diff --git a/packages/backend/src/server/api/endpoints/mahjong/cancel-match.ts b/packages/backend/src/server/api/endpoints/mahjong/cancel-match.ts
index 99a2a3078b..dd6f273e01 100644
--- a/packages/backend/src/server/api/endpoints/mahjong/cancel-match.ts
+++ b/packages/backend/src/server/api/endpoints/mahjong/cancel-match.ts
@@ -14,9 +14,6 @@ export const meta = {
 
 	errors: {
 	},
-
-	res: {
-	},
 } as const;
 
 export const paramDef = {
diff --git a/packages/misskey-js/etc/misskey-js.api.md b/packages/misskey-js/etc/misskey-js.api.md
index 78aba72d7e..f2bf3680de 100644
--- a/packages/misskey-js/etc/misskey-js.api.md
+++ b/packages/misskey-js/etc/misskey-js.api.md
@@ -2024,7 +2024,6 @@ declare namespace entities {
         InviteListRequest,
         InviteListResponse,
         MahjongCancelMatchRequest,
-        MahjongCancelMatchResponse,
         MahjongCreateRoomResponse,
         MahjongGamesRequest,
         MahjongGamesResponse,
@@ -2837,9 +2836,6 @@ type IWebhooksUpdateRequest = operations['i___webhooks___update']['requestBody']
 // @public (undocumented)
 type MahjongCancelMatchRequest = operations['mahjong___cancel-match']['requestBody']['content']['application/json'];
 
-// @public (undocumented)
-type MahjongCancelMatchResponse = operations['mahjong___cancel-match']['responses']['200']['content']['application/json'];
-
 // @public (undocumented)
 type MahjongCreateRoomResponse = operations['mahjong___create-room']['responses']['200']['content']['application/json'];
 
diff --git a/packages/misskey-js/src/autogen/endpoint.ts b/packages/misskey-js/src/autogen/endpoint.ts
index 29c6c947e6..e94637e0e5 100644
--- a/packages/misskey-js/src/autogen/endpoint.ts
+++ b/packages/misskey-js/src/autogen/endpoint.ts
@@ -466,7 +466,6 @@ import type {
 	InviteListRequest,
 	InviteListResponse,
 	MahjongCancelMatchRequest,
-	MahjongCancelMatchResponse,
 	MahjongCreateRoomResponse,
 	MahjongGamesRequest,
 	MahjongGamesResponse,
@@ -950,7 +949,7 @@ export type Endpoints = {
 	'invite/delete': { req: InviteDeleteRequest; res: EmptyResponse };
 	'invite/limit': { req: EmptyRequest; res: InviteLimitResponse };
 	'invite/list': { req: InviteListRequest; res: InviteListResponse };
-	'mahjong/cancel-match': { req: MahjongCancelMatchRequest; res: MahjongCancelMatchResponse };
+	'mahjong/cancel-match': { req: MahjongCancelMatchRequest; res: EmptyResponse };
 	'mahjong/create-room': { req: EmptyRequest; res: MahjongCreateRoomResponse };
 	'mahjong/games': { req: MahjongGamesRequest; res: MahjongGamesResponse };
 	'mahjong/join-room': { req: MahjongJoinRoomRequest; res: MahjongJoinRoomResponse };
diff --git a/packages/misskey-js/src/autogen/entities.ts b/packages/misskey-js/src/autogen/entities.ts
index c41701413f..6e111ff67f 100644
--- a/packages/misskey-js/src/autogen/entities.ts
+++ b/packages/misskey-js/src/autogen/entities.ts
@@ -469,7 +469,6 @@ export type InviteLimitResponse = operations['invite___limit']['responses']['200
 export type InviteListRequest = operations['invite___list']['requestBody']['content']['application/json'];
 export type InviteListResponse = operations['invite___list']['responses']['200']['content']['application/json'];
 export type MahjongCancelMatchRequest = operations['mahjong___cancel-match']['requestBody']['content']['application/json'];
-export type MahjongCancelMatchResponse = operations['mahjong___cancel-match']['responses']['200']['content']['application/json'];
 export type MahjongCreateRoomResponse = operations['mahjong___create-room']['responses']['200']['content']['application/json'];
 export type MahjongGamesRequest = operations['mahjong___games']['requestBody']['content']['application/json'];
 export type MahjongGamesResponse = operations['mahjong___games']['responses']['200']['content']['application/json'];
diff --git a/packages/misskey-js/src/autogen/types.ts b/packages/misskey-js/src/autogen/types.ts
index dcab87e9f5..dc7b1744c2 100644
--- a/packages/misskey-js/src/autogen/types.ts
+++ b/packages/misskey-js/src/autogen/types.ts
@@ -23717,11 +23717,9 @@ export type operations = {
       };
     };
     responses: {
-      /** @description OK (with results) */
-      200: {
-        content: {
-          'application/json': unknown;
-        };
+      /** @description OK (without any results) */
+      204: {
+        content: never;
       };
       /** @description Client error */
       400: {