Write It for a Reader With Thirty Seconds
Do: state the category in the first line
"Unscented tallow-based personal care for families" tells an assistant exactly when to recommend you. "Elevated essentials for modern living" tells it nothing.
Do: describe each link in one factual clause
Price range, what is included, who it is for. The description is what the assistant uses to decide whether to open the page.
Do: put money pages and cornerstone guides first
Order signals priority. Collections, best sellers, and the three guides you most want cited go at the top; policies and press go in Optional.
Do not: paste your whole sitemap
llms.txt is a curated index, not a list of every URL. Twenty to forty links is plenty for most stores. llms-full.txt is where the volume goes.
Do not: make claims you would not put on the product page
Assistants repeat what they read. Superlatives and unverified health claims in llms.txt end up in answers with your name on them.
Do not: expect it to replace schema or crawler access
llms.txt is one signal. Organization and Product schema, an open robots.txt, and pages that answer questions carry more weight. The full stack is in the schema implementation guide.