bus = yield* Bus.Service
+        const a: number[] = []
+        const b: number[] = []
+        const doneA = yield* Deferred.make<void>()
+        const doneB = yield* Deferred.make<void>()
 
-      await withInstance(tmp.path, async () => {
-        Bus.subscribe(TestEvent.Ping, (evt) => {
+        yield* bus.subscribeCallback(TestEvent.Ping, (evt) => {
           a.push(evt.properties.value)
+          Deferred.doneUnsafe(doneA, Effect.void)
         })
-        Bus.subscribe(TestEvent.Ping, (evt) => {
+        yield* bus.subscribeCallback(TestEvent.Ping, (evt) => {
           b.push(evt.properties.value)
+          Deferred.doneUnsafe(doneB, Effect.void)
         })
-        await Bun.sleep(10)
-        await Bus.publish(TestEvent.Ping, { value: 7 })
-        await Bun.sleep(10)
-      })
+        yield* bus.publish(TestEvent.Ping, { value: 7 })
+        yield* Deferred.await(doneA).pipe(Effect.timeout("2 seconds"))
+        yield* Deferred.await(doneB).pipe(Effect.timeout("2 seconds"))
 
-      expect(a).toEqual([7])
-      expect(b).toEqual([7])
-    })
+        expect(a).toEqual([7])
+        expect(b).toEqual([7])
+      }),
+    )
   })
 
   describe("instance isolation", () => {
-    test("events in one directory do not reach subscribers in another", async () => {
-      await using tmpA = await tmpdir()
-      await using tmpB = await tmpdir()
-      const receivedA: number[] = []
-      const receivedB: number[] = []
+    it.live("events in one directory do not reach subscribers in another", () =>
+      Effect.gen(function* () {
+        const tmpA = yield* tmpdirScoped()
+        const tmpB = yield* tmpdirScoped()
+        const receivedA: number[] = []
+        const receivedB: number[] = []
+        const doneA = yield* Deferred.make<void>()
+        const doneB = yield* Deferred.make<void>()
 
-      await withInstance(tmpA.path, async () => {
-        Bus.subscribe(TestEvent.Ping, (evt) => {
-          receivedA.push(evt.properties.value)
-        })
-        await Bun.sleep(10)
-      })
+        yield* Effect.gen(function* () {
+          const bus = yield* Bus.Service
+          yield* bus.subscribeCallback(TestEvent.Ping, (evt) => {
+            receivedA.push(evt.properties.value)
+            Deferred.doneUnsafe(doneA, Effect.void)
+          })
+        }).pipe(provideInstance(tmpA))
 
-      await withInstance(tmpB.path, async () => {
-        Bus.subscribe(TestEvent.Ping, (evt) => {
-          receivedB.push(evt.properties.value)
-        })
-        await Bun.sleep(10)
-      })
+        yield* Effect.gen(function* () {
+          const bus = yield* Bus.Service
+          yield* bus.subscribeCallback(TestEvent.Ping, (evt) => {
+            receivedB.push(evt.properties.value)
+            Deferred.doneUnsafe(doneB, Effect.void)
+          })
+        }).pipe(provideInstance(tmpB))
 
-      await withInstance(tmpA.path, async () => {
-        await Bus.publish(TestEvent.Ping, { value: 1 })
-        await Bun.sleep(10)
-      })
+        yield* Effect.gen(function* () {
+          const bus = yield* Bus.Service
+          yield* bus.publish(TestEvent.Ping, { value: 1 })
+        }).pipe(provideInstance(tmpA))
 
-      await withInstance(tmpB.path, async () => {
-        await Bus.publish(TestEvent.Ping, { value: 2 })
-        await Bun.sleep(10)
-      })
+        yield* Effect.gen(function* () {
+          const bus = yield* Bus.Service
+          yield* bus.publish(TestEvent.Ping, { value: 2 })
+        }).pipe(provideInstance(tmpB))
 
-      expect(receivedA).toEqual([1])
-      expect(receivedB).toEqual([2])
-    })
+        yield* Deferred.await(doneA).pipe(Effect.timeout("2 seconds"))
+        yield* Deferred.await(doneB).pipe(Effect.timeout("2 seconds"))
+
+        expect(receivedA).toEqual([1])
+        expect(receivedB).toEqual([2])
+      }),
+    )
   })
 
   describe("instance disposal", () => {
-    test("InstanceDisposed is delivered to wildcard subscribers before stream ends", async () => {
-      await using tmp = await tmpdir()
-      const received: string[] = []
+    it.live("InstanceDisposed is delivered to wildcard subscribers before stream ends", () =>
+      Effect.gen(function* () {
+        const tmp = yield* tmpdirScoped()
+        const received: string[] = []
+        const seen = yield* Deferred.make<void>()
+        const disposed = yield* Deferred.make<void>()
 
-      await withInstance(tmp.path, async () => {
-        Bus.subscribeAll((evt) => {
-          received.push(evt.type)
-        })
-        await Bun.sleep(10)
-        await Bus.publish(TestEvent.Ping, { value: 1 })
-        await Bun.sleep(10)
-      })
+        yield* Effect.gen(function* () {
+          const bus = yield* Bus.Service
+          yield* bus.subscribeAllCallback((evt) => {
+            received.push(evt.type)
+            if (evt.type === TestEvent.Ping.type) Deferred.doneUnsafe(seen, Effect.void)
+            if (evt.type === Bus.InstanceDisposed.type) Deferred.doneUnsafe(disposed, Effect.void)
+          })
+          yield* bus.publish(TestEvent.Ping, { value: 1 })
+          yield* Deferred.await(seen).pipe(Effect.timeout("2 seconds"))
+        }).pipe(provideInstance(tmp))
 
-      // disposeAllInstances triggers the finalizer which publishes InstanceDisposed
-      await disposeAllInstances()
-      await Bun.sleep(50)
+        yield* Effect.promise(disposeAllInstances)
+        yield* Deferred.await(disposed).pipe(Effect.timeout("2 seconds"))
 
-      expect(received).toContain("test.ping")
-      expect(received).toContain(Bus.InstanceDisposed.type)
-    })
+        expect(received).toContain("test.ping")
+        expect(received).toContain(Bus.InstanceDisposed.type)
+      }),
+    )
   })
 })