diff --git a/agent/plugin_hook_loader.py b/agent/plugin_hook_loader.py
index 7be815c..9ad8a10 100644
--- a/agent/plugin_hook_loader.py
+++ b/agent/plugin_hook_loader.py
@@ -165,27 +165,30 @@ async def _execute_command(skill_path: str, command: str, hook_type: str, config
     """
     try:
         # 设置环境变量，传递给子进程
+        # 注意：subprocess 要求所有 env 值必须是 str 类型，
+        # getattr 可能返回 None（属性存在但值为 None），需要确保转换为 str
         env = os.environ.copy()
-        env['ASSISTANT_ID'] = getattr(config, 'bot_id', '')
-        env['USER_IDENTIFIER'] = getattr(config, 'user_identifier', '')
-        env['TRACE_ID'] = getattr(config, 'trace_id', '')
-        env['SESSION_ID'] = getattr(config, 'session_id', '')
-        env['LANGUAGE'] = getattr(config, 'language', '')
+        env['ASSISTANT_ID'] = str(getattr(config, 'bot_id', '') or '')
+        env['USER_IDENTIFIER'] = str(getattr(config, 'user_identifier', '') or '')
+        env['TRACE_ID'] = str(getattr(config, 'trace_id', '') or '')
+        env['SESSION_ID'] = str(getattr(config, 'session_id', '') or '')
+        env['LANGUAGE'] = str(getattr(config, 'language', '') or '')
         env['HOOK_TYPE'] = hook_type
 
         # 合并 config 中的自定义 shell 环境变量
         shell_env = getattr(config, 'shell_env', None)
         if shell_env:
-            env.update(shell_env)
+            # 确保所有自定义环境变量值也是字符串
+            env.update({k: str(v) if v is not None else '' for k, v in shell_env.items()})
 
         # 对于 PreSave，传递 content
         if hook_type == 'PreSave':
-            env['CONTENT'] = kwargs.get('content', '')
-            env['ROLE'] = kwargs.get('role', '')
+            env['CONTENT'] = str(kwargs.get('content', '') or '')
+            env['ROLE'] = str(kwargs.get('role', '') or '')
 
         # 对于 PostAgent，传递 response
         if hook_type == 'PostAgent':
-            env['RESPONSE'] = kwargs.get('response', '')
+            env['RESPONSE'] = str(kwargs.get('response', '') or '')
             metadata = kwargs.get('metadata', {})
             env['METADATA'] = json.dumps(metadata) if metadata else ''
 
diff --git a/utils/settings.py b/utils/settings.py
index 915cc5a..16af267 100644
--- a/utils/settings.py
+++ b/utils/settings.py
@@ -57,7 +57,7 @@ CHECKPOINT_DB_URL = os.getenv("CHECKPOINT_DB_URL", "postgresql://moshui:@localho
 # 连接池大小
 # 同时可以持有的最大连接数
 CHECKPOINT_POOL_SIZE = int(os.getenv("CHECKPOINT_POOL_SIZE", "20"))
-MEM0_POOL_SIZE = int(os.getenv("MEM0_POOL_SIZE", "20"))
+MEM0_POOL_SIZE = int(os.getenv("MEM0_POOL_SIZE", "50"))
 
 # Checkpoint 自动清理配置
 # 是否启用自动清理旧 session