diff --git a/packages/core/README.md b/packages/core/README.md
index cddabaa..83beaf0 100644
--- a/packages/core/README.md
+++ b/packages/core/README.md
@@ -484,7 +484,7 @@ class ListService extends Service {
   addItem(item) {
     this.data.push(item)
     // return a dispose function
-    return this[Context.current].collect('list-item', () => {
+    return this.ctx.collect('list-item', () => {
       return this.removeItem(item)
     })
   }
@@ -506,7 +506,7 @@ class ListService extends Service {
 - The `addItem` method adds an item to the list and returns a dispose function which can be used to remove the item from the list. When the caller context is disposed, the disposable function will be automatically called.
 - The `removeItem` method removes an item from the list and returns a boolean value indicating whether the item is successfully removed.
 
-In the above example, `addItem` is implemented as disposable via `this[Context.current].collect()`. `caller` is a special property which always points to the last context which access the service. `ctx.collect()` accepts two parameters: the first is the name of disposable, the second is the callback function.
+In the above example, `addItem` is implemented as disposable via `this.ctx.collect()`. `caller` is a special property which always points to the last context which access the service. `ctx.collect()` accepts two parameters: the first is the name of disposable, the second is the callback function.
 
 #### Service isolation [↑](#contents)
 
diff --git a/packages/core/src/reflect.ts b/packages/core/src/reflect.ts
index 144eff0..a4bcd7f 100644
--- a/packages/core/src/reflect.ts
+++ b/packages/core/src/reflect.ts
@@ -31,7 +31,7 @@ export default class ReflectService {
       if (typeof prop !== 'string') return Reflect.get(target, prop, ctx)
 
       if (Reflect.has(target, prop)) {
-        return getTraceable(ctx, Reflect.get(target, prop, ctx))
+        return getTraceable(ctx, Reflect.get(target, prop, ctx), true)
       }
 
       const checkInject = (name: string) => {
@@ -142,6 +142,10 @@ export default class ReflectService {
     internal[name] = { type: 'service', builtin }
     this.ctx.root[key] = value
     this.ctx.root[symbols.isolate][name] = key
+    isObject(value) && defineProperty(value, symbols.tracker, {
+      associate: name,
+      property: 'ctx',
+    })
   }
 
   accessor(name: string, options: Omit<Context.Internal.Accessor, 'type'>) {
diff --git a/packages/core/src/registry.ts b/packages/core/src/registry.ts
index 40f6da5..dff1c90 100644
--- a/packages/core/src/registry.ts
+++ b/packages/core/src/registry.ts
@@ -146,18 +146,14 @@ export default class Registry<C extends Context = Context> {
   plugin(plugin: Plugin<C>, config?: any) {
     // check if it's a valid plugin
     this.resolve(plugin, true)
-
-    // magic: this.ctx[symbols.trace] === this
-    // Here we ignore the reference
-    const ctx: C = this.ctx === this.ctx.root ? this.ctx : Object.getPrototypeOf(this.ctx)
-    ctx.scope.assertActive()
+    this.ctx.scope.assertActive()
 
     // resolve plugin config
     let error: any
     try {
       config = resolveConfig(plugin, config)
     } catch (reason) {
-      this.context.emit(ctx, 'internal/error', reason)
+      this.context.emit(this.ctx, 'internal/error', reason)
       error = reason
       config = null
     }
@@ -166,13 +162,13 @@ export default class Registry<C extends Context = Context> {
     let runtime = this.get(plugin)
     if (runtime) {
       if (!runtime.isForkable) {
-        this.context.emit(ctx, 'internal/warning', new Error(`duplicate plugin detected: ${plugin.name}`))
+        this.context.emit(this.ctx, 'internal/warning', new Error(`duplicate plugin detected: ${plugin.name}`))
       }
-      return runtime.fork(ctx, config, error)
+      return runtime.fork(this.ctx, config, error)
     }
 
-    runtime = new MainScope(ctx, plugin, config, error)
+    runtime = new MainScope(this.ctx, plugin, config, error)
     this.set(plugin, runtime)
-    return runtime.fork(ctx, config, error)
+    return runtime.fork(this.ctx, config, error)
   }
 }
diff --git a/packages/core/src/service.ts b/packages/core/src/service.ts
index 5b82b37..9720ab6 100644
--- a/packages/core/src/service.ts
+++ b/packages/core/src/service.ts
@@ -95,6 +95,8 @@ export abstract class Service<T = unknown, C extends Context = Context> {
   static [Symbol.hasInstance](instance: any) {
     let constructor = instance.constructor
     while (constructor) {
+      // constructor may be a proxy
+      constructor = constructor.prototype?.constructor
       if (constructor === this) return true
       constructor = Object.getPrototypeOf(constructor)
     }
diff --git a/packages/core/src/utils.ts b/packages/core/src/utils.ts
index 3170d12..116b3f1 100644
--- a/packages/core/src/utils.ts
+++ b/packages/core/src/utils.ts
@@ -64,43 +64,65 @@ export function isObject(value: any): value is {} {
   return value && (typeof value === 'object' || typeof value === 'function')
 }
 
