diff --git a/backend/internal/handler/admin/gemini_oauth_handler.go b/backend/internal/handler/admin/gemini_oauth_handler.go
index 50caaa26..8c398a1e 100644
--- a/backend/internal/handler/admin/gemini_oauth_handler.go
+++ b/backend/internal/handler/admin/gemini_oauth_handler.go
@@ -61,7 +61,11 @@ func (h *GeminiOAuthHandler) GenerateAuthURL(c *gin.Context) {
 	if err != nil {
 		msg := err.Error()
 		// Treat missing/invalid OAuth client configuration as a user/config error.
-		if strings.Contains(msg, "OAuth client not configured") || strings.Contains(msg, "requires your own OAuth Client") {
+		if strings.Contains(msg, "OAuth client not configured") ||
+			strings.Contains(msg, "requires your own OAuth Client") ||
+			strings.Contains(msg, "requires a custom OAuth Client") ||
+			strings.Contains(msg, "GEMINI_CLI_OAUTH_CLIENT_SECRET_MISSING") ||
+			strings.Contains(msg, "built-in Gemini CLI OAuth client_secret is not configured") {
 			response.BadRequest(c, "Failed to generate auth URL: "+msg)
 			return
 		}
diff --git a/backend/internal/pkg/geminicli/constants.go b/backend/internal/pkg/geminicli/constants.go
index f85e3b97..97234ffd 100644
--- a/backend/internal/pkg/geminicli/constants.go
+++ b/backend/internal/pkg/geminicli/constants.go
@@ -38,10 +38,8 @@ const (
 	// GeminiCLIOAuthClientID/Secret are the public OAuth client credentials used by Google Gemini CLI.
 	// They enable the "login without creating your own OAuth client" experience, but Google may
 	// restrict which scopes are allowed for this client.
-	GeminiCLIOAuthClientID = "681255809395-oo8ft2oprdrnp9e3aqf6av3hmdib135j.apps.googleusercontent.com"
-	// GeminiCLIOAuthClientSecret is intentionally not embedded in this repository.
-	// If you rely on the built-in Gemini CLI OAuth client, you MUST provide its client_secret via config/env.
-	GeminiCLIOAuthClientSecret = ""
+	GeminiCLIOAuthClientID     = "681255809395-oo8ft2oprdrnp9e3aqf6av3hmdib135j.apps.googleusercontent.com"
+	GeminiCLIOAuthClientSecret = "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"
 
 	// GeminiCLIOAuthClientSecretEnv is the environment variable name for the built-in client secret.
 	GeminiCLIOAuthClientSecretEnv = "GEMINI_CLI_OAUTH_CLIENT_SECRET"
diff --git a/backend/internal/pkg/geminicli/oauth_test.go b/backend/internal/pkg/geminicli/oauth_test.go
index 14bc3c6b..2a430f9e 100644
--- a/backend/internal/pkg/geminicli/oauth_test.go
+++ b/backend/internal/pkg/geminicli/oauth_test.go
@@ -408,11 +408,10 @@ func TestBuildAuthorizationURL_WithProjectID(t *testing.T) {
 	}
 }
 
-func TestBuildAuthorizationURL_OAuthConfigError(t *testing.T) {
-	// 不设置环境变量，也不提供 client 凭据，EffectiveOAuthConfig 应该报错
+func TestBuildAuthorizationURL_UsesBuiltinSecretFallback(t *testing.T) {
 	t.Setenv(GeminiCLIOAuthClientSecretEnv, "")
 
-	_, err := BuildAuthorizationURL(
+	authURL, err := BuildAuthorizationURL(
 		OAuthConfig{},
 		"test-state",
 		"test-challenge",
@@ -420,8 +419,11 @@ func TestBuildAuthorizationURL_OAuthConfigError(t *testing.T) {
 		"",
 		"code_assist",
 	)
-	if err == nil {
-		t.Error("当 EffectiveOAuthConfig 失败时，BuildAuthorizationURL 应该返回错误")
+	if err != nil {
+		t.Fatalf("BuildAuthorizationURL() 不应报错: %v", err)
+	}
+	if !strings.Contains(authURL, "client_id="+GeminiCLIOAuthClientID) {
+		t.Errorf("应使用内置 Gemini CLI client_id，实际 URL: %s", authURL)
 	}
 }
 
