Updated August 11, 2026
llms.txt structure reference
llms.txt is a Markdown file that points AI tools to a site's most useful pages. This sheet lists the parts of the file, which are required, and the exact Markdown each uses.
File parts
The file is read top to bottom. Only the H1 name is strictly required.
| Section | Required | Purpose |
|---|---|---|
# Name | Yes | H1 with the site or project name. The only required line. |
> Summary | No | A blockquote with a short description of the site and who it is for. |
Details | No | Free Markdown paragraphs after the summary for extra context. |
## Section | No | H2 headings group related links, e.g. Primary resources or Docs. |
## Optional | No | A section tools may skip when they need a shorter context window. |
Link list format
| Item | Meaning |
|---|---|
- [Name](url) | A link item under a section. Use absolute URLs. |
- [Name](url): note | A link with an optional description after the colon. |
Example
A complete llms.txt with the common sections.
# Example
> Fast, privacy-first tools for developers and creators.
## Primary resources
- [Docs](https://example.com/docs): Guides and getting started.
- [API](https://example.com/api): Endpoint reference.
- [Sitemap](https://example.com/sitemap.xml)
## Categories
- [Images](https://example.com/image): Image tools.
- [PDF](https://example.com/pdf): PDF tools.
## Optional
- [Full catalog](https://example.com/llms-full.txt)Location and formatServe the file at
https://example.com/llms.txt as plain text or Markdown. Use absolute URLs for links so any tool can resolve them. A companion llms-full.txt can inline the full content in one file.Guidance, not access controlllms.txt describes and recommends; it does not restrict. Use robots.txt for crawler access preferences and authentication for anything private. It is also a community proposal, so support varies by tool.
References
Questions
Which part of llms.txt is required?
Only the H1 name line (`# Name`). The summary blockquote, sections, and link lists are all optional, though a summary and at least one link make the file useful.
What is the Optional section for?
It marks links a tool can skip when it needs a smaller context. Put nice-to-have references there and keep essential links in the main sections.
Should URLs be absolute?
Yes. Use full https:// URLs so any AI tool can resolve them without knowing the site's base URL.