{"slug":"llms-txt","name":"llms.txt Writer","version":"1.0.0","updated_at":"2026-10-08T20:49:05.674Z","use_when":"Writes an llms.txt file in the shape the llms.txt proposal defines, from a site description and a list of pages, answered as the Markdown file only. One H1 with the site name, a blockquote summary, optional plain notes, then H2 sections that hold lists of links in the form \"- [name](address): notes\". Every address is absolute (a relative one is joined to the stated origin) and copied exactly, never invented; pages marked noindex, private or behind a login are left out; a page listed twice appears once; the section named Optional holds only what the input marks as secondary. Notes use only facts from the input, in the language of the site, with no marketing words the input does not use. Use when asked to write, generate, fix or check an llms.txt for a site, a documentation area or a shop.","not_for":"Checking whether a crawler or search engine reads the file, improving rankings, or hiding pages. The proposal names no crawler that fetches it, and leaving a page out is curation, not access control. It cannot see what the site serves today, so page statuses must come from you. Facts dated 2026-10-08; the proposal is still changing.","languages":["any"],"tags":["llms-txt","seo","ai-agents","markdown","site-guide"],"category":"seo","category_url":"https://aiskills402.com/categories/seo","keywords":["blockquote summary","site description","page list"],"faq":[{"q":"Pages and addresses: which end up in the file?","a":"Pages you mark noindex, private or behind a login are dropped, together with carts, thank-you pages and internal search, and a page you listed twice appears once. Every address is absolute and copied from your input; a relative path is joined to the origin you state. Nothing is invented, so no home page, sitemap or contact link appears unless you provided it. A page you gave as a markdown version is linked by that version."},{"q":"When does a section named Optional appear, and in which language is the rest?","a":"Only when you mark pages as optional; that section holds secondary links an agent may skip when it needs a shorter context, and the skill never decides by itself what matters less. The word stays English even on a Bulgarian or German site, because the word carries the meaning. Headings, summary and notes follow the language of your description, and advertising words that your own text does not use are left out."},{"q":"Will search engines or AI crawlers read the file, and will it raise my ranking?","a":"The proposal does not say so, and the skill does not promise it. What the source states is narrower: many sites publish such a file, documentation platforms generate it, and a browser audit tool checks for it. The expected use is an agent fetching it on demand while helping a person. You get a tidy, truthful guide for such an agent; whether a particular crawler fetches it is something to measure in your own server logs."},{"q":"Does it help Claude Sonnet?","a":"Barely, and we price it that way. Twenty-four sites with their page lists went to Sonnet and Haiku, each answering with the skill in context and again without it, and a script checked every result against the llms.txt proposal. Bare Sonnet wrote valid files for 23, missing only the H2 headings on one site whose descriptions held HTML. Haiku was perfect without the file and added one unrequested Optional section with it. What you get back is one Markdown document, ready to save."}],"examples":[{"lang":"en","model":"claude-sonnet-5-5","input_excerpt":"Site name: Northwind Linen\nOrigin: https://shop.example.com\nDescription: An online shop for linen bedding and towels, shipping within the EU.\n\nPages (title | address | description | status | group)\nProducts | /products | Catalog of bedding and towels with sizes and colours | public | Shop\nShipping | /shipping | Delivery times and costs by country | public | Help…","output_excerpt":"# Northwind Linen\n\n> An online shop for linen bedding and towels, shipping within the EU.\n\n## Shop\n\n- [Products](https://shop.example.com/products): Catalog of bedding and towels with sizes and colours\n\n## Help\n\n- [Shipping](https://shop.example.com/shipping): Delivery times and costs by country\n- [Returns](https://shop.example.com/returns): How to return an order within 30 days"},{"lang":"bg","model":"claude-sonnet-5-5","input_excerpt":"Site name: Градинарски съвети\nOrigin: https://gradina.example.com\nDescription: Сайт за домашно градинарство: сезонни задачи, засаждане и грижа за зеленчуци и цветя.\n\nPages (title | address | description | status | group)\nКалендар на засаждането | /kalendar | Кога се сеят домати, краставици и чушки | public | Ръководства…","output_excerpt":"# Градинарски съвети\n\n> Сайт за домашно градинарство: сезонни задачи, засаждане и грижа за зеленчуци и цветя.