diff --git a/src/effect/schema/class/MutableTaggedClass.ts b/src/effect/schema/class/MutableTaggedClass.ts
index b4c3e0e..201441f 100644
--- a/src/effect/schema/class/MutableTaggedClass.ts
+++ b/src/effect/schema/class/MutableTaggedClass.ts
@@ -1,21 +1,25 @@
 import { Schema as S } from "@effect/schema"
-import type { Annotations, Struct } from "@effect/schema/Schema"
-import type { TMutableClass } from "./TMutableClass"
+import type { Annotations, PropertySignature, Struct } from "@effect/schema/Schema"
 import type { HasFields } from "./util"
 
 
-export function MutableClass<Self>(identifier: string) {
-    return <Fields extends Struct.Fields>(
+export function MutableTaggedClass<Self>(identifier?: string) {
+    return <
+        Tag    extends string,
+        Fields extends Struct.Fields,
+    >(
+        tag:           Tag,
         fieldsOr:      Fields | HasFields<Fields>,
         annotations?:  Annotations.Schema<Self>,
     ) =>
-        S.Class<Self>(identifier)(fieldsOr, annotations) as TMutableClass<
+        // S.TaggedClass<Self>(identifier)(tag, fieldsOr, annotations) as S.TaggedClass<
+        //     Self,
+        //     Tag,
+        //     { readonly _tag: PropertySignature<":", Tag, never, ":", Tag, true, never> } & Fields
+        // >
+        S.TaggedClass<Self>(identifier)(tag, fieldsOr, annotations) as S.TaggedClass<
             Self,
-            Fields,
-            Struct.Encoded<Fields>,
-            Struct.Context<Fields>,
-            Struct.Constructor<Fields>,
-            {},
-            {}
+            Tag,
+            { readonly _tag: PropertySignature<":", Tag, never, ":", Tag, true, never> } & Fields
         >
 }