What's on this page

• llms.txt
  • HTTP headers
  • Exclude content
• Markdown pages
  • Prevent indexing
• Templates

Content for LLMs

Language models read Markdown more easily than HTML. Cecil provides two output formats for them:

• llms: a llms.txt file, an index of the site;
• markdown: a Markdown version of each page.

Both are disabled by default.

llms.txt

Since version 8.114.0, the llms format renders the homepage as a llms.txt file at the root of the site. It contains:

• the site title and description;
• the links of the main menu (external URLs are ignored);
• the top-level sections and their pages (sub-sections are nested), with their title and description.

To enable it, add the format to the homepage:

output:
  pagetypeformats:
    homepage:
      llms: true

With the metatags template, the HTML homepage references the file with a <link rel="describedby" type="text/markdown"> tag.

HTTP headers

You can also advertise the file to crawlers and agents with HTTP headers, using the server.headers option:

server:
  headers:
    - path: /*
      headers:
        # LLMs
        - key: Link
          value: '</llms.txt>; rel="llms-txt"'
        - key: X-Llms-Txt
          value: /llms.txt

These headers are only applied by the local preview server. To deploy them, use the Headers component theme: it generates a _headers file (supported by Netlify, statichost and Cloudflare Pages) including the headers defined in server.headers.

Exclude content

To exclude a page or a section (and its pages) from llms.txt, set llms: false in its front matter:

---
title: "Legal notice"
llms: false
---

Unpublished and excluded sections are not listed.

Markdown pages

The markdown format renders a page as a Markdown file, next to its HTML version (e.g.: blog/post-1.md for blog/post-1/index.html). The file contains the title and the body of the page; a section lists its pages.

To render all pages and sections in Markdown:

output:
  pagetypeformats:
    page:
      markdown: true
    section:
      markdown: true

Or for a single page, with the output variable:

---
output: [html, markdown]
---

With the metatags template, the HTML page references its Markdown version with a <link rel="alternate" type="text/markdown"> tag. The links of llms.txt point to the Markdown version of the pages when it exists.

Prevent indexing

To prevent search engines from indexing the Markdown pages (duplicate content of the HTML pages), add a X-Robots-Tag HTTP header with the server.headers option:

server:
  headers:
    # Markdown outputs
    - path: "/*.md"
      headers:
        - key: X-Robots-Tag
          value: noindex

As for the llms.txt headers, use the Headers component theme to deploy it.

Templates

To customize these outputs, override the default templates in your layouts directory (see lookup rules):

• home.llms.twig: the llms.txt file;
• page.markdown.twig, list.markdown.twig and home.markdown.twig: the Markdown pages.