diff --git a/packages/backend/src/server/api/ApiServerService.ts b/packages/backend/src/server/api/ApiServerService.ts
index 709a044601..356e145681 100644
--- a/packages/backend/src/server/api/ApiServerService.ts
+++ b/packages/backend/src/server/api/ApiServerService.ts
@@ -118,6 +118,7 @@ export class ApiServerService {
 				'hcaptcha-response'?: string;
 				'g-recaptcha-response'?: string;
 				'turnstile-response'?: string;
+				'm-captcha-response'?: string;
 			}
 		}>('/signup', (request, reply) => this.signupApiService.signup(request, reply));
 
@@ -126,17 +127,18 @@ export class ApiServerService {
 				username: string;
 				password: string;
 				token?: string;
-				signature?: string;
-				authenticatorData?: string;
-				clientDataJSON?: string;
-				credentialId?: string;
-				challengeId?: string;
+				credential?: AuthenticationResponseJSON;
+				'hcaptcha-response'?: string;
+				'g-recaptcha-response'?: string;
+				'turnstile-response'?: string;
+				'm-captcha-response'?: string;
 			};
 		}>('/signin', (request, reply) => this.signinApiService.signin(request, reply));
 
 		fastify.post<{
 			Body: {
 				credential?: AuthenticationResponseJSON;
+				context?: string;
 			};
 		}>('/signin-with-passkey', (request, reply) => this.signinWithPasskeyApiService.signin(request, reply));
 
