feat: enhance sandbox api

src/langbot/pkg/box/service.py

@@ -208,6 +208,7 @@ class BoxService:
         return {
             'session_id': spec.session_id,
             'workdir': spec.workdir,
+            'mount_path': spec.mount_path,
             'timeout_sec': spec.timeout_sec,
             'network': spec.network.value,
             'image': spec.image,

src/langbot/pkg/provider/tools/loaders/native.py

@@ -55,7 +55,18 @@ class NativeToolLoader(loader.ToolLoader):
                     },
                     'workdir': {
                         'type': 'string',
-                        'description': 'Absolute working directory path inside the sandbox. Defaults to /workspace.',
+                        'description': (
+                            'Absolute working directory path inside the sandbox. '
+                            'Defaults to mount_path, or /workspace when mount_path is omitted.'
+                        ),
+                        'default': '/workspace',
+                    },
+                    'mount_path': {
+                        'type': 'string',
+                        'description': (
+                            'Absolute sandbox path where host_path is mounted. '
+                            'Defaults to /workspace. When omitted, workdir defaults to the same path.'
+                        ),
                         'default': '/workspace',
                     },
                     'timeout_sec': {