llms.txt validator

Use this llms.txt validator to inspect a pasted or published file. Review Markdown structure, llms-full.txt and optional link checks before editing it.

An llms.txt validator checks a file against the proposed format at llmstxt.org: one H1 title, an optional summary and H2 sections containing Markdown links. Paste text or request a site check to see errors and warnings by line. Link checks can reveal missing pages, but a valid file does not guarantee assistant use or citations.

Choose the input

Up to 100,000 bytes. Local format checks do not send the text to the API.

Relative links are allowed. Add their site if you want to check their responses.

What this format can establish

Checked against the llmstxt.org proposal v2, updated 10 August 2026.

The proposal describes a file that tools can explicitly load for context. It does not promise that consumer assistants automatically request it, use it for training or cite your site. OpenAI and Anthropic document crawler controls separately. Publishing a valid llms.txt does not grant access blocked by robots.txt or authentication.

The proposal lists the VS Code PagePilot extension as an integration that loads external context, and an MCP server for fetching llms.txt files. It links files published for OpenAI, Anthropic and Gemini developer docs. These examples do not establish automatic use by every consumer assistant.

Read the format proposal · OpenAI crawler documentation · Anthropic crawler documentation

How this tool works

Choose text or a site
Pasted text is checked locally unless you request link checks. Enter a site, directory or exact llms.txt URL. Site mode requests llms.txt and llms-full.txt in that directory. Relative destinations are valid; supply their directory or file URL to resolve them for network checks.
Fix the reported lines
The format proposal requires a title. The blockquote summary, introduction and sections are optional. Inside a section, use Markdown link lists with optional notes. An Optional section identifies material that can be skipped when a shorter context is needed.
Treat live checks as a snapshot
Every unique link is listed. Each batch checks up to 50 links with four requests at once, a 20-second budget and robots rules. Continue to the next batch to check remaining links. HEAD has a bounded GET fallback. Restrictions, timeouts and private destinations remain explicit.

Related tools

  • llms.txt generator and validator

    Use this llms.txt generator to build an editable file from a website, XML sitemap or pasted page list. Organize sections, review descriptions, then copy or download the Markdown.

  • Broken link checker

    Use this broken link checker on a page or crawl up to 50 source pages. Find failed links and resources, then export their source pages to guide repairs.

  • Can AI read my website

    Can AI read my website? Compare raw HTML text, headings, links and structured data across crawler requests. Check access rules and spot JavaScript shells.

Before you start

There is no universal guarantee. The proposal supports tools that explicitly load these files. A publisher offering llms.txt does not establish that every consumer assistant reads it during search or uses it for training. Check the documentation of the specific assistant or integration.

No. It is a common companion containing expanded text, not a required part of the llms.txt format. This tool checks whether the companion returns a readable response in site mode and reports HTML fallbacks separately.

Yes. Relative links are allowed in the proposal. The local format check accepts them. For live link checks, enter the site address they belong to; without it, relative destinations remain unresolved and are not requested.

Check what assistants can find

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