diff --git a/backend/internal/handler/gateway_handler.go b/backend/internal/handler/gateway_handler.go
index 614ded8d..bbc9c181 100644
--- a/backend/internal/handler/gateway_handler.go
+++ b/backend/internal/handler/gateway_handler.go
@@ -1,5 +1,3 @@
-// Package handler provides HTTP request handlers for the API gateway.
-// It handles authentication, request routing, concurrency control, and billing validation.
 package handler
 
 import (
@@ -13,6 +11,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/Wei-Shaw/sub2api/internal/pkg/antigravity"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/claude"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/openai"
 	middleware2 "github.com/Wei-Shaw/sub2api/internal/server/middleware"
@@ -29,7 +28,6 @@ type GatewayHandler struct {
 	userService               *service.UserService
 	billingCacheService       *service.BillingCacheService
 	concurrencyHelper         *ConcurrencyHelper
-	opsService                *service.OpsService
 }
 
 // NewGatewayHandler creates a new GatewayHandler
@@ -40,7 +38,6 @@ func NewGatewayHandler(
 	userService *service.UserService,
 	concurrencyService *service.ConcurrencyService,
 	billingCacheService *service.BillingCacheService,
-	opsService *service.OpsService,
 ) *GatewayHandler {
 	return &GatewayHandler{
 		gatewayService:            gatewayService,
@@ -49,15 +46,14 @@ func NewGatewayHandler(
 		userService:               userService,
 		billingCacheService:       billingCacheService,
 		concurrencyHelper:         NewConcurrencyHelper(concurrencyService, SSEPingFormatClaude),
-		opsService:                opsService,
 	}
 }
 
 // Messages handles Claude API compatible messages endpoint
 // POST /v1/messages
 func (h *GatewayHandler) Messages(c *gin.Context) {
-	// 从context获取apiKey和user（APIKeyAuth中间件已设置）
-	apiKey, ok := middleware2.GetAPIKeyFromContext(c)
+	// 从context获取apiKey和user（ApiKeyAuth中间件已设置）
+	apiKey, ok := middleware2.GetApiKeyFromContext(c)
 	if !ok {
 		h.errorResponse(c, http.StatusUnauthorized, "authentication_error", "Invalid API key")
 		return
@@ -92,7 +88,6 @@ func (h *GatewayHandler) Messages(c *gin.Context) {
 	}
 	reqModel := parsedReq.Model
 	reqStream := parsedReq.Stream
-	setOpsRequestContext(c, reqModel, reqStream)
 
 	// 验证 model 必填
 	if reqModel == "" {
@@ -264,7 +259,7 @@ func (h *GatewayHandler) Messages(c *gin.Context) {
 				defer cancel()
 				if err := h.gatewayService.RecordUsage(ctx, &service.RecordUsageInput{
 					Result:       result,
-					APIKey:       apiKey,
+					ApiKey:       apiKey,
 					User:         apiKey.User,
 					Account:      usedAccount,
 					Subscription: subscription,
@@ -388,7 +383,7 @@ func (h *GatewayHandler) Messages(c *gin.Context) {
 			defer cancel()
 			if err := h.gatewayService.RecordUsage(ctx, &service.RecordUsageInput{
 				Result:       result,
-				APIKey:       apiKey,
+				ApiKey:       apiKey,
 				User:         apiKey.User,
 				Account:      usedAccount,
 				Subscription: subscription,
@@ -405,7 +400,7 @@ func (h *GatewayHandler) Messages(c *gin.Context) {
 // Returns models based on account configurations (model_mapping whitelist)
 // Falls back to default models if no whitelist is configured
 func (h *GatewayHandler) Models(c *gin.Context) {
-	apiKey, _ := middleware2.GetAPIKeyFromContext(c)
+	apiKey, _ := middleware2.GetApiKeyFromContext(c)
 
 	var groupID *int64
 	var platform string
@@ -451,10 +446,19 @@ func (h *GatewayHandler) Models(c *gin.Context) {
 	})
 }
 
+// AntigravityModels 返回 Antigravity 支持的全部模型
+// GET /antigravity/models
+func (h *GatewayHandler) AntigravityModels(c *gin.Context) {
+	c.JSON(http.StatusOK, gin.H{
+		"object": "list",
+		"data":   antigravity.DefaultModels(),
+	})
+}
+
 // Usage handles getting account balance for CC Switch integration
 // GET /v1/usage
 func (h *GatewayHandler) Usage(c *gin.Context) {
-	apiKey, ok := middleware2.GetAPIKeyFromContext(c)
+	apiKey, ok := middleware2.GetApiKeyFromContext(c)
 	if !ok {
 		h.errorResponse(c, http.StatusUnauthorized, "authentication_error", "Invalid API key")
 		return
@@ -579,7 +583,6 @@ func (h *GatewayHandler) mapUpstreamError(statusCode int) (int, string, string)
 // handleStreamingAwareError handles errors that may occur after streaming has started
 func (h *GatewayHandler) handleStreamingAwareError(c *gin.Context, status int, errType, message string, streamStarted bool) {
 	if streamStarted {
-		recordOpsError(c, h.opsService, status, errType, message, "")
 		// Stream already started, send error as SSE event then close
 		flusher, ok := c.Writer.(http.Flusher)
 		if ok {
@@ -611,7 +614,6 @@ func (h *GatewayHandler) handleStreamingAwareError(c *gin.Context, status int, e
 
 // errorResponse 返回Claude API格式的错误响应
 func (h *GatewayHandler) errorResponse(c *gin.Context, status int, errType, message string) {
-	recordOpsError(c, h.opsService, status, errType, message, "")
 	c.JSON(status, gin.H{
 		"type": "error",
 		"error": gin.H{
@@ -625,8 +627,8 @@ func (h *GatewayHandler) errorResponse(c *gin.Context, status int, errType, mess
 // POST /v1/messages/count_tokens
 // 特点：校验订阅/余额，但不计算并发、不记录使用量
 func (h *GatewayHandler) CountTokens(c *gin.Context) {
-	// 从context获取apiKey和user（APIKeyAuth中间件已设置）
-	apiKey, ok := middleware2.GetAPIKeyFromContext(c)
+	// 从context获取apiKey和user（ApiKeyAuth中间件已设置）
+	apiKey, ok := middleware2.GetApiKeyFromContext(c)
 	if !ok {
 		h.errorResponse(c, http.StatusUnauthorized, "authentication_error", "Invalid API key")
 		return
diff --git a/backend/internal/handler/gemini_v1beta_handler.go b/backend/internal/handler/gemini_v1beta_handler.go
index 79ec9950..71678bed 100644
--- a/backend/internal/handler/gemini_v1beta_handler.go
+++ b/backend/internal/handler/gemini_v1beta_handler.go
@@ -9,6 +9,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/Wei-Shaw/sub2api/internal/pkg/antigravity"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/gemini"
 	"github.com/Wei-Shaw/sub2api/internal/pkg/googleapi"
 	"github.com/Wei-Shaw/sub2api/internal/server/middleware"
@@ -20,7 +21,7 @@ import (
 // GeminiV1BetaListModels proxies:
 // GET /v1beta/models
 func (h *GatewayHandler) GeminiV1BetaListModels(c *gin.Context) {
-	apiKey, ok := middleware.GetAPIKeyFromContext(c)
+	apiKey, ok := middleware.GetApiKeyFromContext(c)
 	if !ok || apiKey == nil {
 		googleError(c, http.StatusUnauthorized, "Invalid API key")
 		return
@@ -32,9 +33,9 @@ func (h *GatewayHandler) GeminiV1BetaListModels(c *gin.Context) {
 		return
 	}
 
-	// 强制 antigravity 模式：直接返回静态模型列表
+	// 强制 antigravity 模式：返回 antigravity 支持的模型列表
 	if forcePlatform == service.PlatformAntigravity {
-		c.JSON(http.StatusOK, gemini.FallbackModelsList())
+		c.JSON(http.StatusOK, antigravity.FallbackGeminiModelsList())
 		return
 	}
 
