diff --git a/web/backend/api/config.go b/web/backend/api/config.go
index 091e3fbae..228f98c53 100644
--- a/web/backend/api/config.go
+++ b/web/backend/api/config.go
@@ -2,11 +2,13 @@ package api
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"net/http"
 
 	"github.com/sipeed/picoclaw/pkg/config"
+	"github.com/sipeed/picoclaw/pkg/credential"
 )
 
 // registerConfigRoutes binds configuration management endpoints to the ServeMux.
@@ -22,6 +24,10 @@ func (h *Handler) registerConfigRoutes(mux *http.ServeMux) {
 func (h *Handler) handleGetConfig(w http.ResponseWriter, r *http.Request) {
 	cfg, err := config.LoadConfig(h.configPath)
 	if err != nil {
+		if errors.Is(err, credential.ErrPassphraseRequired) || errors.Is(err, credential.ErrDecryptionFailed) {
+			http.Error(w, err.Error(), http.StatusLocked)
+			return
+		}
 		http.Error(w, fmt.Sprintf("Failed to load config: %v", err), http.StatusInternalServerError)
 		return
 	}
diff --git a/web/backend/api/gateway.go b/web/backend/api/gateway.go
index 10dd07610..5502c9197 100644
--- a/web/backend/api/gateway.go
+++ b/web/backend/api/gateway.go
@@ -109,11 +109,18 @@ func (h *Handler) gatewayStartReady() (bool, string, error) {
 		return false, "", fmt.Errorf("failed to load config: %w", err)
 	}
 
+	// If passphrase is required but not yet set, report that first so the
+	// frontend can prompt the user — even before checking the model name.
+	if h.passphraseStore != nil && !h.passphraseStore.IsSet() {
+		if configHasEncryptedCredentials(cfg) {
+			return false, "", credential.ErrPassphraseRequired
+		}
+	}
+
 	modelName := strings.TrimSpace(cfg.Agents.Defaults.GetModelName())
 	if modelName == "" {
 		return false, "no default model configured", nil
 	}
-
 	modelCfg := lookupModelConfig(cfg, modelName)
 	if modelCfg == nil {
 		return false, fmt.Sprintf("default model %q is invalid", modelName), nil
@@ -355,12 +362,14 @@ func (h *Handler) startGatewayLocked(initialStatus string) (int, error) {
 
 		// If we had an active passphrase attempt and the gateway crashed,
 		// mark passphrase as failed so the frontend can show an error.
+		// But do NOT clear the passphrase store: the gateway may have failed
+		// for reasons unrelated to the passphrase (e.g. missing default model,
+		// config error). Keeping the passphrase lets the user access
+		// /api/config and /api/models to fix the issue without re-entering it.
 		if exitErr != nil {
 			h.passphraseMu.Lock()
 			if h.passphraseLastState == passphraseStatePending {
 				h.passphraseLastState = passphraseStateFailed
-				// Clear the bad passphrase so user must re-enter
-				h.passphraseStore.Clear()
 			}
 			h.passphraseMu.Unlock()
 		} else {
@@ -833,3 +842,16 @@ func filterEnv(environ []string, key string) []string {
 	}
 	return result
 }
+
+// configHasEncryptedCredentials reports whether any model in cfg has an
+// api_key that uses the enc:// scheme, meaning a passphrase is required to
+// decrypt it before the gateway can start.
+func configHasEncryptedCredentials(cfg *config.Config) bool {
+	const encScheme = "enc://"
+	for _, m := range cfg.ModelList {
+		if strings.HasPrefix(m.APIKey, encScheme) {
+			return true
+		}
+	}
+	return false
+}
diff --git a/web/backend/api/models.go b/web/backend/api/models.go
index 7f3d29c77..7992ddea2 100644
--- a/web/backend/api/models.go
+++ b/web/backend/api/models.go
@@ -2,6 +2,7 @@ package api
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"net/http"
@@ -9,6 +10,7 @@ import (
 	"sync"
 
 	"github.com/sipeed/picoclaw/pkg/config"
+	"github.com/sipeed/picoclaw/pkg/credential"
 )
 