@@ -685,15 +687,17 @@ func TestEffectiveOAuthConfig_WhitespaceTriming(t *testing.T) {
 }
 
 func TestEffectiveOAuthConfig_NoEnvSecret(t *testing.T) {
-	// 不设置环境变量且不提供凭据，应该报错
 	t.Setenv(GeminiCLIOAuthClientSecretEnv, "")
 
-	_, err := EffectiveOAuthConfig(OAuthConfig{}, "code_assist")
-	if err == nil {
-		t.Error("没有内置 secret 且未提供凭据时应该报错")
+	cfg, err := EffectiveOAuthConfig(OAuthConfig{}, "code_assist")
+	if err != nil {
+		t.Fatalf("不设置环境变量时应回退到内置 secret，实际报错: %v", err)
 	}
-	if !strings.Contains(err.Error(), GeminiCLIOAuthClientSecretEnv) {
-		t.Errorf("错误消息应提及环境变量 %s，实际: %v", GeminiCLIOAuthClientSecretEnv, err)
+	if strings.TrimSpace(cfg.ClientSecret) == "" {
+		t.Error("ClientSecret 不应为空")
+	}
+	if cfg.ClientID != GeminiCLIOAuthClientID {
+		t.Errorf("ClientID 应回退为内置客户端 ID，实际: %q", cfg.ClientID)
 	}
 }
 
diff --git a/backend/internal/service/account.go b/backend/internal/service/account.go
index 51ab84dd..6ac185dc 100644
--- a/backend/internal/service/account.go
+++ b/backend/internal/service/account.go
@@ -372,6 +372,9 @@ func (a *Account) GetModelMapping() map[string]string {
 			}
 		}
 		if len(result) > 0 {
+			if a.Platform == domain.PlatformAntigravity {
+				ensureAntigravityDefaultPassthrough(result, "gemini-3-flash")
+			}
 			return result
 		}
 	}
@@ -382,6 +385,21 @@ func (a *Account) GetModelMapping() map[string]string {
 	return nil
 }
 
+func ensureAntigravityDefaultPassthrough(mapping map[string]string, model string) {
+	if mapping == nil || model == "" {
+		return
+	}
+	if _, exists := mapping[model]; exists {
+		return
+	}
+	for pattern := range mapping {
+		if matchWildcard(pattern, model) {
+			return
+		}
+	}
+	mapping[model] = model
+}
+
 // IsModelSupported 检查模型是否在 model_mapping 中（支持通配符）
 // 如果未配置 mapping，返回 true（允许所有模型）
 func (a *Account) IsModelSupported(requestedModel string) bool {
diff --git a/backend/internal/service/account_usage_service.go b/backend/internal/service/account_usage_service.go
index 7698223e..a363a790 100644
--- a/backend/internal/service/account_usage_service.go
+++ b/backend/internal/service/account_usage_service.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"log"
+	"strings"
 	"sync"
 	"time"
 
@@ -217,12 +218,20 @@ func (s *AccountUsageService) GetUsage(ctx context.Context, accountID int64) (*U
 	}
 
 	if account.Platform == PlatformGemini {
-		return s.getGeminiUsage(ctx, account)
+		usage, err := s.getGeminiUsage(ctx, account)
+		if err == nil {
+			s.tryClearRecoverableAccountError(ctx, account)
+		}
+		return usage, err
 	}
 
 	// Antigravity 平台：使用 AntigravityQuotaFetcher 获取额度
 	if account.Platform == PlatformAntigravity {
-		return s.getAntigravityUsage(ctx, account)
+		usage, err := s.getAntigravityUsage(ctx, account)
+		if err == nil {
+			s.tryClearRecoverableAccountError(ctx, account)
+		}
+		return usage, err
 	}
 
 	// 只有oauth类型账号可以通过API获取usage（有profile scope）
@@ -256,6 +265,7 @@ func (s *AccountUsageService) GetUsage(ctx context.Context, accountID int64) (*U
 		// 4. 添加窗口统计（有独立缓存，1 分钟）
 		s.addWindowStats(ctx, account, usage)
 
+		s.tryClearRecoverableAccountError(ctx, account)
 		return usage, nil
 	}
 
@@ -486,6 +496,32 @@ func parseTime(s string) (time.Time, error) {
 	return time.Time{}, fmt.Errorf("unable to parse time: %s", s)
 }
 