@@ -66,7 +67,7 @@ func (h *GatewayHandler) GeminiV1BetaListModels(c *gin.Context) {
 // GeminiV1BetaGetModel proxies:
 // GET /v1beta/models/{model}
 func (h *GatewayHandler) GeminiV1BetaGetModel(c *gin.Context) {
-	apiKey, ok := middleware.GetAPIKeyFromContext(c)
+	apiKey, ok := middleware.GetApiKeyFromContext(c)
 	if !ok || apiKey == nil {
 		googleError(c, http.StatusUnauthorized, "Invalid API key")
 		return
@@ -84,9 +85,9 @@ func (h *GatewayHandler) GeminiV1BetaGetModel(c *gin.Context) {
 		return
 	}
 
-	// 强制 antigravity 模式：直接返回静态模型信息
+	// 强制 antigravity 模式：返回 antigravity 模型信息
 	if forcePlatform == service.PlatformAntigravity {
-		c.JSON(http.StatusOK, gemini.FallbackModel(modelName))
+		c.JSON(http.StatusOK, antigravity.FallbackGeminiModel(modelName))
 		return
 	}
 
@@ -119,7 +120,7 @@ func (h *GatewayHandler) GeminiV1BetaGetModel(c *gin.Context) {
 // POST /v1beta/models/{model}:generateContent
 // POST /v1beta/models/{model}:streamGenerateContent?alt=sse
 func (h *GatewayHandler) GeminiV1BetaModels(c *gin.Context) {
-	apiKey, ok := middleware.GetAPIKeyFromContext(c)
+	apiKey, ok := middleware.GetApiKeyFromContext(c)
 	if !ok || apiKey == nil {
 		googleError(c, http.StatusUnauthorized, "Invalid API key")
 		return
@@ -298,7 +299,7 @@ func (h *GatewayHandler) GeminiV1BetaModels(c *gin.Context) {
 			defer cancel()
 			if err := h.gatewayService.RecordUsage(ctx, &service.RecordUsageInput{
 				Result:       result,
-				APIKey:       apiKey,
+				ApiKey:       apiKey,
 				User:         apiKey.User,
 				Account:      usedAccount,
 				Subscription: subscription,
diff --git a/backend/internal/pkg/antigravity/claude_types.go b/backend/internal/pkg/antigravity/claude_types.go
index 34e6b1f4..8a29cd10 100644
--- a/backend/internal/pkg/antigravity/claude_types.go
+++ b/backend/internal/pkg/antigravity/claude_types.go
@@ -138,3 +138,91 @@ type ErrorDetail struct {
 	Type    string `json:"type"`
 	Message string `json:"message"`
 }
+
+// modelDef Antigravity 模型定义（内部使用）
+type modelDef struct {
+	ID          string
+	DisplayName string
+	CreatedAt   string // 仅 Claude API 格式使用
+}
+
+// Antigravity 支持的 Claude 模型
+var claudeModels = []modelDef{
+	{ID: "claude-opus-4-5-thinking", DisplayName: "Claude Opus 4.5 Thinking", CreatedAt: "2025-11-01T00:00:00Z"},
+	{ID: "claude-sonnet-4-5", DisplayName: "Claude Sonnet 4.5", CreatedAt: "2025-09-29T00:00:00Z"},
+	{ID: "claude-sonnet-4-5-thinking", DisplayName: "Claude Sonnet 4.5 Thinking", CreatedAt: "2025-09-29T00:00:00Z"},
+}
+
+// Antigravity 支持的 Gemini 模型
+var geminiModels = []modelDef{
+	{ID: "gemini-2.5-flash", DisplayName: "Gemini 2.5 Flash", CreatedAt: "2025-01-01T00:00:00Z"},
+	{ID: "gemini-2.5-flash-lite", DisplayName: "Gemini 2.5 Flash Lite", CreatedAt: "2025-01-01T00:00:00Z"},
+	{ID: "gemini-2.5-flash-thinking", DisplayName: "Gemini 2.5 Flash Thinking", CreatedAt: "2025-01-01T00:00:00Z"},
+	{ID: "gemini-3-flash", DisplayName: "Gemini 3 Flash", CreatedAt: "2025-06-01T00:00:00Z"},
+	{ID: "gemini-3-pro-low", DisplayName: "Gemini 3 Pro Low", CreatedAt: "2025-06-01T00:00:00Z"},
+	{ID: "gemini-3-pro-high", DisplayName: "Gemini 3 Pro High", CreatedAt: "2025-06-01T00:00:00Z"},
+	{ID: "gemini-3-pro-preview", DisplayName: "Gemini 3 Pro Preview", CreatedAt: "2025-06-01T00:00:00Z"},
+	{ID: "gemini-3-pro-image", DisplayName: "Gemini 3 Pro Image", CreatedAt: "2025-06-01T00:00:00Z"},
+}
+
+// ========== Claude API 格式 (/v1/models) ==========
+
+// ClaudeModel Claude API 模型格式
+type ClaudeModel struct {
+	ID          string `json:"id"`
+	Type        string `json:"type"`
+	DisplayName string `json:"display_name"`
+	CreatedAt   string `json:"created_at"`
+}
+
+// DefaultModels 返回 Claude API 格式的模型列表（Claude + Gemini）
+func DefaultModels() []ClaudeModel {
+	all := append(claudeModels, geminiModels...)
+	result := make([]ClaudeModel, len(all))
+	for i, m := range all {
+		result[i] = ClaudeModel{ID: m.ID, Type: "model", DisplayName: m.DisplayName, CreatedAt: m.CreatedAt}
+	}
+	return result
+}
+
+// ========== Gemini v1beta 格式 (/v1beta/models) ==========
+
+// GeminiModel Gemini v1beta 模型格式
+type GeminiModel struct {
+	Name                       string   `json:"name"`
+	DisplayName                string   `json:"displayName,omitempty"`
+	SupportedGenerationMethods []string `json:"supportedGenerationMethods,omitempty"`
+}
+
+// GeminiModelsListResponse Gemini v1beta 模型列表响应
+type GeminiModelsListResponse struct {
+	Models []GeminiModel `json:"models"`
+}
+
+var defaultGeminiMethods = []string{"generateContent", "streamGenerateContent"}
+
+// DefaultGeminiModels 返回 Gemini v1beta 格式的模型列表（仅 Gemini 模型）
+func DefaultGeminiModels() []GeminiModel {
+	result := make([]GeminiModel, len(geminiModels))
+	for i, m := range geminiModels {
+		result[i] = GeminiModel{Name: "models/" + m.ID, DisplayName: m.DisplayName, SupportedGenerationMethods: defaultGeminiMethods}
+	}
+	return result
+}
+
+// FallbackGeminiModelsList 返回 Gemini v1beta 格式的模型列表响应
+func FallbackGeminiModelsList() GeminiModelsListResponse {
+	return GeminiModelsListResponse{Models: DefaultGeminiModels()}
+}
+
+// FallbackGeminiModel 返回单个模型信息（v1beta 格式）
+func FallbackGeminiModel(model string) GeminiModel {
+	if model == "" {
+		return GeminiModel{Name: "models/unknown", SupportedGenerationMethods: defaultGeminiMethods}
+	}
+	name := model
+	if len(model) < 7 || model[:7] != "models/" {
+		name = "models/" + model
+	}
+	return GeminiModel{Name: name, SupportedGenerationMethods: defaultGeminiMethods}
+}
diff --git a/backend/internal/pkg/antigravity/client.go b/backend/internal/pkg/antigravity/client.go
index 90ff34e7..003398bd 100644
--- a/backend/internal/pkg/antigravity/client.go
+++ b/backend/internal/pkg/antigravity/client.go
@@ -1,5 +1,3 @@
-// Package antigravity provides a client for interacting with Google's Antigravity API,
-// handling OAuth authentication, token management, and account tier information retrieval.
 package antigravity
 
 import (
@@ -59,6 +57,29 @@ type TierInfo struct {
 	Description string `json:"description"` // 描述
 }
 
