diff --git a/adminfront/src/components/layout/AppLayout.tsx b/adminfront/src/components/layout/AppLayout.tsx
index 9f42e384..85eafa13 100644
--- a/adminfront/src/components/layout/AppLayout.tsx
+++ b/adminfront/src/components/layout/AppLayout.tsx
@@ -80,9 +80,23 @@ function AppLayout() {
     };
   }, []);
 
-  const { data: profile } = useQuery({
+  const {
+    data: profile,
+    isLoading: isProfileLoading,
+    error: profileError,
+  } = useQuery({
     queryKey: ["me"],
-    queryFn: fetchMe,
+    queryFn: async () => {
+      console.debug("[AppLayout] Fetching profile...");
+      try {
+        const data = await fetchMe();
+        console.debug("[AppLayout] Profile fetched successfully:", data.email);
+        return data;
+      } catch (err) {
+        console.error("[AppLayout] Failed to fetch profile:", err);
+        throw err;
+      }
+    },
     enabled:
       (auth.isAuthenticated && !auth.isLoading) ||
       import.meta.env.MODE === "development" ||
@@ -170,7 +184,15 @@ function AppLayout() {
     const isTest =
       (window as Window & typeof globalThis & { _IS_TEST_MODE?: boolean })
         ._IS_TEST_MODE === true;
+
+    console.debug("[AppLayout] Auth state check:", {
+      isLoading: auth.isLoading,
+      isAuthenticated: auth.isAuthenticated,
+      isTest,
+    });
+
     if (!auth.isLoading && !auth.isAuthenticated && !isTest) {
+      console.warn("[AppLayout] Not authenticated, redirecting to /login");
       navigate("/login");
     }
   }, [auth.isLoading, auth.isAuthenticated, navigate]);
diff --git a/adminfront/src/features/auth/AuthCallbackPage.tsx b/adminfront/src/features/auth/AuthCallbackPage.tsx
index ed1e0630..b7754b0a 100644
--- a/adminfront/src/features/auth/AuthCallbackPage.tsx
+++ b/adminfront/src/features/auth/AuthCallbackPage.tsx
@@ -8,6 +8,11 @@ function AuthCallbackPage() {
   const navigate = useNavigate();
 
   useEffect(() => {
+    console.debug("[AuthCallbackPage] State:", {
+      isAuthenticated: auth.isAuthenticated,
+      isLoading: auth.isLoading,
+      error: auth.error,
+    });
     if (auth.isAuthenticated) {
       // Save token to localStorage for existing API clients that might still use it
       const user = auth.user;
@@ -21,12 +26,16 @@ function AuthCallbackPage() {
         typeof auth.user.state.returnTo === "string"
           ? auth.user.state.returnTo
           : "/";
+      console.info(
+        "[AuthCallbackPage] Auth successful, navigating to",
+        returnTo,
+      );
       navigate(returnTo, { replace: true });
     } else if (auth.error) {
-      console.error("Auth Error:", auth.error);
+      console.error("[AuthCallbackPage] Auth Error:", auth.error);
       navigate("/login", { replace: true });
     }
-  }, [auth.isAuthenticated, auth.error, navigate, auth.user]);
+  }, [auth.isAuthenticated, auth.error, navigate, auth.user, auth.isLoading]);
 
   return (
     <div className="flex min-h-screen items-center justify-center bg-background">
diff --git a/adminfront/src/features/auth/LoginPage.tsx b/adminfront/src/features/auth/LoginPage.tsx
index bc6d780d..cdd807ab 100644
--- a/adminfront/src/features/auth/LoginPage.tsx
+++ b/adminfront/src/features/auth/LoginPage.tsx
@@ -20,10 +20,19 @@ function LoginPage() {
   const shouldAutoLogin = searchParams.get("auto") === "1";
 
   useEffect(() => {
+    console.debug("[LoginPage] Auth state check:", {
+      isAuthenticated: auth.isAuthenticated,
+      isLoading: auth.isLoading,
+      returnTo,
+    });
     if (auth.isAuthenticated) {
+      console.info(
+        "[LoginPage] User is authenticated, redirecting to",
+        returnTo,
+      );
       navigate(returnTo, { replace: true });
     }
-  }, [auth.isAuthenticated, navigate, returnTo]);
+  }, [auth.isAuthenticated, navigate, returnTo, auth.isLoading]);
 
   useEffect(() => {
     if (!shouldAutoLogin) {
@@ -64,6 +73,26 @@ function LoginPage() {
           </div>
         </div>
 
