diff --git a/backend/internal/service/antigravity_gateway_service.go b/backend/internal/service/antigravity_gateway_service.go
index 3b847bcb..7fd8ef5d 100644
--- a/backend/internal/service/antigravity_gateway_service.go
+++ b/backend/internal/service/antigravity_gateway_service.go
@@ -1530,7 +1530,11 @@ func sleepAntigravityBackoffWithContext(ctx context.Context, attempt int) bool {
 
 func antigravityUseScopeRateLimit() bool {
 	v := strings.ToLower(strings.TrimSpace(os.Getenv(antigravityScopeRateLimitEnv)))
-	return v == "1" || v == "true" || v == "yes" || v == "on"
+	// 默认开启按配额域限流，只有明确设置为禁用值时才关闭
+	if v == "0" || v == "false" || v == "no" || v == "off" {
+		return false
+	}
+	return true
 }
 
 func (s *AntigravityGatewayService) handleUpstreamError(ctx context.Context, prefix string, account *Account, statusCode int, headers http.Header, body []byte, quotaScope AntigravityQuotaScope) {