+// UnmarshalJSON supports both legacy string tiers and object tiers.
+func (t *TierInfo) UnmarshalJSON(data []byte) error {
+	data = bytes.TrimSpace(data)
+	if len(data) == 0 || string(data) == "null" {
+		return nil
+	}
+	if data[0] == '"' {
+		var id string
+		if err := json.Unmarshal(data, &id); err != nil {
+			return err
+		}
+		t.ID = id
+		return nil
+	}
+	type alias TierInfo
+	var decoded alias
+	if err := json.Unmarshal(data, &decoded); err != nil {
+		return err
+	}
+	*t = TierInfo(decoded)
+	return nil
+}
+
 // IneligibleTier 不符合条件的层级信息
 type IneligibleTier struct {
 	Tier *TierInfo `json:"tier,omitempty"`
diff --git a/backend/internal/pkg/antigravity/gemini_types.go b/backend/internal/pkg/antigravity/gemini_types.go
index 8e3e3885..67f6c3e7 100644
--- a/backend/internal/pkg/antigravity/gemini_types.go
+++ b/backend/internal/pkg/antigravity/gemini_types.go
@@ -143,9 +143,10 @@ type GeminiCandidate struct {
 
 // GeminiUsageMetadata Gemini 用量元数据
 type GeminiUsageMetadata struct {
-	PromptTokenCount     int `json:"promptTokenCount,omitempty"`
-	CandidatesTokenCount int `json:"candidatesTokenCount,omitempty"`
-	TotalTokenCount      int `json:"totalTokenCount,omitempty"`
+	PromptTokenCount        int `json:"promptTokenCount,omitempty"`
+	CandidatesTokenCount    int `json:"candidatesTokenCount,omitempty"`
+	CachedContentTokenCount int `json:"cachedContentTokenCount,omitempty"`
+	TotalTokenCount         int `json:"totalTokenCount,omitempty"`
 }
 
 // DefaultSafetySettings 默认安全设置（关闭所有过滤）
diff --git a/backend/internal/pkg/antigravity/request_transformer.go b/backend/internal/pkg/antigravity/request_transformer.go
index 3af6579c..9a62ea03 100644
--- a/backend/internal/pkg/antigravity/request_transformer.go
+++ b/backend/internal/pkg/antigravity/request_transformer.go
@@ -150,13 +150,18 @@ func buildContents(messages []ClaudeMessage, toolIDToName map[string]string, isT
 		// 历史 assistant 消息不能添加没有 signature 的 dummy thinking block
 		if allowDummyThought && role == "model" && isThinkingEnabled && i == len(messages)-1 {
 			hasThoughtPart := false
-			for _, p := range parts {
+			firstPartIsThought := false
+			for idx, p := range parts {
 				if p.Thought {
 					hasThoughtPart = true
+					if idx == 0 {
+						firstPartIsThought = true
+					}
 					break
 				}
 			}
-			if !hasThoughtPart && len(parts) > 0 {
+			// 如果没有thinking part，或者有thinking part但不在第一个位置，都需要在开头添加dummy thinking block
+			if len(parts) > 0 && (!hasThoughtPart || !firstPartIsThought) {
 				// 在开头添加 dummy thinking block
 				parts = append([]GeminiPart{{
 					Text:             "Thinking...",
@@ -236,6 +241,7 @@ func buildParts(content json.RawMessage, toolIDToName map[string]string, thought
 			// Claude via Vertex：
 			// - signature 是上游返回的完整性令牌；本地不需要/无法验证，只能透传
 			// - 缺失/无效 signature（例如来自 Gemini 的 dummy signature）会导致上游 400
+			// - 为避免泄露 thinking 内容，缺失/无效 signature 的 thinking 直接丢弃
 			if signature == "" || signature == dummyThoughtSignature {
 				continue
 			}
@@ -429,7 +435,7 @@ func buildTools(tools []ClaudeTool) []GeminiToolDeclaration {
 
 	// 普通工具
 	var funcDecls []GeminiFunctionDecl
-	for i, tool := range tools {
+	for _, tool := range tools {
 		// 跳过无效工具名称
 		if strings.TrimSpace(tool.Name) == "" {
 			log.Printf("Warning: skipping tool with empty name")
@@ -448,10 +454,6 @@ func buildTools(tools []ClaudeTool) []GeminiToolDeclaration {
 			description = tool.Custom.Description
 			inputSchema = tool.Custom.InputSchema
 
-			// 调试日志：记录 custom 工具的 schema
-			if schemaJSON, err := json.Marshal(inputSchema); err == nil {
-				log.Printf("[Debug] Tool[%d] '%s' (custom) original schema: %s", i, tool.Name, string(schemaJSON))
-			}
 		} else {
 			// 标准格式: 从顶层字段获取
 			description = tool.Description
@@ -468,11 +470,6 @@ func buildTools(tools []ClaudeTool) []GeminiToolDeclaration {
 			}
 		}
 
-		// 调试日志：记录清理后的 schema
-		if paramsJSON, err := json.Marshal(params); err == nil {
-			log.Printf("[Debug] Tool[%d] '%s' cleaned schema: %s", i, tool.Name, string(paramsJSON))
-		}
-
 		funcDecls = append(funcDecls, GeminiFunctionDecl{
 			Name:        tool.Name,
 			Description: description,
@@ -627,20 +624,16 @@ func cleanSchemaValue(value any) any {
 			if k == "additionalProperties" {
 				if boolVal, ok := val.(bool); ok {
 					result[k] = boolVal
-					log.Printf("[Debug] additionalProperties is bool: %v", boolVal)
 				} else {
 					// 如果是 schema 对象，转换为 false（更安全的默认值）
 					result[k] = false
-					log.Printf("[Debug] additionalProperties is not bool (type: %T), converting to false", val)
 				}
 				continue
 			}
 
-			// 递归清理所有值
 			result[k] = cleanSchemaValue(val)
 		}
 		return result
-
 	case []any:
 		// 递归处理数组中的每个元素
 		cleaned := make([]any, 0, len(v))
diff --git a/backend/internal/pkg/antigravity/request_transformer_test.go b/backend/internal/pkg/antigravity/request_transformer_test.go
index 845ae033..171ad078 100644
--- a/backend/internal/pkg/antigravity/request_transformer_test.go
+++ b/backend/internal/pkg/antigravity/request_transformer_test.go
@@ -15,15 +15,15 @@ func TestBuildParts_ThinkingBlockWithoutSignature(t *testing.T) {
 		description   string
 	}{
 		{
-			name: "Claude model - skip thinking block without signature",
+			name: "Claude model - drop thinking without signature",
 			content: `[
 				{"type": "text", "text": "Hello"},
 				{"type": "thinking", "thinking": "Let me think...", "signature": ""},
 				{"type": "text", "text": "World"}
 			]`,
 			thoughtMode:   thoughtSignatureModePreserve,
-			expectedParts: 2, // 只有两个text block
-			description:   "Claude模型应该跳过无signature的thinking block",
+			expectedParts: 2, // thinking 内容被丢弃
+			description:   "Claude模型应丢弃无signature的thinking block内容",
 		},
 		{
 			name: "Claude model - preserve thinking block with signature",
diff --git a/backend/internal/pkg/antigravity/response_transformer.go b/backend/internal/pkg/antigravity/response_transformer.go
index 799de694..9f63c958 100644
--- a/backend/internal/pkg/antigravity/response_transformer.go
+++ b/backend/internal/pkg/antigravity/response_transformer.go
@@ -232,10 +232,18 @@ func (p *NonStreamingProcessor) buildResponse(geminiResp *GeminiResponse, respon
 		stopReason = "max_tokens"
 	}
 
+	// 注意：Gemini 的 promptTokenCount 包含 cachedContentTokenCount，
+	// 但 Claude 的 input_tokens 不包含 cache_read_input_tokens，需要减去
 	usage := ClaudeUsage{}
 	if geminiResp.UsageMetadata != nil {
-		usage.InputTokens = geminiResp.UsageMetadata.PromptTokenCount
+		cached := geminiResp.UsageMetadata.CachedContentTokenCount
+		prompt := geminiResp.UsageMetadata.PromptTokenCount
+		if cached > prompt {
+			cached = prompt
+		}
+		usage.InputTokens = prompt - cached
 		usage.OutputTokens = geminiResp.UsageMetadata.CandidatesTokenCount
+		usage.CacheReadInputTokens = cached
 	}
 