+        {auth.error && (
+          <div className="rounded-lg bg-destructive/15 p-4 text-sm text-destructive border border-destructive/20 animate-in fade-in slide-in-from-top-1">
+            <div className="font-bold flex items-center gap-2 mb-1">
+              <ShieldHalf size={16} />
+              인증 오류가 발생했습니다
+            </div>
+            <p className="opacity-90">{auth.error.message}</p>
+            <Button
+              variant="ghost"
+              className="p-0 h-auto text-destructive underline mt-2 hover:bg-transparent"
+              onClick={() => {
+                window.location.href =
+                  window.location.origin + window.location.pathname;
+              }}
+            >
+              다시 시도하기
+            </Button>
+          </div>
+        )}
+
         <Card className="border-primary/20 bg-card/50 backdrop-blur-xl shadow-2xl">
           <CardHeader className="space-y-1">
             <CardTitle className="text-2xl flex items-center gap-2">
diff --git a/adminfront/src/lib/apiClient.ts b/adminfront/src/lib/apiClient.ts
index aae7b63b..10782e7f 100644
--- a/adminfront/src/lib/apiClient.ts
+++ b/adminfront/src/lib/apiClient.ts
@@ -1,4 +1,5 @@
 import axios from "axios";
+import { userManager } from "./auth";
 
 const apiClient = axios.create({
   baseURL: (window as Window & typeof globalThis & { _IS_TEST_MODE?: boolean })
@@ -7,14 +8,17 @@ const apiClient = axios.create({
     : (import.meta.env.VITE_ADMIN_API_BASE ?? "/api"),
 });
 
-apiClient.interceptors.request.use((config) => {
-  // TODO: IdP 중립 Auth 레이어 연동 시 세션 토큰을 주입한다.
-  const sessionToken = window.localStorage.getItem("admin_session");
+apiClient.interceptors.request.use(async (config) => {
+  // IdP 중립 Auth 레이어 연동: oidc-client의 userManager에서 최신 토큰을 가져옵니다.
+  const user = await userManager.getUser();
+  const sessionToken =
+    user?.access_token || window.localStorage.getItem("admin_session");
+
   if (sessionToken) {
     config.headers.Authorization = `Bearer ${sessionToken}`;
   }
 
-  // TODO: 테넌트 선택 값을 보관하고 헤더로 전달한다.
+  // 테넌트 선택 값을 보관하고 헤더로 전달한다.
   const tenantId = window.localStorage.getItem("admin_tenant");
   if (tenantId) {
     config.headers["X-Tenant-ID"] = tenantId;
@@ -33,10 +37,29 @@ apiClient.interceptors.request.use((config) => {
 
