diff --git a/frontend/src/contracts/voice.ts b/frontend/src/contracts/voice.ts
index 07c8ad1..730d98e 100644
--- a/frontend/src/contracts/voice.ts
+++ b/frontend/src/contracts/voice.ts
@@ -17,6 +17,18 @@ export type VoiceStreamEndCommand = WsRequest<'voice.stream.end', VoiceStreamEnd
 
 export type VoiceStreamError = WsFailure<'voice.stream.error'>;
 
+export type VoiceStreamCancelPayload = {
+  stream_id: string;
+  job_id: string | null;
+};
+
+export type VoiceStreamCancelCommand = WsRequest<'voice.stream.cancel', VoiceStreamCancelPayload>;
+
+export type VoiceStreamCancelAck =
+  | WsSuccess<'voice.stream.cancelled', { stream_id: string }>
+  | VoiceStreamError
+  | WsFailure<'voice.stream.cancel'>;
+
 export type VoiceStreamStarted = WsSuccess<
   'voice.stream.started',
   { stream_id: string; job_id: string }
diff --git a/frontend/src/dev/fakes/FakeWsServer.ts b/frontend/src/dev/fakes/FakeWsServer.ts
index 1b0d82e..5512e7c 100644
--- a/frontend/src/dev/fakes/FakeWsServer.ts
+++ b/frontend/src/dev/fakes/FakeWsServer.ts
@@ -13,6 +13,7 @@ import type {
   SessionHello,
   SessionReady,
   VoiceParseResultMessage,
+  VoiceStreamCancelCommand,
   VoiceStreamEndCommand,
   VoiceStreamStartCommand,
   VoiceStreamStartResponse,