 	// 生成响应 ID
diff --git a/backend/internal/pkg/antigravity/stream_transformer.go b/backend/internal/pkg/antigravity/stream_transformer.go
index c5d954f5..acb33354 100644
--- a/backend/internal/pkg/antigravity/stream_transformer.go
+++ b/backend/internal/pkg/antigravity/stream_transformer.go
@@ -29,8 +29,9 @@ type StreamingProcessor struct {
 	originalModel     string
 
 	// 累计 usage
-	inputTokens  int
-	outputTokens int
+	inputTokens     int
+	outputTokens    int
+	cacheReadTokens int
 }
 
 // NewStreamingProcessor 创建流式响应处理器
@@ -76,9 +77,17 @@ func (p *StreamingProcessor) ProcessLine(line string) []byte {
 	}
 
 	// 更新 usage
+	// 注意：Gemini 的 promptTokenCount 包含 cachedContentTokenCount，
+	// 但 Claude 的 input_tokens 不包含 cache_read_input_tokens，需要减去
 	if geminiResp.UsageMetadata != nil {
-		p.inputTokens = geminiResp.UsageMetadata.PromptTokenCount
+		cached := geminiResp.UsageMetadata.CachedContentTokenCount
+		prompt := geminiResp.UsageMetadata.PromptTokenCount
+		if cached > prompt {
+			cached = prompt
+		}
+		p.inputTokens = prompt - cached
 		p.outputTokens = geminiResp.UsageMetadata.CandidatesTokenCount
+		p.cacheReadTokens = cached
 	}
 
 	// 处理 parts
@@ -108,8 +117,9 @@ func (p *StreamingProcessor) Finish() ([]byte, *ClaudeUsage) {
 	}
 
 	usage := &ClaudeUsage{
-		InputTokens:  p.inputTokens,
-		OutputTokens: p.outputTokens,
+		InputTokens:          p.inputTokens,
+		OutputTokens:         p.outputTokens,
+		CacheReadInputTokens: p.cacheReadTokens,
 	}
 
 	return result.Bytes(), usage
@@ -123,8 +133,14 @@ func (p *StreamingProcessor) emitMessageStart(v1Resp *V1InternalResponse) []byte
 
 	usage := ClaudeUsage{}
 	if v1Resp.Response.UsageMetadata != nil {
-		usage.InputTokens = v1Resp.Response.UsageMetadata.PromptTokenCount
+		cached := v1Resp.Response.UsageMetadata.CachedContentTokenCount
+		prompt := v1Resp.Response.UsageMetadata.PromptTokenCount
+		if cached > prompt {
+			cached = prompt
+		}
+		usage.InputTokens = prompt - cached
 		usage.OutputTokens = v1Resp.Response.UsageMetadata.CandidatesTokenCount
+		usage.CacheReadInputTokens = cached
 	}
 
 	responseID := v1Resp.ResponseID
@@ -418,8 +434,9 @@ func (p *StreamingProcessor) emitFinish(finishReason string) []byte {
 	}
 
 	usage := ClaudeUsage{
-		InputTokens:  p.inputTokens,
-		OutputTokens: p.outputTokens,
+		InputTokens:          p.inputTokens,
+		OutputTokens:         p.outputTokens,
+		CacheReadInputTokens: p.cacheReadTokens,
 	}
 
 	deltaEvent := map[string]any{
diff --git a/backend/internal/server/routes/gateway.go b/backend/internal/server/routes/gateway.go
index d9e0bb81..941f1ce9 100644
--- a/backend/internal/server/routes/gateway.go
+++ b/backend/internal/server/routes/gateway.go
@@ -13,8 +13,8 @@ import (
 func RegisterGatewayRoutes(
 	r *gin.Engine,
 	h *handler.Handlers,
-	apiKeyAuth middleware.APIKeyAuthMiddleware,
-	apiKeyService *service.APIKeyService,
+	apiKeyAuth middleware.ApiKeyAuthMiddleware,
+	apiKeyService *service.ApiKeyService,
 	subscriptionService *service.SubscriptionService,
 	cfg *config.Config,
 ) {
@@ -36,7 +36,7 @@ func RegisterGatewayRoutes(
 	// Gemini 原生 API 兼容层（Gemini SDK/CLI 直连）
 	gemini := r.Group("/v1beta")
 	gemini.Use(bodyLimit)
-	gemini.Use(middleware.APIKeyAuthWithSubscriptionGoogle(apiKeyService, subscriptionService, cfg))
+	gemini.Use(middleware.ApiKeyAuthWithSubscriptionGoogle(apiKeyService, subscriptionService, cfg))
 	{
 		gemini.GET("/models", h.Gateway.GeminiV1BetaListModels)
 		gemini.GET("/models/:model", h.Gateway.GeminiV1BetaGetModel)
@@ -47,6 +47,9 @@ func RegisterGatewayRoutes(
 	// OpenAI Responses API（不带v1前缀的别名）
 	r.POST("/responses", bodyLimit, gin.HandlerFunc(apiKeyAuth), h.OpenAIGateway.Responses)
 
+	// Antigravity 模型列表
+	r.GET("/antigravity/models", gin.HandlerFunc(apiKeyAuth), h.Gateway.AntigravityModels)
+
 	// Antigravity 专用路由（仅使用 antigravity 账户，不混合调度）
 	antigravityV1 := r.Group("/antigravity/v1")
 	antigravityV1.Use(bodyLimit)
@@ -55,14 +58,14 @@ func RegisterGatewayRoutes(
 	{
 		antigravityV1.POST("/messages", h.Gateway.Messages)
 		antigravityV1.POST("/messages/count_tokens", h.Gateway.CountTokens)
-		antigravityV1.GET("/models", h.Gateway.Models)
+		antigravityV1.GET("/models", h.Gateway.AntigravityModels)
 		antigravityV1.GET("/usage", h.Gateway.Usage)
 	}
 
 	antigravityV1Beta := r.Group("/antigravity/v1beta")
 	antigravityV1Beta.Use(bodyLimit)
 	antigravityV1Beta.Use(middleware.ForcePlatform(service.PlatformAntigravity))
-	antigravityV1Beta.Use(middleware.APIKeyAuthWithSubscriptionGoogle(apiKeyService, subscriptionService, cfg))
+	antigravityV1Beta.Use(middleware.ApiKeyAuthWithSubscriptionGoogle(apiKeyService, subscriptionService, cfg))
 	{
 		antigravityV1Beta.GET("/models", h.Gateway.GeminiV1BetaListModels)
 		antigravityV1Beta.GET("/models/:model", h.Gateway.GeminiV1BetaGetModel)
diff --git a/backend/internal/service/antigravity_gateway_service.go b/backend/internal/service/antigravity_gateway_service.go
index be908189..5f398740 100644
--- a/backend/internal/service/antigravity_gateway_service.go
+++ b/backend/internal/service/antigravity_gateway_service.go
@@ -49,11 +49,11 @@ var antigravityPrefixMapping = []struct {
 	{"gemini-3-pro-image", "gemini-3-pro-image"}, // gemini-3-pro-image-preview 等
 	{"claude-3-5-sonnet", "claude-sonnet-4-5"},   // 旧版 claude-3-5-sonnet-xxx
 	{"claude-sonnet-4-5", "claude-sonnet-4-5"},   // claude-sonnet-4-5-xxx
-	{"claude-haiku-4-5", "gemini-3-flash"},       // claude-haiku-4-5-xxx
+	{"claude-haiku-4-5", "claude-sonnet-4-5"},    // claude-haiku-4-5-xxx → sonnet
 	{"claude-opus-4-5", "claude-opus-4-5-thinking"},
-	{"claude-3-haiku", "gemini-3-flash"}, // 旧版 claude-3-haiku-xxx
+	{"claude-3-haiku", "claude-sonnet-4-5"}, // 旧版 claude-3-haiku-xxx → sonnet
 	{"claude-sonnet-4", "claude-sonnet-4-5"},
-	{"claude-haiku-4", "gemini-3-flash"},
+	{"claude-haiku-4", "claude-sonnet-4-5"}, // → sonnet
 	{"claude-opus-4", "claude-opus-4-5-thinking"},
 	{"gemini-3-pro", "gemini-3-pro-high"}, // gemini-3-pro, gemini-3-pro-preview 等
 }
@@ -64,6 +64,7 @@ type AntigravityGatewayService struct {
 	tokenProvider    *AntigravityTokenProvider
 	rateLimitService *RateLimitService
 	httpUpstream     HTTPUpstream
+	settingService   *SettingService
 }
 