 apiClient.interceptors.response.use(
   (response) => response,
-  (error) => {
+  async (error) => {
     if (error.response?.status === 401) {
+      console.warn(
+        "[apiClient] 401 Unauthorized detected. Clearing session state.",
+      );
+
+      // 로컬 스토리지의 세션 키 제거
       window.localStorage.removeItem("admin_session");
-      window.location.href = "/login";
+
+      // oidc-client의 유저 상태도 제거하여 isAuthenticated를 false로 만듭니다.
+      // 이를 통해 LoginPage에서의 무한 리다이렉션 루프를 방지합니다.
+      await userManager.removeUser();
+
+      const isAuthPath = window.location.pathname.startsWith("/auth/callback");
+      const isLoginPath = window.location.pathname === "/login";
+
+      if (!isAuthPath && !isLoginPath) {
+        console.info(
+          "[apiClient] Redirecting to /login from",
+          window.location.pathname,
+        );
+        window.location.href = "/login";
+      }
     }
     return Promise.reject(error);
   },
diff --git a/adminfront/src/lib/auth.ts b/adminfront/src/lib/auth.ts
index aab02a2b..6bf02cd7 100644
--- a/adminfront/src/lib/auth.ts
+++ b/adminfront/src/lib/auth.ts
@@ -2,13 +2,13 @@ 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 || "http://localhost:5000/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 || "adminfront",
   redirect_uri: `${window.location.origin}/auth/callback`,
   response_type: "code",
   scope: "openid offline_access profile email", // offline_access for refresh token
   post_logout_redirect_uri: window.location.origin,
+  popup_redirect_uri: `${window.location.origin}/auth/callback`,
   userStore: new WebStorageStateStore({ store: window.localStorage }),
   automaticSilentRenew: false,
 };
diff --git a/adminfront/src/lib/sessionSliding.ts b/adminfront/src/lib/sessionSliding.ts
index be152778..9caff6cd 100644
--- a/adminfront/src/lib/sessionSliding.ts
+++ b/adminfront/src/lib/sessionSliding.ts
@@ -29,18 +29,32 @@ export function shouldAttemptSlidingSessionRenew({
   }
 
   if (typeof expiresAtSec !== "number") {
+    console.debug(
+      "[sessionSliding] expiresAtSec is not a number, skipping renew",
+    );
     return false;
   }
 
   const remainingMs = expiresAtSec * 1000 - nowMs;
-  if (remainingMs <= 0 || remainingMs > thresholdMs) {
+  const remainingMin = Math.floor(remainingMs / 1000 / 60);
+
+  if (remainingMs <= 0) {
+    console.debug("[sessionSliding] Session already expired, skipping renew");
+    return false;
+  }
+
+  if (remainingMs > thresholdMs) {
     return false;
   }
 
   if (nowMs - lastAttemptAtMs < throttleMs) {
+    console.debug("[sessionSliding] Throttling renewal attempt");
     return false;
   }
 
+  console.info(
+    `[sessionSliding] Attempting sliding session renewal. Remaining: ${remainingMin}m`,
+  );
   return true;
 }
 
@@ -60,17 +74,33 @@ export function shouldAttemptUnlimitedSessionRenew({
   }
 
   if (typeof expiresAtSec !== "number") {
+    console.debug(
+      "[sessionSliding] expiresAtSec is not a number, skipping unlimited renew",
+    );
     return false;
   }
 
   const remainingMs = expiresAtSec * 1000 - nowMs;
-  if (remainingMs <= 0 || remainingMs > thresholdMs) {
+  const remainingMin = Math.floor(remainingMs / 1000 / 60);
+
+  if (remainingMs <= 0) {
+    console.debug(
+      "[sessionSliding] Session already expired, skipping unlimited renew",
+    );
+    return false;
+  }
+
+  if (remainingMs > thresholdMs) {
     return false;
   }
 
   if (nowMs - lastAttemptAtMs < throttleMs) {
+    console.debug("[sessionSliding] Throttling unlimited renewal attempt");
     return false;
   }
 
+  console.info(
+    `[sessionSliding] Attempting unlimited session renewal. Remaining: ${remainingMin}m`,
+  );
   return true;
 }
diff --git a/backend/cmd/server/main.go b/backend/cmd/server/main.go
index c2aedead..f82ff3af 100644
--- a/backend/cmd/server/main.go
+++ b/backend/cmd/server/main.go
@@ -687,7 +687,8 @@ func main() {
 
 	// Admin User Management
 	admin.Get("/users", requireAnyUser, userHandler.ListUsers)
-	admin.Get("/users/export", userHandler.ExportUsersCSV) // Removed requireAdmin to handle mock role in query param	admin.Post("/users", requireAdmin, userHandler.CreateUser)
+	admin.Get("/users/export", userHandler.ExportUsersCSV) // Removed requireAdmin to handle mock role in query param
+	admin.Post("/users", requireAdmin, userHandler.CreateUser)
 	admin.Post("/users/bulk", requireAdmin, userHandler.BulkCreateUsers)
 	admin.Put("/users/bulk", requireAdmin, userHandler.BulkUpdateUsers)
 	admin.Delete("/users/bulk", requireAdmin, userHandler.BulkDeleteUsers)
diff --git a/backend/internal/domain/idp_models.go b/backend/internal/domain/idp_models.go
index e22b9392..fd9b9168 100644
--- a/backend/internal/domain/idp_models.go
+++ b/backend/internal/domain/idp_models.go
@@ -53,6 +53,7 @@ type AuthInfo struct {
 	RefreshToken *Token
 	// Subject는 IDP 세션이 대표하는 주체(예: Kratos identity.id)를 나타냅니다.
 	Subject string
+	SetCookies   []*http.Cookie
 }
 
