What it means
A useful llms.txt file gives a reader a short introduction and a considered route into your material. For a software business, that might mean links to installation instructions, current API documentation, and account limits. The value comes from helping a reader locate accurate information, rather than collecting every page in one place.
The published proposal uses Markdown and remains a proposal. Its August 2026 revision allows files within sections of a site and describes ways to link to them. Some publishers also provide llms-full.txt as expanded text. That companion file is a publishing convention, not something every website must add.
These files do not replace readable public pages, ordinary navigation, or your published crawler policy. A business can maintain them when they support a real documentation workflow. Their presence alone does not demonstrate that a particular assistant discovered them or used their contents.
Hypothetical example: a guide to current documentation
A fictional booking platform publishes a brief introduction followed by links to its setup guide, cancellation rules, and API reference. It keeps those links current when documentation moves. This may provide a useful starting point for a tool that chooses to read it; it is not a measured citation improvement.
How BLURSOR measures it
In the report: llms.txt · llms-full.txt
BLURSOR requests the root locations /llms.txt and /llms-full.txt separately. It checks the returned text, response classification, and capture limits. It does not search every subdirectory or follow all discovery links described by the proposal.
The checker expects a leading Markdown H1 for both files and an H2 section for llms.txt. The proposal requires only the H1, so this checker result is an expected-shape test, not a complete judgment of proposal compliance. A capped capture also limits what can be concluded about the full document.
What to do next
- Publish a concise guide if customers or documentation tools have a useful reason to consult it.
- Assign an owner to update its descriptions and links when products or policies change.
- Review the resolved response and capture notes before treating a format warning as a whole-file problem.
What it cannot tell you
- A missing optional file is not evidence that the page is inaccessible or cannot be cited.
- The checker does not verify the factual accuracy of the document or whether any outside service consumes it.
Sources and further reading
The definitions below describe the underlying concepts. The measurement section describes BLURSOR’s own checks.