 func NewAntigravityGatewayService(
@@ -72,12 +73,14 @@ func NewAntigravityGatewayService(
 	tokenProvider *AntigravityTokenProvider,
 	rateLimitService *RateLimitService,
 	httpUpstream HTTPUpstream,
+	settingService *SettingService,
 ) *AntigravityGatewayService {
 	return &AntigravityGatewayService{
 		accountRepo:      accountRepo,
 		tokenProvider:    tokenProvider,
 		rateLimitService: rateLimitService,
 		httpUpstream:     httpUpstream,
+		settingService:   settingService,
 	}
 }
 
@@ -308,6 +311,7 @@ func (s *AntigravityGatewayService) unwrapV1InternalResponse(body []byte) ([]byt
 }
 
 // isSignatureRelatedError 检测是否为 signature 相关的 400 错误
+// 注意：不包含 "thinking" 关键词，避免误判消息格式错误为 signature 错误
 func isSignatureRelatedError(statusCode int, body []byte) bool {
 	if statusCode != 400 {
 		return false
@@ -318,7 +322,6 @@ func isSignatureRelatedError(statusCode int, body []byte) bool {
 		"signature",
 		"thought_signature",
 		"thoughtsignature",
-		"thinking",
 		"invalid signature",
 		"signature validation",
 	}
@@ -331,28 +334,60 @@ func isSignatureRelatedError(statusCode int, body []byte) bool {
 	return false
 }
 
-// stripThinkingFromClaudeRequest 从 Claude 请求中移除所有 thinking 相关内容
+// isModelNotFoundError 检测是否为模型不存在的 404 错误
+func isModelNotFoundError(statusCode int, body []byte) bool {
+	if statusCode != 404 {
+		return false
+	}
+
+	bodyStr := strings.ToLower(string(body))
+	keywords := []string{
+		"model not found",
+		"model does not exist",
+		"unknown model",
+		"invalid model",
+	}
+
+	for _, keyword := range keywords {
+		if strings.Contains(bodyStr, keyword) {
+			return true
+		}
+	}
+	return false
+}
+
+// stripThinkingFromClaudeRequest 从 Claude 请求中移除有问题的 thinking 块
+// 策略：只移除历史消息中带 dummy signature 的 thinking 块，保留本次 thinking 配置
+// 这样可以让本次对话仍然使用 thinking 功能，只是清理历史中可能导致问题的内容
 func stripThinkingFromClaudeRequest(req *antigravity.ClaudeRequest) *antigravity.ClaudeRequest {
 	// 创建副本
 	stripped := *req
 
-	// 移除 thinking 配置
-	stripped.Thinking = nil
+	// 保留 thinking 配置，让本次对话仍然可以使用 thinking
+	// stripped.Thinking = nil  // 不再移除
 
-	// 移除消息中的 thinking 块
+	// 只移除消息中带 dummy signature 的 thinking 块
 	if len(stripped.Messages) > 0 {
 		newMessages := make([]antigravity.ClaudeMessage, 0, len(stripped.Messages))
 		for _, msg := range stripped.Messages {
 			newMsg := msg
 
-			// 如果 content 是数组，过滤 thinking 块
+			// 如果 content 是数组，过滤有问题的 thinking 块
 			var blocks []map[string]any
 			if err := json.Unmarshal(msg.Content, &blocks); err == nil {
 				filtered := make([]map[string]any, 0, len(blocks))
 				for _, block := range blocks {
-					// 跳过有 type="thinking" 的块
+					// 跳过带 dummy signature 的 thinking 块
 					if blockType, ok := block["type"].(string); ok && blockType == "thinking" {
-						continue
+						if sig, ok := block["signature"].(string); ok {
+							// 移除 dummy signature 的 thinking 块
+							if sig == "skip_thought_signature_validator" || sig == "" {
+								continue
+							}
+						} else {
+							// 没有 signature 字段的 thinking 块也移除
+							continue
+						}
 					}
 					// 跳过没有 type 但有 thinking 字段的块（untyped thinking blocks）
 					if _, hasType := block["type"]; !hasType {
@@ -390,9 +425,6 @@ func (s *AntigravityGatewayService) Forward(ctx context.Context, c *gin.Context,
 
 	originalModel := claudeReq.Model
 	mappedModel := s.getMappedModel(account, claudeReq.Model)
-	if mappedModel != claudeReq.Model {
-		log.Printf("Antigravity model mapping: %s -> %s (account: %s)", claudeReq.Model, mappedModel, account.Name)
-	}
 
 	// 获取 access_token
 	if s.tokenProvider == nil {
@@ -418,15 +450,6 @@ func (s *AntigravityGatewayService) Forward(ctx context.Context, c *gin.Context,
 		return nil, fmt.Errorf("transform request: %w", err)
 	}
 
-	// 调试：记录转换后的请求体（仅记录前 2000 字符）
-	if bodyJSON, err := json.Marshal(geminiBody); err == nil {
-		truncated := string(bodyJSON)
-		if len(truncated) > 2000 {
-			truncated = truncated[:2000] + "..."
-		}
-		log.Printf("[Debug] Transformed Gemini request: %s", truncated)
-	}
-
 	// 构建上游 action
 	action := "generateContent"
 	if claudeReq.Stream {
@@ -495,7 +518,7 @@ func (s *AntigravityGatewayService) Forward(ctx context.Context, c *gin.Context,
 			if err != nil {
 				log.Printf("[Antigravity] Failed to transform stripped request: %v", err)
 				// 降级失败，返回原始错误
-				if s.shouldFailoverUpstreamError(resp.StatusCode) {
+				if s.shouldFailoverWithTempUnsched(ctx, account, resp.StatusCode, respBody) {
 					return nil, &UpstreamFailoverError{StatusCode: resp.StatusCode}
 				}
 				return nil, s.writeMappedClaudeError(c, resp.StatusCode, respBody)
@@ -505,7 +528,7 @@ func (s *AntigravityGatewayService) Forward(ctx context.Context, c *gin.Context,
 			retryReq, err := antigravity.NewAPIRequest(ctx, action, accessToken, strippedBody)
 			if err != nil {
 				log.Printf("[Antigravity] Failed to create retry request: %v", err)
-				if s.shouldFailoverUpstreamError(resp.StatusCode) {
+				if s.shouldFailoverWithTempUnsched(ctx, account, resp.StatusCode, respBody) {
 					return nil, &UpstreamFailoverError{StatusCode: resp.StatusCode}
 				}
 				return nil, s.writeMappedClaudeError(c, resp.StatusCode, respBody)
@@ -514,7 +537,7 @@ func (s *AntigravityGatewayService) Forward(ctx context.Context, c *gin.Context,
 			retryResp, err := s.httpUpstream.Do(retryReq, proxyURL, account.ID, account.Concurrency)
 			if err != nil {
 				log.Printf("[Antigravity] Retry request failed: %v", err)
-				if s.shouldFailoverUpstreamError(resp.StatusCode) {
+				if s.shouldFailoverWithTempUnsched(ctx, account, resp.StatusCode, respBody) {
 					return nil, &UpstreamFailoverError{StatusCode: resp.StatusCode}
 				}
 				return nil, s.writeMappedClaudeError(c, resp.StatusCode, respBody)
@@ -531,7 +554,7 @@ func (s *AntigravityGatewayService) Forward(ctx context.Context, c *gin.Context,
 				log.Printf("[Antigravity] Retry also failed with status %d: %s", retryResp.StatusCode, string(retryRespBody))
 				s.handleUpstreamError(ctx, account, retryResp.StatusCode, retryResp.Header, retryRespBody)
 
