diff --git a/packages/frontend/src/scripts/aiscript/api.ts b/packages/frontend/src/scripts/aiscript/api.ts
index 12f00bd32..1b47eaa42 100644
--- a/packages/frontend/src/scripts/aiscript/api.ts
+++ b/packages/frontend/src/scripts/aiscript/api.ts
@@ -27,7 +27,11 @@ export function createAiScriptEnv(opts) {
 			return confirm.canceled ? values.FALSE : values.TRUE;
 		}),
 		'Mk:api': values.FN_NATIVE(async ([ep, param, token]) => {
-			if (token) utils.assertString(token);
+			if (token) {
+				utils.assertString(token);
+				// バグがあればundefinedもあり得るため念のため
+				if (typeof token.value !== 'string') throw new Error('invalid token');
+			}
 			apiRequests++;
 			if (apiRequests > 16) return values.NULL;
 			const res = await os.api(ep.value, utils.valToJs(param), token ? token.value : (opts.token ?? null));