The toolschecker code currently lacks documentation on the Wikitech page.

The task at hand is to read through the code and describe what each endpoint of this small flask app does and how to respond when it isn't working. In many cases, it will help to refer to the Toolforge documentation for deeper context. These endpoints generate alerts, but without documentation, it can be hard for admins to know how to respond when the alert goes off.

The mostly empty document to fill out is here:
https://wikitech.wikimedia.org/wiki/Portal:Toolforge/Admin/Toolschecker