-function isTraceable(value: any): value is {} {
-  return isObject(value) && !isUnproxyable(value) && symbols.tracker in value
+export function getTraceable<T>(ctx: Context, value: T, noTrap?: boolean): T {
+  const tracker = value?.[symbols.tracker]
+  if (!tracker) return value
+  return createTraceable(ctx, value, tracker, noTrap)
 }
 
-export function getTraceable<T>(ctx: Context, value: T): T {
-  if (isTraceable(value)) {
-    return createTraceable(ctx, value, value[symbols.tracker])
-  } else {
-    return value
-  }
+function createTrapMethod(ctx: Context, value: any, property: string) {
+  return new Proxy(value, {
+    apply: (target, thisArg, args) => {
+      return getTraceable(ctx, Reflect.apply(target, new Proxy(thisArg, {
+        get: (target, prop, receiver) => {
+          if (prop === property) {
+            // FIXME Can I use target[prop]?
+            const origin = Reflect.getOwnPropertyDescriptor(target, prop)?.value
+            return ctx.extend({ [symbols.source]: origin })
+          }
+          return Reflect.get(target, prop, receiver)
+        },
+        set: (target, prop, value, receiver) => {
+          if (prop === property) return false
+          return Reflect.set(target, prop, value, receiver)
+        },
+      }), args))
+    },
+  })
 }
 
-function createTraceable(ctx: Context, value: any, tracer: Tracker) {
+function createTraceable(ctx: Context, value: any, tracker: Tracker, noTrap?: boolean) {
+  if (ctx[symbols.source]) {
+    ctx = Object.getPrototypeOf(ctx)
+  }
   const proxy = new Proxy(value, {
     get: (target, prop, receiver) => {
+      if (prop === tracker.property) return ctx
       if (typeof prop === 'symbol') {
         return Reflect.get(target, prop, receiver)
       }
-      if (prop === tracer.property) {
-        const origin = Reflect.getOwnPropertyDescriptor(target, tracer.property)?.value
-        return ctx.extend({ [symbols.source]: origin })
+      if (tracker.associate && ctx[symbols.internal][`${tracker.associate}.${prop}`]) {
+        return Reflect.get(ctx, `${tracker.associate}.${prop}`)
       }
-      if (!tracer.associate || !ctx[symbols.internal][`${tracer.associate}.${prop}`]) {
-        return getTraceable(ctx, Reflect.get(target, prop, receiver))
+      const value = Reflect.get(target, prop, receiver)
+      const innerTracker = value?.[symbols.tracker]
+      if (innerTracker) {
+        return createTraceable(ctx, value, innerTracker)
+      } else if (!noTrap && tracker.property && typeof value === 'function') {
+        return createTrapMethod(ctx, value, tracker.property)
+      } else {
+        return value
       }
-      return ctx[`${tracer.associate}.${prop}`]
     },
     set: (target, prop, value, receiver) => {
-      if (prop === tracer.property) return false
+      if (prop === tracker.property) return false
       if (typeof prop === 'symbol') {
         return Reflect.set(target, prop, value, receiver)
       }
-      if (!tracer.associate || !ctx[symbols.internal][`${tracer.associate}.${prop}`]) {
-        return Reflect.set(target, prop, value, receiver)
+      if (tracker.associate && ctx[symbols.internal][`${tracker.associate}.${prop}`]) {
+        return Reflect.set(ctx, `${tracker.associate}.${prop}`, value)
       }
-      ctx[`${tracer.associate}.${prop}`] = value
-      return true
+      return Reflect.set(target, prop, value, receiver)
     },
     apply: (target, thisArg, args) => {
       return applyTraceable(proxy, target, thisArg, args)
diff --git a/packages/core/tests/associate.spec.ts b/packages/core/tests/associate.spec.ts
index 5f7319e..adf6caa 100644
--- a/packages/core/tests/associate.spec.ts
+++ b/packages/core/tests/associate.spec.ts
@@ -1,6 +1,6 @@
 import { Context, Service } from '../src'
 import { expect } from 'chai'
-import {} from './utils'
+import { checkError } from './utils'
 
 describe('Association', () => {
   it('service injection', async () => {
@@ -61,7 +61,7 @@ describe('Association', () => {
         associate: 'session',
       }
 