 // registerModelRoutes binds model list management endpoints to the ServeMux.
@@ -48,6 +50,10 @@ type modelResponse struct {
 func (h *Handler) handleListModels(w http.ResponseWriter, r *http.Request) {
 	cfg, err := config.LoadConfig(h.configPath)
 	if err != nil {
+		if errors.Is(err, credential.ErrPassphraseRequired) || errors.Is(err, credential.ErrDecryptionFailed) {
+			http.Error(w, err.Error(), http.StatusLocked)
+			return
+		}
 		http.Error(w, fmt.Sprintf("Failed to load config: %v", err), http.StatusInternalServerError)
 		return
 	}
diff --git a/web/backend/api/passphrase.go b/web/backend/api/passphrase.go
index 7602b5a77..c015a0bcd 100644
--- a/web/backend/api/passphrase.go
+++ b/web/backend/api/passphrase.go
@@ -52,10 +52,12 @@ func (h *Handler) handleSetPassphrase(w http.ResponseWriter, r *http.Request) {
 			log.Printf("Failed to start gateway after passphrase unlock: %v", err)
 			// startGatewayLocked failed before spawning the process, so the exit
 			// goroutine will never run. Transition pending → failed manually.
+			// Do NOT clear the passphrase: the failure may be a config issue
+			// (e.g. missing default model), not a wrong passphrase. Keeping it
+			// allows the user to access /api/config to fix the problem.
 			h.passphraseMu.Lock()
 			if h.passphraseLastState == passphraseStatePending {
 				h.passphraseLastState = passphraseStateFailed
-				h.passphraseStore.Clear()
 			}
 			h.passphraseMu.Unlock()
 			return
diff --git a/web/frontend/src/components/app-header.tsx b/web/frontend/src/components/app-header.tsx
index fe0c84e69..3e6b37504 100644
--- a/web/frontend/src/components/app-header.tsx
+++ b/web/frontend/src/components/app-header.tsx
@@ -6,7 +6,6 @@ import {
   IconMoon,
   IconPlayerPlay,
   IconPower,
-  IconRefresh,
   IconSun,
 } from "@tabler/icons-react"
 import { Link } from "@tanstack/react-router"
@@ -47,9 +46,7 @@ export function AppHeader() {
     state: gwState,
     loading: gwLoading,
     canStart,
-    restartRequired,
     start,
-    restart,
     stop,
   } = useGateway()
 
@@ -71,11 +68,6 @@ export function AppHeader() {
     }
   }
 
-  const handleGatewayRestart = () => {
-    if (gwLoading || isRestarting || !restartRequired || !canStart) return
-    void restart()
-  }
-
   const confirmStop = () => {
     setShowStopDialog(false)
     stop()
@@ -129,26 +121,6 @@ export function AppHeader() {
       </AlertDialog>
 
       <div className="text-muted-foreground flex items-center gap-1 text-sm font-medium md:gap-2">
-        {restartRequired && (
-          <Tooltip delayDuration={700}>
-            <TooltipTrigger asChild>
-              <Button
-                variant="secondary"
-                size="icon-sm"
-                className="bg-amber-500/15 text-amber-700 hover:bg-amber-500/25 hover:text-amber-800 dark:text-amber-300 dark:hover:bg-amber-500/25"
-                onClick={handleGatewayRestart}
-                disabled={gwLoading || isRestarting || !canStart}
-                aria-label={t("header.gateway.action.restart")}
-              >
-                <IconRefresh className="size-4" />
-              </Button>
-            </TooltipTrigger>
-            <TooltipContent>
-              {t("header.gateway.restartRequired")}
-            </TooltipContent>
-          </Tooltip>
-        )}
-
         {/* Gateway Start/Stop */}
         {isRunning ? (
           <Tooltip delayDuration={700}>
diff --git a/web/frontend/src/components/models/model-card.tsx b/web/frontend/src/components/models/model-card.tsx
index 316e05e4d..62ee8c173 100644
--- a/web/frontend/src/components/models/model-card.tsx
+++ b/web/frontend/src/components/models/model-card.tsx
@@ -28,7 +28,7 @@ export function ModelCard({
 }: ModelCardProps) {
   const { t } = useTranslation()
   const isOAuth = model.auth_method === "oauth"
-  const canSetDefault = model.configured && !model.is_default
+  const canSetDefault = !model.is_default
 
   return (
     <div
diff --git a/web/frontend/src/hooks/use-gateway.ts b/web/frontend/src/hooks/use-gateway.ts
index 53bef7894..6b69a560e 100644
--- a/web/frontend/src/hooks/use-gateway.ts
+++ b/web/frontend/src/hooks/use-gateway.ts
@@ -111,7 +111,6 @@ export function useGateway() {
       updateGatewayStore({
         status: "stopped",
         canStart: true,
-        restartRequired: false,
       })
     } catch (err) {
       console.error("Failed to stop gateway:", err)