-				if s.shouldFailoverUpstreamError(retryResp.StatusCode) {
+				if s.shouldFailoverWithTempUnsched(ctx, account, retryResp.StatusCode, retryRespBody) {
 					return nil, &UpstreamFailoverError{StatusCode: retryResp.StatusCode}
 				}
 				return nil, s.writeMappedClaudeError(c, retryResp.StatusCode, retryRespBody)
@@ -540,7 +563,7 @@ func (s *AntigravityGatewayService) Forward(ctx context.Context, c *gin.Context,
 
 		// 不是 signature 错误，或者已经没有 thinking 块，直接返回错误
 		if resp.StatusCode >= 400 {
-			if s.shouldFailoverUpstreamError(resp.StatusCode) {
+			if s.shouldFailoverWithTempUnsched(ctx, account, resp.StatusCode, respBody) {
 				return nil, &UpstreamFailoverError{StatusCode: resp.StatusCode}
 			}
 
@@ -594,8 +617,10 @@ func (s *AntigravityGatewayService) ForwardGemini(ctx context.Context, c *gin.Co
 	}
 
 	switch action {
-	case "generateContent", "streamGenerateContent", "countTokens":
+	case "generateContent", "streamGenerateContent":
 		// ok
+	case "countTokens":
+		return nil, s.writeGoogleError(c, http.StatusNotImplemented, "countTokens is not supported")
 	default:
 		return nil, s.writeGoogleError(c, http.StatusNotFound, "Unsupported action: "+action)
 	}
@@ -650,18 +675,6 @@ func (s *AntigravityGatewayService) ForwardGemini(ctx context.Context, c *gin.Co
 				sleepAntigravityBackoff(attempt)
 				continue
 			}
-			if action == "countTokens" {
-				estimated := estimateGeminiCountTokens(body)
-				c.JSON(http.StatusOK, map[string]any{"totalTokens": estimated})
-				return &ForwardResult{
-					RequestID:    "",
-					Usage:        ClaudeUsage{},
-					Model:        originalModel,
-					Stream:       false,
-					Duration:     time.Since(startTime),
-					FirstTokenMs: nil,
-				}, nil
-			}
 			return nil, s.writeGoogleError(c, http.StatusBadGateway, "Upstream request failed after retries")
 		}
 
@@ -678,18 +691,6 @@ func (s *AntigravityGatewayService) ForwardGemini(ctx context.Context, c *gin.Co
 			if resp.StatusCode == 429 {
 				s.handleUpstreamError(ctx, account, resp.StatusCode, resp.Header, respBody)
 			}
-			if action == "countTokens" {
-				estimated := estimateGeminiCountTokens(body)
-				c.JSON(http.StatusOK, map[string]any{"totalTokens": estimated})
-				return &ForwardResult{
-					RequestID:    "",
-					Usage:        ClaudeUsage{},
-					Model:        originalModel,
-					Stream:       false,
-					Duration:     time.Since(startTime),
-					FirstTokenMs: nil,
-				}, nil
-			}
 			resp = &http.Response{
 				StatusCode: resp.StatusCode,
 				Header:     resp.Header.Clone(),
@@ -712,20 +713,42 @@ func (s *AntigravityGatewayService) ForwardGemini(ctx context.Context, c *gin.Co
 		respBody, _ := io.ReadAll(io.LimitReader(resp.Body, 2<<20))
 		s.handleUpstreamError(ctx, account, resp.StatusCode, resp.Header, respBody)
 
-		if action == "countTokens" {
-			estimated := estimateGeminiCountTokens(body)
-			c.JSON(http.StatusOK, map[string]any{"totalTokens": estimated})
-			return &ForwardResult{
-				RequestID:    requestID,
-				Usage:        ClaudeUsage{},
-				Model:        originalModel,
-				Stream:       false,
-				Duration:     time.Since(startTime),
-				FirstTokenMs: nil,
-			}, nil
+		// Check if model fallback is enabled and this is a model not found error
+		if s.settingService != nil && s.settingService.IsModelFallbackEnabled(ctx) &&
+			isModelNotFoundError(resp.StatusCode, respBody) {
+
+			fallbackModel := s.settingService.GetFallbackModel(ctx, PlatformAntigravity)
+
+			// Only retry if fallback model is different from current model
+			if fallbackModel != "" && fallbackModel != mappedModel {
+				log.Printf("[Antigravity] Model not found (%s), retrying with fallback model %s (account: %s)",
+					mappedModel, fallbackModel, account.Name)
+
+				// Close original response
+				_ = resp.Body.Close()
+
+				// Rebuild request with fallback model
+				fallbackBody, err := s.wrapV1InternalRequest(projectID, fallbackModel, body)
+				if err == nil {
+					fallbackReq, err := antigravity.NewAPIRequest(ctx, upstreamAction, accessToken, fallbackBody)
+					if err == nil {
+						fallbackResp, err := s.httpUpstream.Do(fallbackReq, proxyURL, account.ID, account.Concurrency)
+						if err == nil && fallbackResp.StatusCode < 400 {
+							log.Printf("[Antigravity] Fallback succeeded with %s (account: %s)", fallbackModel, account.Name)
+							resp = fallbackResp
+							originalModel = fallbackModel // Update for billing
+							// Continue to normal response handling
+							goto handleSuccess
+						} else if fallbackResp != nil {
+							_ = fallbackResp.Body.Close()
+						}
+					}
+				}
+				log.Printf("[Antigravity] Fallback failed, returning original error")
+			}
 		}
 
-		if s.shouldFailoverUpstreamError(resp.StatusCode) {
+		if s.shouldFailoverWithTempUnsched(ctx, account, resp.StatusCode, respBody) {
 			return nil, &UpstreamFailoverError{StatusCode: resp.StatusCode}
 		}
 
@@ -739,6 +762,7 @@ func (s *AntigravityGatewayService) ForwardGemini(ctx context.Context, c *gin.Co
 		return nil, fmt.Errorf("antigravity upstream error: %d", resp.StatusCode)
 	}
 
+handleSuccess:
 	var usage *ClaudeUsage
 	var firstTokenMs *int
 
@@ -789,6 +813,15 @@ func (s *AntigravityGatewayService) shouldFailoverUpstreamError(statusCode int)
 	}
 }
 
+func (s *AntigravityGatewayService) shouldFailoverWithTempUnsched(ctx context.Context, account *Account, statusCode int, body []byte) bool {
+	if s.rateLimitService != nil {
+		if s.rateLimitService.HandleTempUnschedulable(ctx, account, statusCode, body) {
+			return true
+		}
+	}
+	return s.shouldFailoverUpstreamError(statusCode)
+}
+
 func sleepAntigravityBackoff(attempt int) {
 	sleepGeminiBackoff(attempt) // 复用 Gemini 的退避逻辑
 }
@@ -899,7 +932,10 @@ func (s *AntigravityGatewayService) handleGeminiNonStreamingResponse(c *gin.Cont
 	}
 
