Free tool · llms.txt
Write an llms.txt, or check the one you have.
This llms.txt generator writes the file from your sitemap or from a form, and the checker reads the one already on your site against the llmstxt.org proposal, which asks for one H1 naming the site, a blockquote summary, then sections of links. It runs in your browser with the same code Heddle uses to build and check llms.txt on the sites it runs, so the two always agree.
# Your site
Checked as you type
- Warningno blockquote summary under the H1; it is the line an assistant quotes to say what the site is
- Warningno H2 sections of links, so the file names the site and points nowhere
- Name
- Your site
- Summary
- none
- Sections
- none
- Links
- 0
How the tool decides
The checker follows the proposal at llmstxt.org line by line. The file opens with one H1 naming the site, the only part the proposal requires. A blockquote summary follows, then H2 sections, each a list of links written as - [name](url) with optional notes. A second H1, text before the H1 and list items that aren't links are reported, and so are relative links, because an assistant reads the file on its own.
What the checker looks for
Errors are what the proposal rules out, such as no H1, a second H1, or anything before the H1. Warnings follow the proposal but read badly to an assistant, such as a missing summary, a section with no links, a list item that isn't a link, or a relative link. Notes are harmless and worth knowing, like the same URL listed twice.
The checker fetches only /llms.txt from the site you name. It does not crawl your pages or check that each link resolves.
Where llms.txt helps
Google says its Search ignores llms.txt, so the file won't move a Google ranking. Other assistants and browser agents do read it, and it takes an hour to write, so it's a cheap bet rather than a ranking tactic. Our page on what llms.txt is has the sources.
If you change your site often, a hand-written file goes stale. Heddle writes it from the built pages on every deploy, together with a Markdown copy of each page, and its agent-ready gate fails the build when a page is missing from it.
Sources
Each was read on October 11, 2026.
Questions
Where does llms.txt go?
At the root of your domain, so it loads at https://yoursite.com/llms.txt, served as plain text. Most hosts serve a file from the public or static folder at that address.
Does anything I type get stored?
No. The generator and the checker run in your browser. To check a live file, our server fetches that one file from the address you give and passes it back; it keeps nothing and logs nothing about the site.
Should I link every page?
Link the pages an assistant needs to describe you correctly, such as what you sell, prices, documentation and contact. Put the rest under a section called Optional, which the proposal says an assistant can skip when it is short of room.
Work with us
Have the agents keep it true.
A file you write once goes stale the next time the site changes. Heddle writes llms.txt, robots.txt and the markup on every deploy, and its gates fail the build when one of them is wrong. Tell us about your site and we'll show you what they would catch.
On the call, for your site
- The searches your buyers makeMeasured, with how many people make each one
- Where you show up, and where you don'tOn Google and in ChatGPT's answers
- The agents' first monthThe pages, fixes and links they would start with