diff --git a/openhands/runtime/impl/remote/remote_runtime.py b/openhands/runtime/impl/remote/remote_runtime.py
index f33acedbf4ad..c54bb69dbdde 100644
--- a/openhands/runtime/impl/remote/remote_runtime.py
+++ b/openhands/runtime/impl/remote/remote_runtime.py
@@ -215,7 +215,7 @@ def _start_runtime(self):
         environment = {
             'DEBUG': 'true'
             if self.config.debug or os.environ.get('DEBUG', 'false').lower() == 'true'
-            else {},
+            else '',
         }
         environment.update(self.config.sandbox.runtime_startup_env_vars)
         start_request = {