diff --git a/packages/core/src/context.ts b/packages/core/src/context.ts
index 835f213..e9d9fd2 100644
--- a/packages/core/src/context.ts
+++ b/packages/core/src/context.ts
@@ -121,11 +121,9 @@ export class Context {
       if (!internal) {
         checkInject(name)
         return Reflect.get(target, name, ctx)
-      }
-
-      if (internal.type === 'accessor') {
+      } else if (internal.type === 'accessor') {
         return internal.get.call(ctx)
-      } else if (internal.type === 'service') {
+      } else {
         if (!internal.builtin) checkInject(name)
         return ctx.get(name)
       }
@@ -139,38 +137,11 @@ export class Context {
       if (internal.type === 'accessor') {
         if (!internal.set) return false
         return internal.set.call(ctx, value)
+      } else {
+        ctx.emit('internal/warning', new Error(`Assigning to service ${name} is not recommended, please use \`ctx.set()\` method instead`))
+        ctx.set(name, value)
+        return true
       }
-
-      // service
-      const key = ctx[symbols.isolate][name]
-      const oldValue = ctx.root[key]
-      if (oldValue === value) return true
-
-      // check override
-      if (value && oldValue) {
-        throw new Error(`service ${name} has been registered`)
-      }
-      if (value) {
-        ctx.on('dispose', () => ctx[name] = undefined)
-      }
-      if (isUnproxyable(value)) {
-        ctx.emit('internal/warning', new Error(`service ${name} is an unproxyable object, which may lead to unexpected behavior`))
-      }
-
-      // setup filter for events
-      const self = Object.create(null)
-      self[symbols.filter] = (ctx2: Context) => {
-        // TypeScript is not smart enough to infer the type of `name` here
-        return ctx[symbols.isolate][name as string] === ctx2[symbols.isolate][name as string]
-      }
-
-      ctx.root.emit(self, 'internal/before-service', name, value)
-      ctx.root[key] = value
-      if (value instanceof Object) {
-        defineProperty(value, symbols.origin, ctx)
-      }
-      ctx.root.emit(self, 'internal/service', name, oldValue)
-      return true
     },
   }
 
@@ -253,6 +224,39 @@ export class Context {
     return createTraceable(this, value)
   }
 
+  set(name: string, value: any) {
+    this.provide(name)
+    const key = this[symbols.isolate][name]
+    const oldValue = this.root[key]
+    value ??= undefined
+    if (oldValue === value) return
+
+    // check override
+    if (!isNullable(value) && !isNullable(oldValue)) {
+      throw new Error(`service ${name} has been registered`)
+    }
+    const ctx: Context = this
+    if (!isNullable(value)) {
+      ctx.on('dispose', () => ctx.set(name, undefined))
+    }
+    if (isUnproxyable(value)) {
+      ctx.emit('internal/warning', new Error(`service ${name} is an unproxyable object, which may lead to unexpected behavior`))
+    }
+
+    // setup filter for events
+    const self = Object.create(null)
+    self[symbols.filter] = (ctx2: Context) => {
+      return ctx[symbols.isolate][name] === ctx2[symbols.isolate][name]
+    }
+
+    ctx.emit(self, 'internal/before-service', name, value)
+    ctx.root[key] = value
+    if (value instanceof Object) {
+      defineProperty(value, symbols.origin, ctx)
+    }
+    ctx.emit(self, 'internal/service', name, oldValue)
+  }
+
   provide(name: string, value?: any, builtin?: boolean) {
     const internal = Context.ensureInternal.call(this.root)
     if (name in internal) return
diff --git a/packages/core/src/scope.ts b/packages/core/src/scope.ts
index 35e7fa2..59ddbaf 100644
--- a/packages/core/src/scope.ts
+++ b/packages/core/src/scope.ts
@@ -386,7 +386,7 @@ export class MainScope<C extends Context = Context> extends EffectScope<C> {
       const instance = new this.plugin(context, config)
       const name = instance[Context.expose]
       if (name) {
-        context[name] = instance
+        context.set(name, instance)
       }
       if (instance['fork']) {
         this.forkables.push(instance['fork'].bind(instance))
diff --git a/packages/core/src/service.ts b/packages/core/src/service.ts
index 165aa78..de97331 100644
--- a/packages/core/src/service.ts
+++ b/packages/core/src/service.ts
@@ -56,14 +56,14 @@ export abstract class Service<T = unknown, C extends Context = Context> {
     self.ctx.runtime.name = name
     if (immediate) {
       if (_ctx) self[symbols.expose] = name
-      else self.ctx[name] = self
+      else self.ctx.set(name, self)
     }
 
     self.ctx.on('ready', async () => {
       // await until next tick because derived class has not been initialized yet
       await Promise.resolve()
       await self.start()
-      if (!immediate) self.ctx[name!] = self
+      if (!immediate) self.ctx.set(name!, self)
     })
 
     self.ctx.on('dispose', () => self.stop())