diff --git a/packages/core/src/context.ts b/packages/core/src/context.ts
index ca5f24e..c305d18 100644
--- a/packages/core/src/context.ts
+++ b/packages/core/src/context.ts
@@ -56,7 +56,7 @@ export interface Context {
 
 export class Context {
   static readonly invoke = Symbol.for('cordis.invoke')
-  static readonly config = Symbol.for('cordis.config')
+  static readonly extend = Symbol.for('cordis.extend')
   static readonly events = Symbol.for('cordis.events')
   static readonly static = Symbol.for('cordis.static')
   static readonly filter = Symbol.for('cordis.filter')
@@ -66,20 +66,20 @@ export class Context {
   static readonly internal = Symbol.for('cordis.internal')
   static readonly intercept = Symbol.for('cordis.intercept')
 
-  static createProxy(ctx: any, value: any) {
+  static createTraceable(ctx: any, value: any) {
     const proxy = new Proxy(value, {
       get: (target, name, receiver) => {
         if (name === Context.current || name === 'caller') return ctx
         return Reflect.get(target, name, receiver)
       },
       apply: (target, thisArg, args) => {
-        return Context.applyProxy(proxy, target, thisArg, args)
+        return Context.applyTraceable(proxy, target, thisArg, args)
       },
     })
     return proxy
   }
 
-  static applyProxy(proxy: any, value: any, thisArg: any, args: any[]) {
+  static applyTraceable(proxy: any, value: any, thisArg: any, args: any[]) {
     if (!value[Context.invoke]) return Reflect.apply(value, thisArg, args)
     return value[Context.invoke].apply(proxy, args)
   }
@@ -274,7 +274,7 @@ export class Context {
       defineProperty(value, Context.current, this)
       return value
     }
-    return Context.createProxy(this, value)
+    return Context.createTraceable(this, value)
   }
 
   provide(name: string, value?: any, builtin?: boolean) {
diff --git a/packages/core/src/scope.ts b/packages/core/src/scope.ts
index 7d3d48d..779912a 100644
--- a/packages/core/src/scope.ts
+++ b/packages/core/src/scope.ts
@@ -332,7 +332,7 @@ export class MainScope<C extends Context = Context> extends EffectScope<C> {
     super(registry[Context.current] as C, config)
     registry.set(plugin, this)
     if (!plugin) {
-      this.name = 'app'
+      this.name = 'root'
       this.isActive = true
     } else {
       this.setup()
diff --git a/packages/core/src/service.ts b/packages/core/src/service.ts
index b6cab98..170e634 100644
--- a/packages/core/src/service.ts
+++ b/packages/core/src/service.ts
@@ -5,20 +5,28 @@ export namespace Service {
   export interface Options {
     name?: string
     immediate?: boolean
-    standalone?: boolean
   }
 }
 
-function makeFunctional(proto: {}) {
+function makeCallableProto(proto: {}) {
   if (proto === Object.prototype) return Function.prototype
-  const result = Object.create(makeFunctional(Object.getPrototypeOf(proto)))
+  const result = Object.create(makeCallableProto(Object.getPrototypeOf(proto)))
   for (const key of Reflect.ownKeys(proto)) {
     Object.defineProperty(result, key, Object.getOwnPropertyDescriptor(proto, key)!)
   }
   return result
 }
 
-export abstract class Service<C extends Context = Context> {
+function makeCallable(ctx: Context, name: string, proto: {}) {
+  const self = function (...args: any[]) {
+    const proxy = Context.createTraceable(ctx, self)
+    return Context.applyTraceable(proxy, self, this, args)
+  }
+  defineProperty(self, 'name', name)
+  return Object.setPrototypeOf(self, proto)
+}
+
+export abstract class Service<C extends Context = Context, T = unknown> {
   static immediate = false
   static Context = Context
 
@@ -29,24 +37,20 @@ export abstract class Service<C extends Context = Context> {
   protected ctx!: C
   protected [Context.current]!: C
 
-  constructor(ctx: C | undefined, public readonly name: string, options?: boolean | Service.Options) {
+  constructor(ctx: C | undefined, public readonly name: string, options?: boolean) {
     let self = this
     if (self[Context.invoke]) {
-      // functional service
-      self = function (...args: any[]) {
-        const proxy = Context.createProxy(ctx, self)
-        return Context.applyProxy(proxy, self, this, args)
-      } as any
-      defineProperty(self, 'name', name)
-      Object.setPrototypeOf(self, makeFunctional(Object.getPrototypeOf(this)))
+      // FIXME ctx!
+      self = makeCallable(ctx!, name, makeCallableProto(Object.getPrototypeOf(this)))
     }
 
     self.ctx = ctx ?? new (self.constructor as any).Context()
-    self.ctx.provide(name)
     defineProperty(self, Context.current, ctx)
 
     const resolved = typeof options === 'boolean' ? { immediate: options } : options ?? {}
-    if (!resolved.standalone && resolved.immediate) {
+    if (resolved.immediate) {
+      self.ctx.provide(name)
+      self.ctx.runtime.name = name
       if (ctx) self[Context.expose] = name
       else self.ctx[name] = self
     }
@@ -55,7 +59,7 @@ export abstract class Service<C extends Context = Context> {
       // await until next tick because derived class has not been initialized yet
       await Promise.resolve()
       await self.start()
-      if (!resolved.standalone && !resolved.immediate) self.ctx[name] = self
+      if (!resolved.immediate) self.ctx[name] = self
     })
 
     self.ctx.on('dispose', () => self.stop())
@@ -66,6 +70,18 @@ export abstract class Service<C extends Context = Context> {
     return ctx[Context.shadow][this.name] === this.ctx[Context.shadow][this.name]
   }
 
+  [Context.extend](props?: any) {
+    const caller = this[Context.current]
+    let self: typeof this
+    if (this[Context.invoke]) {
+      self = makeCallable(caller, this.name, this)
+    } else {
+      self = Object.create(this)
+    }
+    defineProperty(self, Context.current, caller)
+    return Context.associate(Object.assign(self, props), this.name)
+  }
+
   static [Symbol.hasInstance](instance: any) {
     let constructor = instance.constructor
     while (constructor) {
diff --git a/packages/core/tests/service.spec.ts b/packages/core/tests/service.spec.ts
index e41dad2..82a18a8 100644
--- a/packages/core/tests/service.spec.ts
+++ b/packages/core/tests/service.spec.ts
@@ -282,8 +282,8 @@ describe('Service', () => {
     }
 
     class Foo extends Service {
-      constructor(ctx: Context, public config?: Config, standalone?: boolean) {
-        super(ctx, 'foo', { immediate: true, standalone })
+      constructor(ctx: Context, public config?: Config) {
+        super(ctx, 'foo', true)
       }
 
       [Context.invoke](init?: Config) {
@@ -304,7 +304,9 @@ describe('Service', () => {
       }
 
       extend(config?: Config) {
-        return new Foo(this[Context.current], { ...this.config, ...config }, true)
+        return this[Context.extend]({
+          config: { ...this.config, ...config },
+        })
       }
     }