diff --git a/packages/core/src/transport/protocol.ts b/packages/core/src/transport/protocol.ts
index 26bb41e..b5e039c 100644
--- a/packages/core/src/transport/protocol.ts
+++ b/packages/core/src/transport/protocol.ts
@@ -4,11 +4,11 @@
 import * as S from '../gen/sturdy.js';
 import { Oid } from '../gen/protocol.js';
 import { Ref } from '../runtime/actor.js';
-import { Decoder, DecoderState, Encoder, EncoderState, GenericEmbedded, neverEmbeddedType, EmbeddedType, Value } from '@preserves/core';
+import { Decoder, DecoderState, Encoder, EncoderState, GenericEmbedded, neverEmbeddedType, EmbeddedType, Value, EmbeddedWriter } from '@preserves/core';
 
 export type WireSymbol = { oid: Oid, ref: Ref, count: number };
 
-export const wireRefEmbeddedType: EmbeddedType<S.WireRef> = {
+export const wireRefEmbeddedType: EmbeddedType<S.WireRef> & EmbeddedWriter<S.WireRef> = {
     decode(s: DecoderState): S.WireRef {
         return S.asWireRef(new Decoder<any>(s).next());
     },