diff --git a/src/effect/EffectSchemaTraitExpressionBuilder.ts b/src/effect/EffectSchemaTraitExpressionBuilder.ts
index 8e8139f..50a4110 100644
--- a/src/effect/EffectSchemaTraitExpressionBuilder.ts
+++ b/src/effect/EffectSchemaTraitExpressionBuilder.ts
@@ -1,5 +1,6 @@
 import { Schema as S } from "@effect/schema"
 import * as Types from "effect/Types"
+import { Simplify } from "type-fest"
 import { Trait, TraitTuple } from "../Trait"
 import { TraitExpression } from "../TraitExpression"
 import { TraitExpressionBuilder } from "../TraitExpressionBuilder"
@@ -40,7 +41,7 @@ export class EffectSchemaInitialTraitExpressionBuilder {
     }
 
     extends<
-        Super     extends S.Class<Self, Fields, I, R, C, Inherited, Proto>,
+        Super     extends StaticMembers<S.Class<Self, Fields, I, R, C, Inherited, Proto>>,
         Self,
         Fields    extends S.Struct.Fields,
         I, R, C,
@@ -49,14 +50,28 @@ export class EffectSchemaInitialTraitExpressionBuilder {
 
         NewFields extends S.Struct.Fields,
     >(
-        superclass:    Super | S.Class<Self, Fields, I, R, C, Inherited, Proto>,
+        superclass:    Super | StaticMembers<S.Class<Self, Fields, I, R, C, Inherited, Proto>>,
         identifier:    string,
         fields:        NewFields,
         annotations?:  S.Annotations.Schema<unknown>,
     ) {
         return new EffectSchemaTraitExpressionBuilder(
-            superclass.extend<unknown>(identifier)(fields, annotations),
-            {} as Omit<StaticMembers<Super>, keyof S.Class<Self, Fields, I, R, C, Inherited, Proto>>,
+            superclass.extend<unknown>(identifier)(fields, annotations) as S.Class<
+                unknown,
+                Fields & NewFields,
+                I & S.Struct.Encoded<NewFields>,
+                R | S.Struct.Context<NewFields>,
+                C & S.Struct.Constructor<NewFields>,
+                Self,
+                Proto
+            >,
+
+            {} as Simplify<
+                Omit<Super,
+                    "prototype" | keyof S.Class<Self, Fields, I, R, C, Inherited, Proto>
+                >
+            >,
+
             [],
         )
     }
diff --git a/src/effect/tests.ts b/src/effect/tests.ts
index 315bf07..a241123 100644
--- a/src/effect/tests.ts
+++ b/src/effect/tests.ts
@@ -24,7 +24,7 @@ type Extr<T> =
         : never
 
 type InspectSchemaClass<T> = T extends S.Class<infer Self, infer Fields, infer I, infer R, infer C, infer Inherited, infer Proto>
-    ? C
+    ? Inherited
     : never
 
 
@@ -38,14 +38,11 @@ const userExp = effectSchemaExpression
     .build()
 
 @userExp.staticImplements
-class User extends userExp.extends<User>() implements Implements<typeof userExp> {
+export class User extends userExp.extends<User>() implements Implements<typeof userExp> {
     aMethodThatShouldBeInherited() {}
     static aStaticMethodThatShouldBeInherited() {}
 }
 
-type T1 = InspectSchemaClass<typeof userExp.superclass>
-type T2 = InstanceType<typeof userExp.superclass>
-
 const user = new User({ id: 0n, role: "User" })
 // user.id = 0n
 
@@ -57,8 +54,10 @@ const adminExp = effectSchemaExpression
     // .immutable()
     .build()
 
+type T = InspectSchemaClass<typeof adminExp.superclass>
+
 @adminExp.staticImplements
-class Admin extends adminExp.extends<Admin>() implements Implements<typeof adminExp> {
+export class Admin extends adminExp.extends<Admin>() implements Implements<typeof adminExp> {
 }
 
 const admin = new Admin({ id: 1n, role: "Admin" })