diff --git a/packages/frontend/src/components/MkSignin.vue b/packages/frontend/src/components/MkSignin.vue
index 93a29b0b54..b2f0f4ddcf 100644
--- a/packages/frontend/src/components/MkSignin.vue
+++ b/packages/frontend/src/components/MkSignin.vue
@@ -120,6 +120,7 @@ function onPasskeyLogin(): void {
 			.then((res) => {
 				passkeyContext.value = res.context ?? '';
 				credentialRequest.value = parseRequestOptionsFromJSON({
+					// @ts-expect-error TODO: misskey-js由来の型（@simplewebauthn/types）とフロントエンド由来の型（@github/webauthn-json）が合わない
 					publicKey: res.option,
 				});
 
@@ -134,7 +135,7 @@ function onPasskeyDone(credential: AuthenticationPublicKeyCredential): void {
 	waiting.value = true;
 
 	if (doingPasskeyFromInputPage.value) {
-		misskeyApi('signin-with-passkey', {
+		misskeyApi<Misskey.entities.SigninWithPasskeyResponse>('signin-with-passkey', {
 			credential: credential.toJSON(),
 			context: passkeyContext.value,
 		}).then((res) => {
@@ -149,6 +150,7 @@ function onPasskeyDone(credential: AuthenticationPublicKeyCredential): void {
 		tryLogin({
 			username: userInfo.value.username,
 			password: password.value,
+			// @ts-expect-error TODO: misskey-js由来の型（@simplewebauthn/types）とフロントエンド由来の型（@github/webauthn-json）が合わない
 			credential: credential.toJSON(),
 		});
 	}
@@ -253,6 +255,7 @@ async function tryLogin(req: Partial<Misskey.entities.SigninFlowRequest>): Promi
 				case 'passkey': {
 					if (webAuthnSupported()) {
 						credentialRequest.value = parseRequestOptionsFromJSON({
+							// @ts-expect-error TODO: misskey-js由来の型（@simplewebauthn/types）とフロントエンド由来の型（@github/webauthn-json）が合わない
 							publicKey: res.authRequest,
 						});
 						page.value = 'passkey';
diff --git a/packages/misskey-js/etc/misskey-js.api.md b/packages/misskey-js/etc/misskey-js.api.md
index bb490c178b..fe19c00a80 100644
--- a/packages/misskey-js/etc/misskey-js.api.md
+++ b/packages/misskey-js/etc/misskey-js.api.md
@@ -3512,6 +3512,7 @@ type SigninFlowRequest = {
     'g-recaptcha-response'?: string | null;
     'turnstile-response'?: string | null;
     'm-captcha-response'?: string | null;
+    'testcaptcha-response'?: string | null;
 };
 
 // @public (undocumented)
diff --git a/packages/misskey-js/src/entities.ts b/packages/misskey-js/src/entities.ts
index b64dd451a2..a32bc56a57 100644
--- a/packages/misskey-js/src/entities.ts
+++ b/packages/misskey-js/src/entities.ts
@@ -294,6 +294,7 @@ export type SigninFlowRequest = {
 	'g-recaptcha-response'?: string | null;
 	'turnstile-response'?: string | null;
 	'm-captcha-response'?: string | null;
+	'testcaptcha-response'?: string | null;
 };
 
 export type SigninFlowResponse = {