Answer-first writing puts the conclusion where readers, search snippets, and AI systems all look: at the top. A section titled "Rate limits" opens with the actual limit, then explains tiers and exceptions.
The style exists because most readers do not read pages, they scan for one fact. It has become more important with AI: retrieval systems and answer engines quote individual passages, and a passage that opens with its answer survives being quoted alone.
In practice it means three habits: lead each page and section with the direct answer, put context after the answer instead of before it, and make headings match the questions users actually ask.