-      constructor(private ctx: Context) {}
+      constructor(public ctx: Context) {}
     }
 
     class Foo extends Service {
@@ -70,7 +70,7 @@ describe('Association', () => {
       }
 
       createSession() {
-        return this.ctx.reflect.trace(new Session(this.ctx))
+        return new Session(this.ctx)
       }
     }
 
@@ -79,22 +79,36 @@ describe('Association', () => {
     }
 
     class Bar extends Service {
+      inject = ['foo']
+
       constructor(ctx: Context) {
         super(ctx, 'bar', true)
-        ctx.set('session.bar', function (this: Session) {
-          return this
+        ctx.mixin('bar', {
+          getBar: 'session.bar',
         })
       }
+
+      getBar(this: Session) {
+        return this
+      }
     }
 
     const root = new Context()
-
     root.plugin(Foo)
-    const session = root.foo.createSession()
-    expect(session).to.be.instanceof(Session)
-    expect(session.bar).to.be.undefined
 
-    root.plugin(Bar)
-    expect(session.bar()).to.be.instanceof(Session)
+    root.inject(['foo'], (ctx) => {
+      const session = ctx.foo.createSession()
+      expect(session).to.be.instanceof(Session)
+      expect(session.bar).to.be.undefined
+
+      ctx.plugin(Bar)
+      ctx.inject(['bar'], (ctx) => {
+        const session = ctx.foo.createSession()
+        expect(session).to.be.instanceof(Session)
+        expect(session.bar()).to.be.instanceof(Bar)
+      })
+    })
+
+    await checkError(root)
   })
 })
diff --git a/packages/core/tests/invoke.spec.ts b/packages/core/tests/invoke.spec.ts
index 8a0a359..7604f15 100644
--- a/packages/core/tests/invoke.spec.ts
+++ b/packages/core/tests/invoke.spec.ts
@@ -27,7 +27,7 @@ describe('functional service', () => {
         return result
       }
 
-      reflect() {
+      invoke() {
         return this()
       }
 
@@ -54,9 +54,9 @@ describe('functional service', () => {
     expect(foo2()).to.deep.equal({ a: 1, c: 3 })
     const foo3 = foo1.extend({ d: 4 })
     expect(foo3).to.be.instanceof(Foo)
-    expect(foo3.reflect()).to.deep.equal({ a: 1, b: 2, d: 4 })
+    expect(foo3.invoke()).to.deep.equal({ a: 1, b: 2, d: 4 })
 
-    // context tracibility
-    expect(foo1.reflect()).to.deep.equal({ a: 1, b: 2 })
+    // context traceability
+    expect(foo1.invoke()).to.deep.equal({ a: 1, b: 2 })
   })
 })
diff --git a/packages/core/tests/service.spec.ts b/packages/core/tests/service.spec.ts
index 4ab931f..298841c 100644
--- a/packages/core/tests/service.spec.ts
+++ b/packages/core/tests/service.spec.ts
@@ -128,7 +128,7 @@ describe('Service', () => {
     expect(callback.mock.calls).to.have.length(1)
   })
 
-  it('traceable effect (inject)', async () => {
+  it('traceable effect (with inject)', async () => {
     class Foo extends Service {
       static inject = ['counter']
 
@@ -161,6 +161,40 @@ describe('Service', () => {
     expect(warning.mock.calls).to.have.length(0)
   })
 
+  it('traceable effect (without inject)', async () => {
+    class Foo extends Service {
+      constructor(ctx: Context) {
+        super(ctx, 'foo', true)
+      }
+
+      count() {
+        this.ctx.counter.increse()
+        return this.ctx.counter.value
+      }
+    }
+
+    const root = new Context()
+    const warning = mock.fn()
+    root.on('internal/warning', warning)
+    root.set('counter', new Counter(root))
+
+    root.plugin(Foo)
+    expect(root.foo.count()).to.equal(1)
+    expect(root.foo.count()).to.equal(2)
+    expect(warning.mock.calls).to.have.length(0) // access from root
+
+    const fork = root.inject(['foo'], (ctx) => {
+      expect(ctx.foo.count()).to.equal(3)
+      expect(ctx.foo.count()).to.equal(4)
+      expect(warning.mock.calls).to.have.length(4)
+    })
+
+    fork.dispose()
+    expect(root.foo.count()).to.equal(3)
+
+    await checkError(root)
+  })
+
   it('dependency update', async () => {
     const callback = mock.fn((foo: any) => {})
     const dispose = mock.fn((foo: any) => {})