diff --git a/backend/internal/pkg/antigravity/client.go b/backend/internal/pkg/antigravity/client.go
index ac32fae5..f1aa744a 100644
--- a/backend/internal/pkg/antigravity/client.go
+++ b/backend/internal/pkg/antigravity/client.go
@@ -33,7 +33,7 @@ func NewAPIRequestWithURL(ctx context.Context, baseURL, action, accessToken stri
 	// 基础 Headers（与 Antigravity-Manager 保持一致，只设置这 3 个）
 	req.Header.Set("Content-Type", "application/json")
 	req.Header.Set("Authorization", "Bearer "+accessToken)
-	req.Header.Set("User-Agent", UserAgent)
+	req.Header.Set("User-Agent", GetUserAgent())
 
 	return req, nil
 }
@@ -333,7 +333,7 @@ func (c *Client) LoadCodeAssist(ctx context.Context, accessToken string) (*LoadC
 		}
 		req.Header.Set("Authorization", "Bearer "+accessToken)
 		req.Header.Set("Content-Type", "application/json")
-		req.Header.Set("User-Agent", UserAgent)
+		req.Header.Set("User-Agent", GetUserAgent())
 
 		resp, err := c.httpClient.Do(req)
 		if err != nil {
@@ -412,7 +412,7 @@ func (c *Client) OnboardUser(ctx context.Context, accessToken, tierID string) (s
 			}
 			req.Header.Set("Authorization", "Bearer "+accessToken)
 			req.Header.Set("Content-Type", "application/json")
-			req.Header.Set("User-Agent", UserAgent)
+			req.Header.Set("User-Agent", GetUserAgent())
 
 			resp, err := c.httpClient.Do(req)
 			if err != nil {
@@ -532,7 +532,7 @@ func (c *Client) FetchAvailableModels(ctx context.Context, accessToken, projectI
 		}
 		req.Header.Set("Authorization", "Bearer "+accessToken)
 		req.Header.Set("Content-Type", "application/json")
-		req.Header.Set("User-Agent", UserAgent)
+		req.Header.Set("User-Agent", GetUserAgent())
 
 		resp, err := c.httpClient.Do(req)
 		if err != nil {
diff --git a/backend/internal/pkg/antigravity/oauth.go b/backend/internal/pkg/antigravity/oauth.go
index d1712c98..89b1bcde 100644
--- a/backend/internal/pkg/antigravity/oauth.go
+++ b/backend/internal/pkg/antigravity/oauth.go
@@ -7,6 +7,7 @@ import (
 	"encoding/hex"
 	"fmt"
 	"net/url"
+	"os"
 	"strings"
 	"sync"
 	"time"
@@ -32,9 +33,6 @@ const (
 		"https://www.googleapis.com/auth/cclog " +
 		"https://www.googleapis.com/auth/experimentsandconfigs"
 
-	// User-Agent（与 Antigravity-Manager 保持一致）
-	UserAgent = "antigravity/1.15.8 windows/amd64"
-
 	// Session 过期时间
 	SessionTTL = 30 * time.Minute
 
@@ -46,6 +44,21 @@ const (
 	antigravityDailyBaseURL = "https://daily-cloudcode-pa.sandbox.googleapis.com"
 )
 
+// defaultUserAgentVersion 可通过环境变量 ANTIGRAVITY_USER_AGENT_VERSION 配置，默认 1.84.2
+var defaultUserAgentVersion = "1.84.2"
+
+func init() {
+	// 从环境变量读取版本号，未设置则使用默认值
+	if version := os.Getenv("ANTIGRAVITY_USER_AGENT_VERSION"); version != "" {
+		defaultUserAgentVersion = version
+	}
+}
+
+// GetUserAgent 返回当前配置的 User-Agent
+func GetUserAgent() string {
+	return fmt.Sprintf("antigravity/%s windows/amd64", defaultUserAgentVersion)
+}
+
 // BaseURLs 定义 Antigravity API 端点（与 Antigravity-Manager 保持一致）
 var BaseURLs = []string{
 	antigravityProdBaseURL,  // prod (优先)