 // LinkLoginInit는 링크 로그인 초기화 결과입니다.
diff --git a/backend/internal/handler/auth_handler.go b/backend/internal/handler/auth_handler.go
index f7aed790..3c3ea26f 100644
--- a/backend/internal/handler/auth_handler.go
+++ b/backend/internal/handler/auth_handler.go
@@ -17,6 +17,7 @@ import (
 	"io"
 	"log/slog"
 	"math/rand"
+	"net"
 	"net/http"
 	"net/url"
 	"os"
@@ -1641,6 +1642,10 @@ func (h *AuthHandler) VerifyMagicLink(c *fiber.Ctx) error {
 	sessionToken := authInfo.SessionToken.JWT
 	c.Locals("login_id", loginID)
 	setSessionIDLocal(c, authInfo.SessionToken)
+
+	// Write Kratos session cookies to the response
+	h.writeAuthCookies(c, authInfo.SetCookies)
+
 	sessionID := extractSessionIDFromToken(authInfo.SessionToken)
 
 	slog.Info("[Verify] Success! Updating Redis session", "pendingRef", pendingRef)
@@ -1752,6 +1757,9 @@ func (h *AuthHandler) VerifyLoginCode(c *fiber.Ctx) error {
 	c.Locals("login_id", lookupLoginID)
 	setSessionIDLocal(c, authInfo.SessionToken)
 
+	// Write Kratos session cookies to the response
+	h.writeAuthCookies(c, authInfo.SetCookies)
+
 	h.RedisService.Delete(prefixLoginCode + lookupLoginID)
 	h.RedisService.Delete(prefixLoginCodeSmsTarget + lookupLoginID)
 
@@ -2414,6 +2422,10 @@ func (h *AuthHandler) completeApprovedLinkLogin(c *fiber.Ctx, pendingRef string)
 
 	c.Locals("login_id", loginID)
 	setSessionIDLocal(c, authInfo.SessionToken)
+
+	// Write Kratos session cookies to the response
+	h.writeAuthCookies(c, authInfo.SetCookies)
+
 	sessionID := extractSessionIDFromToken(authInfo.SessionToken)
 	if sessionID == "" && authInfo.SessionToken != nil && authInfo.SessionToken.JWT != "" {
 		if resolved, err := h.getKratosSessionID(authInfo.SessionToken.JWT); err == nil && resolved != "" {
@@ -2784,6 +2796,40 @@ func (h *AuthHandler) HeadlessLinkPoll(c *fiber.Ctx) error {
 	})
 }
 