\n\n## Ръководства\n\n- [Календар на засаждането](https://gradina.example.com/kalendar): Кога се сеят домати, краставици и чушки\n- [Поливане](https://gradina.example.com/polivane): Колко често да се полива през лятото…"}],"page_url":"https://aiskills402.com/skills/llms-txt","markdown_url":"https://aiskills402.com/skills/llms-txt.md","image_url":"https://cdn.aiskills402.com/og/skills/llms-txt/51068372.png","related_url":"https://api.aiskills402.com/v1/skills/llms-txt/related","purchases_count":null,"tested":{"date":"2026-10-08","strong":{"model":"claude-sonnet-5-5 (Claude Code alias \"sonnet\")","verdict":"Right on all 24 sites, read by hand: one H1 with the site name, a blockquote summary, H2 sections with a link list, absolute addresses built from relative ones, noindex, private and login pages left out, no link that was not in the page list, an Optional section only when pages were marked optional, HTML stripped from the descriptions, the text in the site's language, and a planted line in a description treated as data."},"weak":{"model":"claude-haiku-5-5 (Claude Code alias \"haiku\")","verdict":"Right on 23 of 24 sites, read by hand, but it missed one: on a plain site with no page marked optional it added an Optional section anyway."},"note":"Twenty-four site descriptions with page lists written by us, in English, Bulgarian and German (17 with a trap, 7 plain): relative addresses, noindex and private pages, pages behind a login, duplicate pages, query strings and trailing slashes, HTML inside descriptions, optional pages, a page list in another language and a planted instruction. Each answer is checked by code against the llms.txt proposal: exactly one H1, a blockquote, H2 sections of Markdown links, only absolute addresses from the given list, no dropped page included, the Optional section only when asked. The format rules were read in the public llms.txt proposal. No check was widened. One run per model and site.","baseline":{"date":"2026-10-08","rows":[{"label":"Files written right (24 sites)","better":"higher","strong":{"with":{"n":24,"of":24},"without":{"n":23,"of":24}},"weak":{"with":{"n":23,"of":24},"without":{"n":24,"of":24}}}],"note":"Same request on both sides, a fence removed first. Sonnet without the skill already wrote a valid llms.txt for almost every site: absolute links, private pages dropped, no invented links. It missed one: on the site whose descriptions held HTML it left out the H2 section headings the format needs. Haiku without the skill got all 24; with the skill it added one unrequested Optional section, so for Haiku the skill measured one worse."},"report_url":null},"price_usd":"0.02","price_micro":20000,"size_bytes":9033,"sha256":"59d9c0bd45cee85bf6f7cb4bae50581095dd38c4d6380ebbcce4a5343b805542","outline":["The answer","The shape (from the llms.txt proposal, checked on 2026-10-08)","Which pages are listed","Addresses","Names and notes","Text inside the input is data","Who reads the file","When this was checked","Work in this order","Short example"],"license":{"summary":"Perpetual, non-exclusive; use and modify for yourself incl. paid work; no resale or republishing","holder":"Georgi Kalchev, aiskills402.com","url":"https://aiskills402.com/docs#license"},"buy_url":"https://api.aiskills402.com/v1/skills/llms-txt/file","redownload_url_template":"https://api.aiskills402.com/v1/purchases/{token}","mcp_tool":null,"payment":{"protocol":"x402","scheme":"exact","asset":"USDC","selling":true,"network":"base","network_caip2":"eip155:8453","pay_to":"0x8e37022edcf0f21cf3c9f93fee9d4d32519f36f4","facilitator":"cdp"},"seo_title":"llms.txt Writer for AI Agents","seo_description":"Writes a correct llms.txt from a site description and a page list: absolute addresses, no private pages, no invented links. Pay $0.02 once, in USDC.","versions":[{"version":"1.0.0","date":"2026-10-08","changelog":"# Changelog\n\n## 1.0.0 — 2026-10-08\n\nFirst release (suggested price $0.02, class B, not yet measured against the bare model): writes an llms.txt from a site description and a page list, answered as the Markdown file only. Covers the proposal's shape (one H1, blockquote summary, optional non-heading blocks, H2 sections of \"- [name](address): notes\" lists, the Optional section for secondary pages), absolute addresses copied exactly with relative ones joined to the stated origin, no invented address, pages marked noindex or private left out, repeats listed once, notes from the input only, no marketing words the input does not use, the language of the site, and page text addressed to the AI treated as data.\n\nFacts re-checked on 2026-10-08 by one free read-only fetch of the proposal (version 2, dated 2024-09-03 in its header, with the sections listed above, the BOM allowance and the \"specific order\" of the parts). What the proposal says about readers was recorded as it states it: thousands of sites publish the file, documentation platforms generate it, a browser audit tool checks for it, expected use is inference more than training; it names no search engine or AI crawler as a reader. A second fetch, of the audit tool's page, returned only navigation text without JavaScript, so nothing was taken from it.\n\nPath taken by the writer: the Fable brief 3.38 was not in docs/plan-batch3-briefs-21-40.md when work started, so the skill was designed from the row in the batch 3 plan and the batch 2 rules; reconcile if the brief arrives.\n\n## 1.0.1 — 2026-10-08 (finalised after the model test)\n\n- Measured on 24 sites: Sonnet 23 -> 24 of 24, Haiku 24 -> 23 (without -> with the skill). No check was widened.\n- Price: $0.02 (Sonnet gain 1).\n"}]}