+func (s *AccountUsageService) tryClearRecoverableAccountError(ctx context.Context, account *Account) {
+	if account == nil || account.Status != StatusError {
+		return
+	}
+
+	msg := strings.ToLower(strings.TrimSpace(account.ErrorMessage))
+	if msg == "" {
+		return
+	}
+
+	if !strings.Contains(msg, "token refresh failed") &&
+		!strings.Contains(msg, "invalid_client") &&
+		!strings.Contains(msg, "missing_project_id") &&
+		!strings.Contains(msg, "unauthenticated") {
+		return
+	}
+
+	if err := s.accountRepo.ClearError(ctx, account.ID); err != nil {
+		log.Printf("[usage] failed to clear recoverable account error for account %d: %v", account.ID, err)
+		return
+	}
+
+	account.Status = StatusActive
+	account.ErrorMessage = ""
+}
+
 // buildUsageInfo 构建UsageInfo
 func (s *AccountUsageService) buildUsageInfo(resp *ClaudeUsageResponse, updatedAt *time.Time) *UsageInfo {
 	info := &UsageInfo{
diff --git a/backend/internal/service/account_wildcard_test.go b/backend/internal/service/account_wildcard_test.go
index 90e5b573..c78ce554 100644
--- a/backend/internal/service/account_wildcard_test.go
+++ b/backend/internal/service/account_wildcard_test.go
@@ -267,3 +267,38 @@ func TestAccountGetMappedModel(t *testing.T) {
 		})
 	}
 }
+
+func TestAccountGetModelMapping_AntigravityEnsuresGemini3FlashPassthrough(t *testing.T) {
+	account := &Account{
+		Platform: PlatformAntigravity,
+		Credentials: map[string]any{
+			"model_mapping": map[string]any{
+				"gemini-3-pro-high": "gemini-3.1-pro-high",
+			},
+		},
+	}
+
+	mapping := account.GetModelMapping()
+	if mapping["gemini-3-flash"] != "gemini-3-flash" {
+		t.Fatalf("expected gemini-3-flash passthrough to be auto-filled, got: %q", mapping["gemini-3-flash"])
+	}
+}
+
+func TestAccountGetModelMapping_AntigravityRespectsWildcardOverride(t *testing.T) {
+	account := &Account{
+		Platform: PlatformAntigravity,
+		Credentials: map[string]any{
+			"model_mapping": map[string]any{
+				"gemini-3*": "gemini-3.1-pro-high",
+			},
+		},
+	}
+
+	mapping := account.GetModelMapping()
+	if _, exists := mapping["gemini-3-flash"]; exists {
+		t.Fatalf("did not expect explicit gemini-3-flash passthrough when wildcard already exists")
+	}
+	if mapped := account.GetMappedModel("gemini-3-flash"); mapped != "gemini-3.1-pro-high" {
+		t.Fatalf("expected wildcard mapping to stay effective, got: %q", mapped)
+	}
+}
diff --git a/frontend/src/components/account/BulkEditAccountModal.vue b/frontend/src/components/account/BulkEditAccountModal.vue
index 0997f6ee..1c4395ec 100644
--- a/frontend/src/components/account/BulkEditAccountModal.vue
+++ b/frontend/src/components/account/BulkEditAccountModal.vue
@@ -768,6 +768,31 @@ const presetMappings = [
     color:
       'bg-purple-100 text-purple-700 hover:bg-purple-200 dark:bg-purple-900/30 dark:text-purple-400'
   },
+  {
+    label: 'Sonnet4→4.6',
+    from: 'claude-sonnet-4-20250514',
+    to: 'claude-sonnet-4-6',
+    color: 'bg-sky-100 text-sky-700 hover:bg-sky-200 dark:bg-sky-900/30 dark:text-sky-400'
+  },
+  {
+    label: 'Sonnet4.5→4.6',
+    from: 'claude-sonnet-4-5-20250929',
+    to: 'claude-sonnet-4-6',
+    color: 'bg-cyan-100 text-cyan-700 hover:bg-cyan-200 dark:bg-cyan-900/30 dark:text-cyan-400'
+  },
+  {
+    label: 'Sonnet3.5→4.6',
+    from: 'claude-3-5-sonnet-20241022',
+    to: 'claude-sonnet-4-6',
+    color: 'bg-teal-100 text-teal-700 hover:bg-teal-200 dark:bg-teal-900/30 dark:text-teal-400'
+  },
+  {
+    label: 'Opus4.5→4.6',
+    from: 'claude-opus-4-5-20251101',
+    to: 'claude-opus-4-6-thinking',
+    color:
+      'bg-violet-100 text-violet-700 hover:bg-violet-200 dark:bg-violet-900/30 dark:text-violet-400'
+  },
   {
     label: 'Opus->Sonnet',
     from: 'claude-opus-4-5-20251101',
@@ -793,22 +818,34 @@ const presetMappings = [
     color: 'bg-pink-100 text-pink-700 hover:bg-pink-200 dark:bg-pink-900/30 dark:text-pink-400'
   },
   {
-    label: 'Gemini Flash 2.0',
-    from: 'gemini-2.0-flash',
-    to: 'gemini-2.0-flash',
-    color: 'bg-cyan-100 text-cyan-700 hover:bg-cyan-200 dark:bg-cyan-900/30 dark:text-cyan-400'
+    label: '3-Pro-Preview→3.1-Pro-High',
+    from: 'gemini-3-pro-preview',
+    to: 'gemini-3.1-pro-high',
+    color: 'bg-amber-100 text-amber-700 hover:bg-amber-200 dark:bg-amber-900/30 dark:text-amber-400'
   },
   {
-    label: 'Gemini 2.5 Flash',
-    from: 'gemini-2.5-flash',
-    to: 'gemini-2.5-flash',
-    color: 'bg-teal-100 text-teal-700 hover:bg-teal-200 dark:bg-teal-900/30 dark:text-teal-400'
+    label: '3-Pro-High→3.1-Pro-High',
+    from: 'gemini-3-pro-high',
+    to: 'gemini-3.1-pro-high',
+    color: 'bg-orange-100 text-orange-700 hover:bg-orange-200 dark:bg-orange-900/30 dark:text-orange-400'
   },
   {
-    label: 'Gemini 2.5 Pro',
-    from: 'gemini-2.5-pro',
-    to: 'gemini-2.5-pro',
-    color: 'bg-sky-100 text-sky-700 hover:bg-sky-200 dark:bg-sky-900/30 dark:text-sky-400'
+    label: '3-Pro-Low→3.1-Pro-Low',
+    from: 'gemini-3-pro-low',
+    to: 'gemini-3.1-pro-low',
+    color: 'bg-yellow-100 text-yellow-700 hover:bg-yellow-200 dark:bg-yellow-900/30 dark:text-yellow-400'
+  },
+  {
+    label: '3-Flash透传',
+    from: 'gemini-3-flash',
+    to: 'gemini-3-flash',
+    color: 'bg-lime-100 text-lime-700 hover:bg-lime-200 dark:bg-lime-900/30 dark:text-lime-400'
+  },
+  {
+    label: '2.5-Flash-Lite透传',
+    from: 'gemini-2.5-flash-lite',
+    to: 'gemini-2.5-flash-lite',
+    color: 'bg-green-100 text-green-700 hover:bg-green-200 dark:bg-green-900/30 dark:text-green-400'
   }
 ]
 
