diff --git a/devfront/playwright.config.ts b/devfront/playwright.config.ts
index 1910fa4c..c4ad1449 100644
--- a/devfront/playwright.config.ts
+++ b/devfront/playwright.config.ts
@@ -63,8 +63,8 @@ export default defineConfig({
     ? undefined
     : {
         command: process.env.CI
-          ? "npm run build && npm run preview -- --port 5174"
-          : "npm run dev -- --port 5174",
+          ? "VITE_OIDC_AUTHORITY=http://localhost:5000/oidc npm run build && npm run preview -- --port 5174"
+          : "VITE_OIDC_AUTHORITY=http://localhost:5000/oidc npm run dev -- --port 5174",
         url: baseURL,
         reuseExistingServer: !process.env.CI,
       },
diff --git a/devfront/src/features/auth/AuthGuard.tsx b/devfront/src/features/auth/AuthGuard.tsx
index e204b150..a0791fba 100644
--- a/devfront/src/features/auth/AuthGuard.tsx
+++ b/devfront/src/features/auth/AuthGuard.tsx
@@ -16,6 +16,7 @@ export default function AuthGuard() {
           <p>{auth.error.message}</p>
         </div>
         <button
+          type="button"
           onClick={() => void auth.signinRedirect()}
           className="rounded bg-blue-500 px-4 py-2 text-white hover:bg-blue-600"
         >
diff --git a/devfront/src/features/clients/ClientGeneralPage.tsx b/devfront/src/features/clients/ClientGeneralPage.tsx
index a19ee5ed..91590fba 100644
--- a/devfront/src/features/clients/ClientGeneralPage.tsx
+++ b/devfront/src/features/clients/ClientGeneralPage.tsx
@@ -524,16 +524,17 @@ function ClientGeneralPage() {
       if (result?.client?.id) {
         navigate(`/clients/${result.client.id}/settings`);
       }
-      alert(t("msg.dev.clients.general.saved", "설정이 저장되었습니다."));
+      toast(t("msg.dev.clients.general.saved", "설정이 저장되었습니다."));
     },
     onError: (err) => {
       const axiosError = err as AxiosError<{ error?: string }>;
       if (axiosError.response?.status === 403) {
-        alert(
+        toast(
           t(
             "msg.dev.clients.general.save_forbidden",
             "이 RP 설정을 수정할 권한이 없습니다.\n관리자에게 RP 일반 설정 또는 RP 관리자 관계 부여를 요청해 주세요.",
           ),
+          "error",
         );
         return;
       }
@@ -542,7 +543,7 @@ function ClientGeneralPage() {
         axiosError.response?.data?.error ??
         (err as Error)?.message ??
         t("msg.common.unknown_error", "unknown error");
-      alert(
+      toast(
         t(
           "msg.dev.clients.general.save_error",
           "저장에 실패했습니다: {{error}}",
@@ -550,6 +551,7 @@ function ClientGeneralPage() {
             error: errorMessage,
           },
         ),
+        "error",
       );
     },
   });
@@ -558,17 +560,18 @@ function ClientGeneralPage() {
     mutationFn: (id: string) => deleteClient(id),
     onSuccess: () => {
       queryClient.invalidateQueries({ queryKey: ["clients"] });
-      alert(t("msg.dev.clients.deleted", "앱이 삭제되었습니다."));
+      toast(t("msg.dev.clients.deleted", "앱이 삭제되었습니다."));
       navigate("/clients");
     },
     onError: (err) => {
       const errorMessage =
         (err as AxiosError<{ error?: string }>).response?.data?.error ??
         (err as Error)?.message;
-      alert(
+      toast(
         t("msg.dev.clients.delete_error", "삭제 실패: {{error}}", {
           error: errorMessage,
         }),
+        "error",
       );
     },
   });
diff --git a/devfront/src/features/clients/ClientRelationsPage.tsx b/devfront/src/features/clients/ClientRelationsPage.tsx
index 23be2dfb..e93e9260 100644
--- a/devfront/src/features/clients/ClientRelationsPage.tsx
+++ b/devfront/src/features/clients/ClientRelationsPage.tsx
@@ -2,6 +2,7 @@ import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
 import type { AxiosError } from "axios";
 import { ArrowLeft, Link2, Plus, Trash2 } from "lucide-react";
 import { useDeferredValue, useMemo, useState } from "react";
+import { useAuth } from "react-oidc-context";
 import { Link, useParams } from "react-router-dom";
 import { Badge } from "../../components/ui/badge";
 import { Button } from "../../components/ui/button";
@@ -33,7 +34,6 @@ import {
 } from "../../lib/devApi";
 import { t } from "../../lib/i18n";
 import { resolveProfileRole } from "../../lib/role";
-import { useAuth } from "react-oidc-context";
 import { ClientDetailTabs } from "./ClientDetailTabs";
 
 const relationOptions = [
diff --git a/devfront/src/lib/auth.ts b/devfront/src/lib/auth.ts
index 210b507d..f0e7ea3a 100644
--- a/devfront/src/lib/auth.ts
+++ b/devfront/src/lib/auth.ts
@@ -2,8 +2,7 @@ import { UserManager, WebStorageStateStore } from "oidc-client-ts";
 import type { AuthProviderProps } from "react-oidc-context";
 
 export const oidcConfig: AuthProviderProps = {
-  authority:
-    import.meta.env.VITE_OIDC_AUTHORITY || "https://sso.hmac.kr/oidc", // Gateway Proxy URL
+  authority: import.meta.env.VITE_OIDC_AUTHORITY || "https://sso.hmac.kr/oidc", // Gateway Proxy URL
   client_id: import.meta.env.VITE_OIDC_CLIENT_ID || "devfront",
   redirect_uri: `${window.location.origin}/auth/callback`,
   response_type: "code",