If others are not able to see the tools home directory, there is technically no way (besides using sudo) to know the tools source code / data / setup, unless the source code is published //and// the exact steps to duplicate the environment is publicly documented elsewhere, others will not be able to debug what is wrong with a tool if they have issues with it. I suggest that a documentation page like the [[https://wikitech.wikimedia.org/wiki/Help:Tool_Labs/FAQ#What_about_file_permissions.3F_Who_can_see_my_code.3F|FAQ]] could contain something like:
Do not set your tool home directory permissions so that others cannot read it, without documenting the full setup, because:
* it can be very difficult to ask for all the information required for debugging if you run into issues.
* no easy way to [[https://wikitech.wikimedia.org/wiki/Help:Tool_Labs/Right_to_fork_policy#What_the_right_to_fork_means_for_tool_maintainers|fork]] your tool.
* no transparency / openness; generally against labs ideology.
Unless a tool labs very good reasons to prevent reading every single file/directory in the tool home directory altogether (which I can't think of any), tools may hide individual files/directories in case of secret data.
See T164191#3228024 for one case where a tool chmod his tool dir 770