diff --git a/packages/frontend/src/components/MkSignin.vue b/packages/frontend/src/components/MkSignin.vue
index 8ebdac0220..abbff8e1f2 100644
--- a/packages/frontend/src/components/MkSignin.vue
+++ b/packages/frontend/src/components/MkSignin.vue
@@ -76,7 +76,6 @@ import { computed, defineAsyncComponent, ref } from 'vue';
 import { toUnicode } from 'punycode/';
 import * as Misskey from 'misskey-js';
 import { supported as webAuthnSupported, get as webAuthnRequest, parseRequestOptionsFromJSON } from '@github/webauthn-json/browser-ponyfill';
-import { SigninWithPasskeyResponse } from 'misskey-js/entities.js';
 import { query, extractDomain } from '@@/js/url.js';
 import { host as configHost } from '@@/js/config.js';
 import MkDivider from './MkDivider.vue';
@@ -188,7 +187,7 @@ function onPasskeyLogin(): void {
 	signing.value = true;
 	if (webAuthnSupported()) {
 		misskeyApi('signin-with-passkey', {})
-			.then((res: SigninWithPasskeyResponse) => {
+			.then(res => {
 				totpLogin.value = false;
 				signing.value = false;
 				queryingKey.value = true;
@@ -219,7 +218,7 @@ async function queryPasskey(): Promise<void> {
 				credential: credential.toJSON(),
 				context: passkey_context.value,
 			});
-		}).then((res: SigninWithPasskeyResponse) => {
+		}).then(res => {
 			emit('login', res.signinResponse);
 			return onLogin(res.signinResponse);
 		});
diff --git a/packages/misskey-js/etc/misskey-js.api.md b/packages/misskey-js/etc/misskey-js.api.md
index a5f12b41f4..5f4792eb74 100644
--- a/packages/misskey-js/etc/misskey-js.api.md
+++ b/packages/misskey-js/etc/misskey-js.api.md
@@ -4,7 +4,9 @@
 
 ```ts
 
+import type { AuthenticationResponseJSON } from '@simplewebauthn/types';
 import { EventEmitter } from 'eventemitter3';
+import type { PublicKeyCredentialRequestOptionsJSON } from '@simplewebauthn/types';
 
 // Warning: (ae-forgotten-export) The symbol "components" needs to be exported by the entry point index.d.ts
 //
@@ -1162,7 +1164,19 @@ export type Endpoints = Overwrite<Endpoints_2, {
     };
     'signin-with-passkey': {
         req: SigninWithPasskeyRequest;
-        res: SigninWithPasskeyResponse;
+        res: {
+            $switch: {
+                $cases: [
+                [
+                    {
+                    context: string;
+                },
+                SigninWithPasskeyResponse
+                ]
+                ];
+                $default: SigninWithPasskeyInitResponse;
+            };
+        };
     };
     'admin/roles/create': {
         req: Overwrite<AdminRolesCreateRequest, {
@@ -1196,6 +1210,7 @@ declare namespace entities {
         SignupPendingResponse,
         SigninRequest,
         SigninWithPasskeyRequest,
+        SigninWithPasskeyInitResponse,
         SigninWithPasskeyResponse,
         SigninResponse,
         PartialRolePolicyOverride,
@@ -3027,6 +3042,11 @@ type SigninRequest = {
     username: string;
     password: string;
     token?: string;
+    credential?: AuthenticationResponseJSON;
+    'hcaptcha-response'?: string | null;
+    'g-recaptcha-response'?: string | null;
+    'turnstile-response'?: string | null;
+    'm-captcha-response'?: string | null;
 };
 
 // @public (undocumented)
@@ -3035,17 +3055,21 @@ type SigninResponse = {
     i: string;
 };
 
+// @public (undocumented)
+type SigninWithPasskeyInitResponse = {
+    option: PublicKeyCredentialRequestOptionsJSON;
+    context: string;
+};
+
 // @public (undocumented)
 type SigninWithPasskeyRequest = {
-    credential?: object;
+    credential?: AuthenticationResponseJSON;
     context?: string;
 };
 
 // @public (undocumented)
 type SigninWithPasskeyResponse = {
-    option?: object;
-    context?: string;
-    signinResponse?: SigninResponse;
+    signinResponse: SigninResponse;
 };
 
 // @public (undocumented)
@@ -3069,6 +3093,7 @@ type SignupRequest = {
     'hcaptcha-response'?: string | null;
     'g-recaptcha-response'?: string | null;
     'turnstile-response'?: string | null;
+    'm-captcha-response'?: string | null;
 };
 
 // @public (undocumented)
@@ -3346,7 +3371,7 @@ type UsersUpdateMemoRequest = operations['users___update-memo']['requestBody']['
 
 // Warnings were encountered during analysis:
 //
-// src/entities.ts:49:2 - (ae-forgotten-export) The symbol "ModerationLogPayloads" needs to be exported by the entry point index.d.ts
+// src/entities.ts:50:2 - (ae-forgotten-export) The symbol "ModerationLogPayloads" needs to be exported by the entry point index.d.ts
 // src/streaming.types.ts:220:4 - (ae-forgotten-export) The symbol "ReversiUpdateKey" needs to be exported by the entry point index.d.ts
 // src/streaming.types.ts:230:4 - (ae-forgotten-export) The symbol "ReversiUpdateSettings" needs to be exported by the entry point index.d.ts
 
diff --git a/packages/misskey-js/package.json b/packages/misskey-js/package.json
index b41f0057a3..badc4f64ff 100644
--- a/packages/misskey-js/package.json
+++ b/packages/misskey-js/package.json
@@ -57,6 +57,7 @@
 		"built"
 	],
 	"dependencies": {
+		"@simplewebauthn/types": "10.0.0",
 		"eventemitter3": "5.0.1",
 		"reconnecting-websocket": "4.4.0"
 	}
diff --git a/packages/misskey-js/src/api.types.ts b/packages/misskey-js/src/api.types.ts
index 4c3f2e1578..cef5ab8861 100644
--- a/packages/misskey-js/src/api.types.ts
+++ b/packages/misskey-js/src/api.types.ts
@@ -5,6 +5,7 @@ import {
 	PartialRolePolicyOverride,
 	SigninRequest,
 	SigninResponse,
+	SigninWithPasskeyInitResponse,
 	SigninWithPasskeyRequest,
 	SigninWithPasskeyResponse,
 	SignupPendingRequest,
@@ -86,8 +87,20 @@ export type Endpoints = Overwrite<
 		},
 		'signin-with-passkey': {
 			req: SigninWithPasskeyRequest;
-			res: SigninWithPasskeyResponse;
-		}
+			res: {
+				$switch: {
+					$cases: [
+						[
+							{
+								context: string;
+							},
+							SigninWithPasskeyResponse,
+						],
+					];
+					$default: SigninWithPasskeyInitResponse;
+				},
+			},
+		},
 		'admin/roles/create': {
 			req: Overwrite<AdminRolesCreateRequest, { policies: PartialRolePolicyOverride }>;
 			res: AdminRolesCreateResponse;
diff --git a/packages/misskey-js/src/entities.ts b/packages/misskey-js/src/entities.ts
index 64ed90cbb1..36b7f5bca3 100644
--- a/packages/misskey-js/src/entities.ts
+++ b/packages/misskey-js/src/entities.ts
@@ -10,6 +10,7 @@ import {
 	User,
 	UserDetailedNotMe,
 } from './autogen/models.js';
+import type { AuthenticationResponseJSON, PublicKeyCredentialRequestOptionsJSON } from '@simplewebauthn/types';
 
 export * from './autogen/entities.js';
 export * from './autogen/models.js';
@@ -250,6 +251,7 @@ export type SignupRequest = {
 	'hcaptcha-response'?: string | null;
 	'g-recaptcha-response'?: string | null;
 	'turnstile-response'?: string | null;
+	'm-captcha-response'?: string | null;
 }
 
 export type SignupResponse = MeDetailed & {
@@ -269,17 +271,25 @@ export type SigninRequest = {
 	username: string;
 	password: string;
 	token?: string;
+	credential?: AuthenticationResponseJSON;
+	'hcaptcha-response'?: string | null;
+	'g-recaptcha-response'?: string | null;
+	'turnstile-response'?: string | null;
+	'm-captcha-response'?: string | null;
 };
 
 export type SigninWithPasskeyRequest = {
-	credential?: object;
+	credential?: AuthenticationResponseJSON;
 	context?: string;
 };
 
+export type SigninWithPasskeyInitResponse = {
+	option: PublicKeyCredentialRequestOptionsJSON;
+	context: string;
+};
+
 export type SigninWithPasskeyResponse = {
-	option?: object;
-	context?: string;
-	signinResponse?: SigninResponse;
+	signinResponse: SigninResponse;
 };
 
 export type SigninResponse = {
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 5d7febbcc9..53d5dbbde0 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -1289,6 +1289,9 @@ importers:
 
   packages/misskey-js:
     dependencies:
+      '@simplewebauthn/types':
+        specifier: 10.0.0
+        version: 10.0.0
       eventemitter3:
         specifier: 5.0.1
         version: 5.0.1