diff --git a/packages/opencode/specs/effect-migration.md b/packages/opencode/specs/effect-migration.md
index 4f195917fde..86eb156d6e9 100644
--- a/packages/opencode/specs/effect-migration.md
+++ b/packages/opencode/specs/effect-migration.md
@@ -123,6 +123,7 @@ Done now:
 - [x] `Discovery`
 - [x] `File`
 - [x] `Snapshot`
+- [x] `SessionStatus`
 
 Still open and likely worth migrating:
 
diff --git a/packages/opencode/src/effect/instances.ts b/packages/opencode/src/effect/instances.ts
index 6fcfddb24f5..408b55bedc9 100644
--- a/packages/opencode/src/effect/instances.ts
+++ b/packages/opencode/src/effect/instances.ts
@@ -8,6 +8,7 @@ import { Instance } from "@/project/instance"
 import { Vcs } from "@/project/vcs"
 import { ProviderAuth } from "@/provider/auth-service"
 import { Question } from "@/question/service"
+import { SessionStatus } from "@/session/status"
 import { Skill } from "@/skill/service"
 import { Snapshot } from "@/snapshot/service"
 import { InstanceContext } from "./instance-context"
@@ -24,6 +25,7 @@ export type InstanceServices =
   | FileTime.Service
   | Format.Service
   | File.Service
+  | SessionStatus.Service
   | Skill.Service
   | Snapshot.Service
 
@@ -44,6 +46,7 @@ function lookup(_key: string) {
     FileTime.layer,
     Format.layer,
     File.layer,
+    SessionStatus.layer,
     Skill.defaultLayer,
     Snapshot.defaultLayer,
   ).pipe(Layer.provide(ctx))
diff --git a/packages/opencode/src/effect/runtime.ts b/packages/opencode/src/effect/runtime.ts
index e6f1f326262..2cbc4b9e7e6 100644
--- a/packages/opencode/src/effect/runtime.ts
+++ b/packages/opencode/src/effect/runtime.ts
@@ -20,6 +20,10 @@ export function runPromiseInstance<A, E>(effect: Effect.Effect<A, E, InstanceSer
   return runtime.runPromise(effect.pipe(Effect.provide(Instances.get(Instance.directory))))
 }
 
+export function runSyncInstance<A, E>(effect: Effect.Effect<A, E, InstanceServices>) {
+  return runtime.runSync(effect.pipe(Effect.provide(Instances.get(Instance.directory))))
+}
+
 export function disposeRuntime() {
   return runtime.dispose()
 }
diff --git a/packages/opencode/src/session/status.ts b/packages/opencode/src/session/status.ts
index 57e7939853a..af0de15670a 100644
--- a/packages/opencode/src/session/status.ts
+++ b/packages/opencode/src/session/status.ts
@@ -1,7 +1,8 @@
 import { BusEvent } from "@/bus/bus-event"
 import { Bus } from "@/bus"
-import { Instance } from "@/project/instance"
+import { runSyncInstance } from "@/effect/runtime"
 import { SessionID } from "./schema"
+import { Effect, Layer, ServiceMap } from "effect"
 import z from "zod"
 
 export namespace SessionStatus {
@@ -42,36 +43,51 @@ export namespace SessionStatus {
     ),
   }
 
-  const state = Instance.state(() => {
-    const data: Record<string, Info> = {}
-    return data
-  })
+  export interface Interface {
+    readonly get: (sessionID: SessionID) => Effect.Effect<Info>
+    readonly list: () => Effect.Effect<Record<string, Info>>
+    readonly set: (sessionID: SessionID, status: Info) => Effect.Effect<void>
+  }
+
+  export class Service extends ServiceMap.Service<Service, Interface>()("@opencode/SessionStatus") {}
+
+  export const layer = Layer.effect(
+    Service,
+    Effect.gen(function* () {
+      const data = new Map<SessionID, Info>()
+
+      const get = Effect.fn("SessionStatus.get")(function* (sessionID: SessionID) {
+        return data.get(sessionID) ?? { type: "idle" as const }
+      })
+
+      const list = Effect.fn("SessionStatus.list")(function* () {
+        return Object.fromEntries(data)
+      })
+
+      const set = Effect.fn("SessionStatus.set")(function* (sessionID: SessionID, status: Info) {
+        Bus.publish(Event.Status, { sessionID, status })
+        if (status.type === "idle") {
+          // deprecated
+          Bus.publish(Event.Idle, { sessionID })
+          data.delete(sessionID)
+          return
+        }
+        data.set(sessionID, status)
+      })
 
-  export function get(sessionID: SessionID) {
-    return (
-      state()[sessionID] ?? {
-        type: "idle",
-      }
-    )
+      return Service.of({ get, list, set })
+    }),
+  )
+
+  export function get(sessionID: SessionID): Info {
+    return runSyncInstance(Service.use((svc) => svc.get(sessionID)))
   }
 
-  export function list() {
-    return state()
+  export function list(): Record<string, Info> {
+    return runSyncInstance(Service.use((svc) => svc.list()))
   }
 
   export function set(sessionID: SessionID, status: Info) {
-    Bus.publish(Event.Status, {
-      sessionID,
-      status,
-    })
-    if (status.type === "idle") {
-      // deprecated
-      Bus.publish(Event.Idle, {
-        sessionID,
-      })
-      delete state()[sessionID]
-      return
-    }
-    state()[sessionID] = status
+    runSyncInstance(Service.use((svc) => svc.set(sessionID, status)))
   }
 }