llms.txt Syntax Check
llms.txt syntax errors are invisible to human readers but break AI crawler parsers. A list item like "- https://example.com/page" is valid Markdown but violates the llms.txt spec — links must use the [text](url) Markdown format so crawlers can extract a human-readable title alongside the URL.
This linter catches the syntax issues that matter for LLM compatibility: bare URLs in lists, H1 placement errors (H1 must be first), blockquotes in the wrong position, plain text inside sections, H3+ headings (not part of the spec), and malformed URL patterns.
Each flagged line includes a corrected example so you can fix and re-validate in seconds. The check runs entirely in your browser — no backend, no API key, no file upload.
How to use
- Paste your llms.txt content into the input area on the main tool page, or drag and drop your file.
- Click Validate — errors and warnings appear instantly with line numbers and fix suggestions.
- Fix the flagged issues and re-validate until the green Valid llms.txt badge appears.