+func (h *AuthHandler) writeAuthCookies(c *fiber.Ctx, cookies []*http.Cookie) {
+	if len(cookies) == 0 {
+		return
+	}
+
+	host := c.Hostname()
+	domain := ""
+
+	// IP address or localhost check
+	if ip := net.ParseIP(host); ip != nil || host == "localhost" {
+		domain = host
+	} else {
+		// Extract root domain (e.g., .hmac.kr from sso.hmac.kr)
+		parts := strings.Split(host, ".")
+		if len(parts) >= 2 {
+			domain = "." + strings.Join(parts[len(parts)-2:], ".")
+		}
+	}
+
+	for _, cookie := range cookies {
+		c.Cookie(&fiber.Cookie{
+			Name:     cookie.Name,
+			Value:    cookie.Value,
+			Path:     "/",
+			Domain:   domain,
+			MaxAge:   cookie.MaxAge,
+			Expires:  cookie.Expires,
+			Secure:   true,
+			HTTPOnly: true,
+			SameSite: "Lax",
+		})
+	}
+}
+
 func (h *AuthHandler) PasswordLogin(c *fiber.Ctx) error {
 	startTime := time.Now()
 	ale := logger.NewAuditLogEntry(c, "login")
@@ -2832,6 +2878,10 @@ func (h *AuthHandler) PasswordLogin(c *fiber.Ctx) error {
 	c.Locals("user_id", authInfo.Subject)
 	c.Locals("login_id", loginID)
 	setSessionIDLocal(c, authInfo.SessionToken)
+
+	// Write Kratos session cookies to the response
+	h.writeAuthCookies(c, authInfo.SetCookies)
+
 	if req.LoginChallenge == "" {
 		attachAuditClientDetails(c, domain.HydraClient{
 			ClientID:   "userfront",
@@ -2864,16 +2914,22 @@ func (h *AuthHandler) PasswordLogin(c *fiber.Ctx) error {
 			return fiber.NewError(fiber.StatusInternalServerError, "Failed to accept OIDC login request")
 		}
 		logOidcRedirectSummary("password_login", acceptResp.RedirectTo)
+
+		// IMPORTANT: Also return sessionJwt and token during OIDC flow to ensure portal session.
 		return c.JSON(fiber.Map{
 			"redirectTo": acceptResp.RedirectTo,
 			"status":     "ok",
 			"provider":   h.IdpProvider.Name(),
+			"sessionJwt": authInfo.SessionToken.JWT,
+			"token":      authInfo.SessionToken.JWT,
+			"subject":    authInfo.Subject,
 		})
 	}
 	// --- OIDC 로그인 흐름 처리 끝 ---
 
 	resp := fiber.Map{
 		"sessionJwt": authInfo.SessionToken.JWT,
+		"token":      authInfo.SessionToken.JWT,
 		"status":     "ok",
 		"provider":   h.IdpProvider.Name(),
 	}
diff --git a/backend/internal/handler/auth_handler_login_test.go b/backend/internal/handler/auth_handler_login_test.go
index 08d06e2b..64833990 100644
--- a/backend/internal/handler/auth_handler_login_test.go
+++ b/backend/internal/handler/auth_handler_login_test.go
@@ -633,8 +633,11 @@ func TestPasswordLogin_OIDC_Success(t *testing.T) {
 	if got["redirectTo"] != "http://rp/cb" {
 		t.Errorf("expected redirectTo http://rp/cb, got %v", got["redirectTo"])
 	}
-	if _, ok := got["sessionJwt"]; ok {
-		t.Errorf("expected OIDC response to omit sessionJwt, got %v", got["sessionJwt"])
+	if got["sessionJwt"] != "valid-jwt" {
+		t.Errorf("expected sessionJwt to be valid-jwt, got %v", got["sessionJwt"])
+	}
+	if got["token"] != "valid-jwt" {
+		t.Errorf("expected token to be valid-jwt, got %v", got["token"])
 	}
 }
 
diff --git a/backend/internal/service/ory_service.go b/backend/internal/service/ory_service.go
index 0eb08d68..1cb13ab6 100644
--- a/backend/internal/service/ory_service.go
+++ b/backend/internal/service/ory_service.go
@@ -247,7 +247,8 @@ func (o *OryProvider) SignIn(loginID, password string) (*domain.AuthInfo, error)
 			Expiration: result.SessionTokenExpiresAt,
 			SessionID:  result.Session.ID,
 		},
-		Subject: result.Session.Identity.ID,
+		Subject:    result.Session.Identity.ID,
+		SetCookies: resp.Cookies(),
 	}, nil
 }
 
@@ -693,7 +694,8 @@ func (o *OryProvider) VerifyLoginCode(loginID, flowID, code string) (*domain.Aut
 			Expiration: result.SessionTokenExpiresAt,
 			SessionID:  result.Session.ID,
 		},
-		Subject: result.Session.Identity.ID,
+		Subject:    result.Session.Identity.ID,
+		SetCookies: resp.Cookies(),
 	}, nil
 }
 
