diff --git a/tracers.ts/src/tracers/array-tracer.ts b/tracers.ts/src/tracers/array-tracer.ts
index f705f13..fc348e0 100644
--- a/tracers.ts/src/tracers/array-tracer.ts
+++ b/tracers.ts/src/tracers/array-tracer.ts
@@ -7,10 +7,9 @@ interface ArrayTracerCreateOptions<T extends JsonValue> {
   walker?: (builder: { add: (item: T) => void }) => void;
 }
 
-type ArrayTracerMetadata = {
-  // initial: JsonValue[];
+interface ArrayTracerMetadata {
   length: number;
-};
+}
 
 export const createArrayTracer = <T extends JsonValue = JsonValue>(
   options: ArrayTracerCreateOptions<T>,