diff --git a/auto-setup.ps1 b/auto-setup.ps1
index 9adfa4b..232d118 100644
--- a/auto-setup.ps1
+++ b/auto-setup.ps1
@@ -952,9 +952,25 @@ Log-Phase 4 "凭证解密"
 
 $secretsDecrypted = $false
 
-# 先查缓存
-if (Get-CachedSecrets) {
-    Log-OK "从本日缓存加载凭证 (免密)"
+# 优先级 1: User 级环境变量已有 (上次安装已永久写入)
+$existingKey = [System.Environment]::GetEnvironmentVariable("ANTHROPIC_API_KEY", "User")
+$existingUrl = [System.Environment]::GetEnvironmentVariable("ANTHROPIC_BASE_URL", "User")
+if ($existingKey) {
+    # 注入到当前 Process (User 环境变量新终端才生效, 当前进程需手动加载)
+    $env:ANTHROPIC_API_KEY = $existingKey
+    if ($existingUrl) { $env:ANTHROPIC_BASE_URL = $existingUrl }
+    # 加载其他 Key (如果有)
+    foreach ($k in $CacheAllowedKeys) {
+        $v = [System.Environment]::GetEnvironmentVariable($k, "User")
+        if ($v) { [System.Environment]::SetEnvironmentVariable($k, $v, "Process") }
+    }
+    Log-OK "从系统环境变量加载凭证 (已有安装记录, 免输授权码)"
+    $secretsDecrypted = $true
+}
+
+# 优先级 2: Registry DPAPI 缓存
+if (-not $secretsDecrypted -and (Get-CachedSecrets)) {
+    Log-OK "从 Registry 缓存加载凭证"
     $secretsDecrypted = $true
 }
 # 再解密 (缓存命中则跳过)