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 26069583..a0791fba 100644
--- a/devfront/src/features/auth/AuthGuard.tsx
+++ b/devfront/src/features/auth/AuthGuard.tsx
@@ -9,7 +9,21 @@ export default function AuthGuard() {
   }
 
   if (auth.error) {
-    return <div>Auth Error: {auth.error.message}</div>;
+    return (
+      <div className="flex min-h-screen flex-col items-center justify-center p-4 text-center">
+        <div className="mb-4 text-red-500">
+          <h2 className="text-xl font-bold">Authentication Error</h2>
+          <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"
+        >
+          Start Login Again
+        </button>
+      </div>
+    );
   }
 
   if (!auth.isAuthenticated) {
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 d0f0772e..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 || "http://localhost:5000/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",
diff --git a/userfront/lib/core/notifiers/auth_notifier.dart b/userfront/lib/core/notifiers/auth_notifier.dart
index 24282ca5..2591960a 100644
--- a/userfront/lib/core/notifiers/auth_notifier.dart
+++ b/userfront/lib/core/notifiers/auth_notifier.dart
@@ -1,8 +1,15 @@
 import 'package:flutter/foundation.dart';
+import '../services/auth_token_store.dart';
 
 class AuthNotifier extends ChangeNotifier {
   static final AuthNotifier instance = AuthNotifier();
 
+  Future<void> onLoginSuccess(String token, {String? provider}) async {
+    AuthTokenStore.setToken(token, provider: provider);
+    AuthTokenStore.clearPendingProvider();
+    notifyListeners();
+  }
+
   void notify() {
     notifyListeners();
   }
diff --git a/userfront/lib/core/services/auth_proxy_service.dart b/userfront/lib/core/services/auth_proxy_service.dart
index 252fdf32..59f3f0d5 100644
--- a/userfront/lib/core/services/auth_proxy_service.dart
+++ b/userfront/lib/core/services/auth_proxy_service.dart
@@ -92,6 +92,32 @@ class AuthProxyService {
     }
   }
 
+  static Future<Map<String, dynamic>> getMe({
+    String? token,
+    bool useCookie = true,
+  }) async {
+    final url = Uri.parse('$_baseUrl/api/v1/user/me');
+    final client = createHttpClient(withCredentials: useCookie);
+    try {
+      final headers = <String, String>{'Content-Type': 'application/json'};
+      if (!useCookie && token != null && token.isNotEmpty) {
+        headers['Authorization'] = 'Bearer $token';
+      }
+      final response = await client.get(url, headers: headers);
+
+      if (response.statusCode == 200) {
+        return jsonDecode(response.body);
+      }
+      throw _error(
+        'err.userfront.auth_proxy.profile_load',
+        '프로필을 불러오지 못했습니다: {{error}}',
+        detail: response.body,
+      );
+    } finally {
+      client.close();
+    }
+  }
+
   static Future<int> getSessionStatus({
     String? token,
     bool useCookie = false,
diff --git a/userfront/lib/core/services/auth_token_store.dart b/userfront/lib/core/services/auth_token_store.dart
index 253ff99d..c5133150 100644
--- a/userfront/lib/core/services/auth_token_store.dart
+++ b/userfront/lib/core/services/auth_token_store.dart
@@ -2,6 +2,11 @@ import 'auth_token_store_stub.dart'
     if (dart.library.js_interop) 'auth_token_store_web.dart';
 
 class AuthTokenStore {
+  static bool hasToken() {
+    final token = getToken();
+    return token != null && token.isNotEmpty;
+  }
+
   static String? getToken() => authTokenStore.getToken();
 
