Safely get tool default version instead of using direct @ access.
See also
Other accessor functions:
sn_get_installed_versions()
,
sn_get_tool()
,
sn_get_tool_commands()
,
sn_get_tool_name()
,
sn_get_tool_versions()
,
sn_get_toolbox_tools()
,
sn_get_toolcall_outputs()
,
sn_get_toolcall_runtime()
,
sn_get_toolcall_status()
,
sn_is_tool_installed()
,
sn_is_toolcall_success()