 	// 解包 v1internal 响应
-	unwrapped, _ := s.unwrapV1InternalResponse(respBody)
+	unwrapped := respBody
+	if inner, unwrapErr := s.unwrapV1InternalResponse(respBody); unwrapErr == nil && inner != nil {
+		unwrapped = inner
+	}
 
 	var parsed map[string]any
 	if json.Unmarshal(unwrapped, &parsed) == nil {
@@ -973,6 +1009,8 @@ func (s *AntigravityGatewayService) writeGoogleError(c *gin.Context, status int,
 		statusStr = "RESOURCE_EXHAUSTED"
 	case 500:
 		statusStr = "INTERNAL"
+	case 501:
+		statusStr = "UNIMPLEMENTED"
 	case 502, 503:
 		statusStr = "UNAVAILABLE"
 	}
diff --git a/backend/internal/service/antigravity_model_mapping_test.go b/backend/internal/service/antigravity_model_mapping_test.go
index 1e37cdc2..39000e4f 100644
--- a/backend/internal/service/antigravity_model_mapping_test.go
+++ b/backend/internal/service/antigravity_model_mapping_test.go
@@ -104,28 +104,28 @@ func TestAntigravityGatewayService_GetMappedModel(t *testing.T) {
 			expected:       "claude-opus-4-5-thinking",
 		},
 		{
-			name:           "系统映射 - claude-haiku-4 → gemini-3-flash",
+			name:           "系统映射 - claude-haiku-4 → claude-sonnet-4-5",
 			requestedModel: "claude-haiku-4",
 			accountMapping: nil,
-			expected:       "gemini-3-flash",
+			expected:       "claude-sonnet-4-5",
 		},
 		{
-			name:           "系统映射 - claude-haiku-4-5 → gemini-3-flash",
+			name:           "系统映射 - claude-haiku-4-5 → claude-sonnet-4-5",
 			requestedModel: "claude-haiku-4-5",
 			accountMapping: nil,
-			expected:       "gemini-3-flash",
+			expected:       "claude-sonnet-4-5",
 		},
 		{
-			name:           "系统映射 - claude-3-haiku-20240307 → gemini-3-flash",
+			name:           "系统映射 - claude-3-haiku-20240307 → claude-sonnet-4-5",
 			requestedModel: "claude-3-haiku-20240307",
 			accountMapping: nil,
-			expected:       "gemini-3-flash",
+			expected:       "claude-sonnet-4-5",
 		},
 		{
-			name:           "系统映射 - claude-haiku-4-5-20251001 → gemini-3-flash",
+			name:           "系统映射 - claude-haiku-4-5-20251001 → claude-sonnet-4-5",
 			requestedModel: "claude-haiku-4-5-20251001",
 			accountMapping: nil,
-			expected:       "gemini-3-flash",
+			expected:       "claude-sonnet-4-5",
 		},
 		{
 			name:           "系统映射 - claude-sonnet-4-5-20250929",
diff --git a/backend/internal/service/antigravity_quota_fetcher.go b/backend/internal/service/antigravity_quota_fetcher.go
new file mode 100644
index 00000000..c0231e99
--- /dev/null
+++ b/backend/internal/service/antigravity_quota_fetcher.go
@@ -0,0 +1,134 @@
+package service
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/Wei-Shaw/sub2api/internal/pkg/antigravity"
+)
+
+// AntigravityQuotaFetcher 从 Antigravity API 获取额度
+type AntigravityQuotaFetcher struct {
+	proxyRepo ProxyRepository
+}
+
+// NewAntigravityQuotaFetcher 创建 AntigravityQuotaFetcher
+func NewAntigravityQuotaFetcher(proxyRepo ProxyRepository) *AntigravityQuotaFetcher {
+	return &AntigravityQuotaFetcher{proxyRepo: proxyRepo}
+}
+
+// CanFetch 检查是否可以获取此账户的额度
+func (f *AntigravityQuotaFetcher) CanFetch(account *Account) bool {
+	if f == nil || account == nil {
+		return false
+	}
+	if account.Platform != PlatformAntigravity {
+		return false
+	}
+	accessToken := account.GetCredential("access_token")
+	return accessToken != ""
+}
+
+// FetchQuota 获取 Antigravity 账户额度信息
+func (f *AntigravityQuotaFetcher) FetchQuota(ctx context.Context, account *Account, proxyURL string) (*QuotaResult, error) {
+	if f == nil {
+		return nil, fmt.Errorf("antigravity quota fetcher is nil")
+	}
+	if account == nil {
+		return nil, fmt.Errorf("account is nil")
+	}
+	accessToken := account.GetCredential("access_token")
+	projectID := account.GetCredential("project_id")
+
+	// 如果没有 project_id，生成一个随机的
+	if projectID == "" {
+		projectID = antigravity.GenerateMockProjectID()
+	}
+
+	client := antigravity.NewClient(proxyURL)
+
+	// 调用 API 获取配额
+	modelsResp, modelsRaw, err := client.FetchAvailableModels(ctx, accessToken, projectID)
+	if err != nil {
+		return nil, err
+	}
+
+	// 转换为 UsageInfo
+	usageInfo := f.buildUsageInfo(modelsResp)
+
+	return &QuotaResult{
+		UsageInfo: usageInfo,
+		Raw:       modelsRaw,
+	}, nil
+}
+
+// buildUsageInfo 将 API 响应转换为 UsageInfo
+func (f *AntigravityQuotaFetcher) buildUsageInfo(modelsResp *antigravity.FetchAvailableModelsResponse) *UsageInfo {
+	now := time.Now()
+	info := &UsageInfo{
+		UpdatedAt:        &now,
+		AntigravityQuota: make(map[string]*AntigravityModelQuota),
+	}
+
+	if modelsResp == nil {
+		return info
+	}
+
+	// 遍历所有模型，填充 AntigravityQuota
+	for modelName, modelInfo := range modelsResp.Models {
+		if modelInfo.QuotaInfo == nil {
+			continue
+		}
+
+		// remainingFraction 是剩余比例 (0.0-1.0)，转换为使用率百分比
+		utilization := clampInt(int((1.0-modelInfo.QuotaInfo.RemainingFraction)*100), 0, 100)
+
+		info.AntigravityQuota[modelName] = &AntigravityModelQuota{
+			Utilization: utilization,
+			ResetTime:   modelInfo.QuotaInfo.ResetTime,
+		}
+	}
+
+	// 同时设置 FiveHour 用于兼容展示（取主要模型）
+	priorityModels := []string{"claude-sonnet-4-20250514", "claude-sonnet-4", "gemini-2.5-pro"}
+	for _, modelName := range priorityModels {
+		if modelInfo, ok := modelsResp.Models[modelName]; ok && modelInfo.QuotaInfo != nil {
+			utilization := clampFloat64((1.0-modelInfo.QuotaInfo.RemainingFraction)*100, 0, 100)
+			progress := &UsageProgress{
+				Utilization: utilization,
+			}
+			if modelInfo.QuotaInfo.ResetTime != "" {
+				if resetTime, err := time.Parse(time.RFC3339, modelInfo.QuotaInfo.ResetTime); err == nil {
+					progress.ResetsAt = &resetTime
+					progress.RemainingSeconds = remainingSecondsUntil(resetTime)
+				}
+			}
+			info.FiveHour = progress
+			break
+		}
+	}
+
+	return info
+}
+
+// GetProxyURL 获取账户的代理 URL
+func (f *AntigravityQuotaFetcher) GetProxyURL(ctx context.Context, account *Account) (string, error) {
+	if f == nil {
+		return "", fmt.Errorf("antigravity quota fetcher is nil")
+	}
+	if account == nil {
+		return "", fmt.Errorf("account is nil")
+	}
+	if account.ProxyID == nil || f.proxyRepo == nil {
+		return "", nil
+	}
+	proxy, err := f.proxyRepo.GetByID(ctx, *account.ProxyID)
+	if err != nil {
+		return "", err
+	}
+	if proxy == nil {
+		return "", nil
+	}
+	return proxy.URL(), nil
+}
diff --git a/backend/internal/service/antigravity_quota_refresher.go b/backend/internal/service/antigravity_quota_refresher.go
deleted file mode 100644
index c4b11d73..00000000
