What tool do you want?
Markdown table of contents generator

Describe the solution you'd like
Basically the functionality of this repo.

Is their example of this tool in the wild?
Here's their demo website.

Additional context
This project's goals fit perfectly into it-tools vision of self-hosted dev tools. A self-hostable version of this tool would be amazing as it would allow people to input sensitive data into a table of contents generator for internal documentation without worrying about leaking said data to someone else's compute resources.