diff --git a/frontend/src/composables/useModelWhitelist.ts b/frontend/src/composables/useModelWhitelist.ts
index 7779bf26..7df5477c 100644
--- a/frontend/src/composables/useModelWhitelist.ts
+++ b/frontend/src/composables/useModelWhitelist.ts
@@ -291,13 +291,19 @@ const antigravityPresetMappings = [
   { label: 'Sonnet→Sonnet', from: 'claude-sonnet-*', to: 'claude-sonnet-4-5', color: 'bg-indigo-100 text-indigo-700 hover:bg-indigo-200 dark:bg-indigo-900/30 dark:text-indigo-400' },
   { label: 'Opus→Opus', from: 'claude-opus-*', to: 'claude-opus-4-6-thinking', color: 'bg-purple-100 text-purple-700 hover:bg-purple-200 dark:bg-purple-900/30 dark:text-purple-400' },
   { label: 'Haiku→Sonnet', from: 'claude-haiku-*', to: 'claude-sonnet-4-5', color: 'bg-emerald-100 text-emerald-700 hover:bg-emerald-200 dark:bg-emerald-900/30 dark:text-emerald-400' },
-  // Gemini 3 映射
-  { label: '3-Pro-Preview→3-Pro-High', from: 'gemini-3-pro-preview', to: 'gemini-3-pro-high', color: 'bg-amber-100 text-amber-700 hover:bg-amber-200 dark:bg-amber-900/30 dark:text-amber-400' },
-  { label: '3-Pro-High', from: 'gemini-3-pro-high', to: 'gemini-3-pro-high', color: 'bg-orange-100 text-orange-700 hover:bg-orange-200 dark:bg-orange-900/30 dark:text-orange-400' },
-  { label: '3-Pro-Low', from: 'gemini-3-pro-low', to: 'gemini-3-pro-low', color: 'bg-yellow-100 text-yellow-700 hover:bg-yellow-200 dark:bg-yellow-900/30 dark:text-yellow-400' },
+  { label: 'Sonnet4→4.6', from: 'claude-sonnet-4-20250514', to: 'claude-sonnet-4-6', color: 'bg-sky-100 text-sky-700 hover:bg-sky-200 dark:bg-sky-900/30 dark:text-sky-400' },
+  { label: 'Sonnet4.5→4.6', from: 'claude-sonnet-4-5-20250929', to: 'claude-sonnet-4-6', color: 'bg-cyan-100 text-cyan-700 hover:bg-cyan-200 dark:bg-cyan-900/30 dark:text-cyan-400' },
+  { label: 'Sonnet3.5→4.6', from: 'claude-3-5-sonnet-20241022', to: 'claude-sonnet-4-6', color: 'bg-teal-100 text-teal-700 hover:bg-teal-200 dark:bg-teal-900/30 dark:text-teal-400' },
+  { label: 'Opus4.5→4.6', from: 'claude-opus-4-5-20251101', to: 'claude-opus-4-6-thinking', color: 'bg-violet-100 text-violet-700 hover:bg-violet-200 dark:bg-violet-900/30 dark:text-violet-400' },
+  // Gemini 3→3.1 映射
+  { label: '3-Pro-Preview→3.1-Pro-High', from: 'gemini-3-pro-preview', to: 'gemini-3.1-pro-high', color: 'bg-amber-100 text-amber-700 hover:bg-amber-200 dark:bg-amber-900/30 dark:text-amber-400' },
+  { label: '3-Pro-High→3.1-Pro-High', from: 'gemini-3-pro-high', to: 'gemini-3.1-pro-high', color: 'bg-orange-100 text-orange-700 hover:bg-orange-200 dark:bg-orange-900/30 dark:text-orange-400' },
+  { label: '3-Pro-Low→3.1-Pro-Low', from: 'gemini-3-pro-low', to: 'gemini-3.1-pro-low', color: 'bg-yellow-100 text-yellow-700 hover:bg-yellow-200 dark:bg-yellow-900/30 dark:text-yellow-400' },
   // Gemini 通配符映射
   { label: 'Gemini 3→Flash', from: 'gemini-3*', to: 'gemini-3-flash', color: 'bg-yellow-100 text-yellow-700 hover:bg-yellow-200 dark:bg-yellow-900/30 dark:text-yellow-400' },
   { label: 'Gemini 2.5→Flash', from: 'gemini-2.5*', to: 'gemini-2.5-flash', color: 'bg-orange-100 text-orange-700 hover:bg-orange-200 dark:bg-orange-900/30 dark:text-orange-400' },
+  { label: '3-Flash透传', from: 'gemini-3-flash', to: 'gemini-3-flash', color: 'bg-lime-100 text-lime-700 hover:bg-lime-200 dark:bg-lime-900/30 dark:text-lime-400' },
+  { label: '2.5-Flash-Lite透传', from: 'gemini-2.5-flash-lite', to: 'gemini-2.5-flash-lite', color: 'bg-green-100 text-green-700 hover:bg-green-200 dark:bg-green-900/30 dark:text-green-400' },
   // 精确映射
   { label: 'Sonnet 4.6', from: 'claude-sonnet-4-6', to: 'claude-sonnet-4-6', color: 'bg-cyan-100 text-cyan-700 hover:bg-cyan-200 dark:bg-cyan-900/30 dark:text-cyan-400' },
   { label: 'Sonnet 4.5', from: 'claude-sonnet-4-5', to: 'claude-sonnet-4-5', color: 'bg-cyan-100 text-cyan-700 hover:bg-cyan-200 dark:bg-cyan-900/30 dark:text-cyan-400' },