The index
The source of any page
Add.md to a page’s URL and you get its markdown source rather than the rendered page:
Using them
Give the index, not the pages. An assistant that hasllms.txt can fetch what it needs. One that has been pasted four pages will answer from those four and not know what it is missing.
Fetch the source, not the rendered page. The rendered page carries navigation, search and styling that add noise and no meaning.
Re-fetch rather than cache. These files are generated from the same pages you are reading, so they change when the documentation changes. An assistant working from a copy taken weeks ago will confidently describe a shape that has moved.