diff --git a/apps/ai-game-creator-shell/src-tauri/src/agent/design_runtime.rs b/apps/ai-game-creator-shell/src-tauri/src/agent/design_runtime.rs
index fbb42a22a..9e907c2c0 100644
--- a/apps/ai-game-creator-shell/src-tauri/src/agent/design_runtime.rs
+++ b/apps/ai-game-creator-shell/src-tauri/src/agent/design_runtime.rs
@@ -1696,10 +1696,40 @@ mod tests {
             .clone()
     }
 
+    // 进程级 env 在同一 binary 的并行用例间共享：持锁串行化修改，drop 时恢复原值，
+    // 避免 debug 开关泄漏给并发用例。锁中毒时取内部值继续，不让上游失败放大。
+    static DESIGN_DEBUG_ENV_LOCK: std::sync::Mutex<()> = std::sync::Mutex::new(());
+
+    struct DesignDebugEnvGuard {
+        previous: Option<String>,
+        _lock: std::sync::MutexGuard<'static, ()>,
+    }
+
+    impl Drop for DesignDebugEnvGuard {
+        fn drop(&mut self) {
+            match &self.previous {
+                Some(value) => std::env::set_var("GENARRATIVE_AGC_DESIGN_DEBUG", value),
+                None => std::env::remove_var("GENARRATIVE_AGC_DESIGN_DEBUG"),
+            }
+        }
+    }
+
+    fn enable_design_debug_for_test() -> DesignDebugEnvGuard {
+        let lock = DESIGN_DEBUG_ENV_LOCK
+            .lock()
+            .unwrap_or_else(|poisoned| poisoned.into_inner());
+        let previous = std::env::var("GENARRATIVE_AGC_DESIGN_DEBUG").ok();
+        std::env::set_var("GENARRATIVE_AGC_DESIGN_DEBUG", "1");
+        DesignDebugEnvGuard {
+            previous,
+            _lock: lock,
+        }
+    }
+
     #[tokio::test(flavor = "current_thread")]
     async fn design_tool_panic_becomes_visible_retryable_error() {
         let (_temp, root, resources) = init_design_project();
-        std::env::set_var("GENARRATIVE_AGC_DESIGN_DEBUG", "1");
+        let _debug_env = enable_design_debug_for_test();
         let panic_call = platform_llm::LlmToolCall {
             id: "call-panic".into(),
             name: "design_test__panic".into(),