---
title: "/llms.txt doesn't follow the llms.txt format (geo/llms-txt-invalid)"
description: "geo/llms-txt-invalid: The spec requires an H1 as the first line, then an optional > summary, then ## sections of - [name](url): notes links."
canonical: https://void-design.vercel.app/rules/geo/llms-txt-invalid
lastModified: 2026-09-16
---

# /llms.txt doesn't follow the llms.txt format

`geo/llms-txt-invalid` · severity **warn** · category AI search · detected by `void geo` and `void audit`

## Why it matters

The spec requires an H1 as the first line, then an optional > summary, then ## sections of - [name](url): notes links. Lighthouse checks for the H1, a link and a length of at least 50.

## How to fix it

Restructure the file per llmstxt.org, serve it as text/markdown, and keep it curated (not a sitemap dump).

## References

- https://llmstxt.org/
- https://developer.chrome.com/docs/lighthouse/agentic-browsing/llms-txt

## More ai search rules

`void geo` reports 41 rules in this category. Generative-engine optimisation: whether AI crawlers that don't run JavaScript see the same content, valid and visible JSON-LD, an explicit AI robots policy, llms.txt, Markdown mirrors and answer-first writing.

- `markdown-negotiation-vary` Accept: text/markdown negotiation without Vary: Accept — [geo/markdown-negotiation-vary](https://void-design.vercel.app/rules/geo/markdown-negotiation-vary)
- `markdown-negotiation` No Markdown response for Accept: text/markdown — [geo/markdown-negotiation](https://void-design.vercel.app/rules/geo/markdown-negotiation)
- `llms-txt-missing` No /llms.txt — [geo/llms-txt-missing](https://void-design.vercel.app/rules/geo/llms-txt-missing)
- `llms-txt-error` /llms.txt returns a server error — [geo/llms-txt-error](https://void-design.vercel.app/rules/geo/llms-txt-error)
- `llms-txt-broken-links` /llms.txt links to URLs that fail — [geo/llms-txt-broken-links](https://void-design.vercel.app/rules/geo/llms-txt-broken-links)
- `llms-txt-not-linked` llms.txt exists but isn't linked from the home page — [geo/llms-txt-not-linked](https://void-design.vercel.app/rules/geo/llms-txt-not-linked)
- `robots-ai-policy` AI crawler policy (allow/deny matrix from robots.txt) — [geo/robots-ai-policy](https://void-design.vercel.app/rules/geo/robots-ai-policy)
- `search-bots-blocked` robots.txt blocks AI search or user-triggered fetchers — [geo/search-bots-blocked](https://void-design.vercel.app/rules/geo/search-bots-blocked)

Detected by `void geo` and `void audit`. Explain it in a terminal: `void rules geo/llms-txt-invalid`