   static String? getProvider() => authTokenStore.getProvider();
diff --git a/userfront/lib/features/auth/presentation/login_screen.dart b/userfront/lib/features/auth/presentation/login_screen.dart
index bcb02973..b3824dc0 100644
--- a/userfront/lib/features/auth/presentation/login_screen.dart
+++ b/userfront/lib/features/auth/presentation/login_screen.dart
@@ -348,8 +348,19 @@ class _LoginScreenState extends ConsumerState<LoginScreen>
         loginChallenge,
         token: token,
       );
+
+      // IMPORTANT: If backend returned a token during OIDC flow, save it to fix login state.
+      final jwt = res['sessionJwt'] ?? res['token'] ?? token;
+      if (jwt != null && jwt.isNotEmpty) {
+        final provider =
+            res['provider'] as String? ?? AuthTokenStore.getProvider();
+        await AuthNotifier.instance.onLoginSuccess(jwt, provider: provider);
+      }
+
       final redirectTo = res['redirectTo'] as String?;
       if (redirectTo != null && redirectTo.isNotEmpty) {
+        // Give 50ms delay for localStorage to settle
+        await Future.delayed(const Duration(milliseconds: 50));
         return _redirectToOidcTarget(redirectTo, source: 'accept_oidc_login');
       }
     } catch (e) {
@@ -1294,10 +1305,22 @@ class _LoginScreenState extends ConsumerState<LoginScreen>
             loginChallenge,
             token: token,
           );
+
+          // IMPORTANT: If backend returned a token during OIDC flow, save it to fix login state.
+          final jwt = res['sessionJwt'] ?? res['token'] ?? token;
+          if (jwt != null && jwt.isNotEmpty) {
+            await AuthNotifier.instance.onLoginSuccess(
+              jwt,
+              provider: res['provider'] as String? ?? providerName,
+            );
+          }
+
           final nextRedirectTo = res['redirectTo'] as String?;
 
           if (nextRedirectTo != null && nextRedirectTo.isNotEmpty) {
             loginChallengeLoopGuard.clear(loginChallenge);
+            // Give 50ms delay for localStorage to settle
+            await Future.delayed(const Duration(milliseconds: 50));
             webWindow.redirectTo(nextRedirectTo); // Removed await
             return;
           } else {}
diff --git a/userfront/lib/main.dart b/userfront/lib/main.dart
index 774ecb66..4d0967d7 100644
--- a/userfront/lib/main.dart
+++ b/userfront/lib/main.dart
@@ -73,6 +73,45 @@ Future<void> _loadBundledFonts() async {
   }
 }
 
+Future<void> _silentSessionRecovery() async {
+  _log.info("[SessionRecovery] Starting silent session recovery check...");
+
+  // 1. Local token check
+  final hasLocalToken = AuthTokenStore.hasToken();
+  if (hasLocalToken) {
+    _log.info("[SessionRecovery] Local token found. Skipping recovery.");
+    return;
+  }
+
+  _log.info(
+    "[SessionRecovery] Local token missing. Checking for browser cookies...",
+  );
+
+  try {
+    // 2. Try fetching user info (backend will use cookies if present)
+    final userInfo = await AuthProxyService.getMe();
+    final subject = userInfo['id'] ?? userInfo['identity_id'] ?? '';
+
+    if (subject.isNotEmpty) {
+      _log.info(
+        "[SessionRecovery] Valid session found via cookies. Recovering login state...",
+      );
+      // For cookie-based auth, we don't necessarily have a JWT in local storage,
+      // but AuthNotifier needs to know we are logged in.
+      final jwt =
+          userInfo['sessionJwt'] ?? userInfo['token'] ?? 'cookie-session';
+      await AuthNotifier.instance.onLoginSuccess(jwt);
+      _log.info("[SessionRecovery] Recovery complete. Subject: $subject");
+    } else {
+      _log.warning("[SessionRecovery] Session found but subject is empty.");
+    }
+  } catch (e) {
+    _log.info(
+      "[SessionRecovery] No valid cookie session found or request failed: $e",
+    );
+  }
+}
+
 void main() async {
   WidgetsFlutterBinding.ensureInitialized();
   usePathUrlStrategy();
@@ -115,6 +154,9 @@ void main() async {
   // 폰트를 먼저 로딩해서 렌더링 깨짐(FOIT/FOUT) 최소화
   await _loadBundledFonts();
 
+  // 2. Silent Session Recovery (from cookies)
+  await _silentSessionRecovery();
+
   runApp(
     // URL(/en, /ko)이 있으면 우선 적용해서 첫 렌더부터 올바른 언어로 시작합니다.
     () {