--- a/backend/internal/service/antigravity_quota_refresher.go
+++ /dev/null
@@ -1,222 +0,0 @@
-package service
-
-import (
-	"context"
-	"log"
-	"sync"
-	"time"
-
-	"github.com/Wei-Shaw/sub2api/internal/config"
-	"github.com/Wei-Shaw/sub2api/internal/pkg/antigravity"
-)
-
-// AntigravityQuotaRefresher 定时刷新 Antigravity 账户的配额信息
-type AntigravityQuotaRefresher struct {
-	accountRepo AccountRepository
-	proxyRepo   ProxyRepository
-	cfg         *config.TokenRefreshConfig
-
-	stopCh chan struct{}
-	wg     sync.WaitGroup
-}
-
-// NewAntigravityQuotaRefresher 创建配额刷新器
-func NewAntigravityQuotaRefresher(
-	accountRepo AccountRepository,
-	proxyRepo ProxyRepository,
-	_ *AntigravityOAuthService,
-	cfg *config.Config,
-) *AntigravityQuotaRefresher {
-	return &AntigravityQuotaRefresher{
-		accountRepo: accountRepo,
-		proxyRepo:   proxyRepo,
-		cfg:         &cfg.TokenRefresh,
-		stopCh:      make(chan struct{}),
-	}
-}
-
-// Start 启动后台配额刷新服务
-func (r *AntigravityQuotaRefresher) Start() {
-	if !r.cfg.Enabled {
-		log.Println("[AntigravityQuota] Service disabled by configuration")
-		return
-	}
-
-	r.wg.Add(1)
-	go r.refreshLoop()
-
-	log.Printf("[AntigravityQuota] Service started (check every %d minutes)", r.cfg.CheckIntervalMinutes)
-}
-
-// Stop 停止服务
-func (r *AntigravityQuotaRefresher) Stop() {
-	close(r.stopCh)
-	r.wg.Wait()
-	log.Println("[AntigravityQuota] Service stopped")
-}
-
-// refreshLoop 刷新循环
-func (r *AntigravityQuotaRefresher) refreshLoop() {
-	defer r.wg.Done()
-
-	checkInterval := time.Duration(r.cfg.CheckIntervalMinutes) * time.Minute
-	if checkInterval < time.Minute {
-		checkInterval = 5 * time.Minute
-	}
-
-	ticker := time.NewTicker(checkInterval)
-	defer ticker.Stop()
-
-	// 启动时立即执行一次
-	r.processRefresh()
-
-	for {
-		select {
-		case <-ticker.C:
-			r.processRefresh()
-		case <-r.stopCh:
-			return
-		}
-	}
-}
-
-// processRefresh 执行一次刷新
-func (r *AntigravityQuotaRefresher) processRefresh() {
-	ctx := context.Background()
-
-	// 查询所有 active 的账户，然后过滤 antigravity 平台
-	allAccounts, err := r.accountRepo.ListActive(ctx)
-	if err != nil {
-		log.Printf("[AntigravityQuota] Failed to list accounts: %v", err)
-		return
-	}
-
-	// 过滤 antigravity 平台账户
-	var accounts []Account
-	for _, acc := range allAccounts {
-		if acc.Platform == PlatformAntigravity {
-			accounts = append(accounts, acc)
-		}
-	}
-
-	if len(accounts) == 0 {
-		return
-	}
-
-	refreshed, failed := 0, 0
-
-	for i := range accounts {
-		account := &accounts[i]
-
-		if err := r.refreshAccountQuota(ctx, account); err != nil {
-			log.Printf("[AntigravityQuota] Account %d (%s) failed: %v", account.ID, account.Name, err)
-			failed++
-		} else {
-			refreshed++
-		}
-	}
-
-	log.Printf("[AntigravityQuota] Cycle complete: total=%d, refreshed=%d, failed=%d",
-		len(accounts), refreshed, failed)
-}
-
-// refreshAccountQuota 刷新单个账户的配额
-func (r *AntigravityQuotaRefresher) refreshAccountQuota(ctx context.Context, account *Account) error {
-	accessToken := account.GetCredential("access_token")
-	projectID := account.GetCredential("project_id")
-
-	if accessToken == "" {
-		return nil // 没有 access_token，跳过
-	}
-
-	// token 过期则跳过，由 TokenRefreshService 负责刷新
-	if r.isTokenExpired(account) {
-		return nil
-	}
-
-	// 获取代理 URL
-	var proxyURL string
-	if account.ProxyID != nil {
-		proxy, err := r.proxyRepo.GetByID(ctx, *account.ProxyID)
-		if err == nil && proxy != nil {
-			proxyURL = proxy.URL()
-		}
-	}
-
-	client := antigravity.NewClient(proxyURL)
-
-	if account.Extra == nil {
-		account.Extra = make(map[string]any)
-	}
-
-	// 获取账户信息（tier、project_id 等）
-	loadResp, loadRaw, _ := client.LoadCodeAssist(ctx, accessToken)
-	if loadRaw != nil {
-		account.Extra["load_code_assist"] = loadRaw
-	}
-	if loadResp != nil {
-		// 尝试从 API 获取 project_id
-		if projectID == "" && loadResp.CloudAICompanionProject != "" {
-			projectID = loadResp.CloudAICompanionProject
-			account.Credentials["project_id"] = projectID
-		}
-	}
-
-	// 如果仍然没有 project_id，随机生成一个并保存
-	if projectID == "" {
-		projectID = antigravity.GenerateMockProjectID()
-		account.Credentials["project_id"] = projectID
-		log.Printf("[AntigravityQuotaRefresher] 为账户 %d 生成随机 project_id: %s", account.ID, projectID)
-	}
-
-	// 调用 API 获取配额
-	modelsResp, modelsRaw, err := client.FetchAvailableModels(ctx, accessToken, projectID)
-	if err != nil {
-		return r.accountRepo.Update(ctx, account) // 保存已有的 load_code_assist 信息
-	}
-
-	// 保存完整的配额响应
-	if modelsRaw != nil {
-		account.Extra["available_models"] = modelsRaw
-	}
-
-	// 解析配额数据为前端使用的格式
-	r.updateAccountQuota(account, modelsResp)
-
-	account.Extra["last_refresh"] = time.Now().Format(time.RFC3339)
-
-	// 保存到数据库
-	return r.accountRepo.Update(ctx, account)
-}
-
-// isTokenExpired 检查 token 是否过期
-func (r *AntigravityQuotaRefresher) isTokenExpired(account *Account) bool {
-	expiresAt := account.GetCredentialAsTime("expires_at")
-	if expiresAt == nil {
-		return false
-	}
-
-	// 提前 5 分钟认为过期
-	return time.Now().Add(5 * time.Minute).After(*expiresAt)
-}
-
-// updateAccountQuota 更新账户的配额信息（前端使用的格式）
-func (r *AntigravityQuotaRefresher) updateAccountQuota(account *Account, modelsResp *antigravity.FetchAvailableModelsResponse) {
-	quota := make(map[string]any)
-
-	for modelName, modelInfo := range modelsResp.Models {
-		if modelInfo.QuotaInfo == nil {
-			continue
-		}
-
-		// 转换 remainingFraction (0.0-1.0) 为百分比 (0-100)
-		remaining := int(modelInfo.QuotaInfo.RemainingFraction * 100)
-
-		quota[modelName] = map[string]any{
-			"remaining":  remaining,
-			"reset_time": modelInfo.QuotaInfo.ResetTime,
-		}
-	}
-
-	account.Extra["quota"] = quota
-}
diff --git a/backend/internal/service/quota_fetcher.go b/backend/internal/service/quota_fetcher.go
new file mode 100644
index 00000000..5c376d70
--- /dev/null
+++ b/backend/internal/service/quota_fetcher.go
@@ -0,0 +1,21 @@
+package service
+
+import (
+	"context"
+)
+
+// QuotaFetcher 额度获取接口，各平台实现此接口
+type QuotaFetcher interface {
+	// CanFetch 检查是否可以获取此账户的额度
+	CanFetch(account *Account) bool
+	// GetProxyURL 获取账户的代理 URL（如果没有代理则返回空字符串）
+	GetProxyURL(ctx context.Context, account *Account) (string, error)
+	// FetchQuota 获取账户额度信息
+	FetchQuota(ctx context.Context, account *Account, proxyURL string) (*QuotaResult, error)
+}
+
+// QuotaResult 额度获取结果
+type QuotaResult struct {
+	UsageInfo *UsageInfo     // 转换后的使用信息
+	Raw       map[string]any // 原始响应，可存入 account.Extra
+}