The short answer
llms.txt is a Markdown file at your site's root that gives AI agents a short, curated summary of your site and links to your most useful pages. It's quick to add, and Chrome's Lighthouse now checks for it. But Google says you don't need it to appear in AI Overviews, and it won't rescue weak content.
Key takeaways
- llms.txt is a proposed convention, not a ranking signal for Google Search.
- It helps AI agents that browse your site understand its structure.
- Worth an hour once crawlability, positioning, and answer-first pages are in place.
Few files have been oversold and dismissed as loudly as llms.txt. Some vendors call it essential. Some SEOs call it pointless. Both camps are partly right.
Here's the plain version, with the receipts.
What is llms.txt?
It's a proposed convention, not a formal standard. Jeremy Howard published the proposal in September 2024, describing it as a way to give agents a brief overview of a site, with background, guidance, and links to detailed Markdown files.1
The format is simple Markdown, placed at /llms.txt:
- An H1 with the site or company name. This is the only required part.
- A blockquote with a one or two sentence summary.
- Optional notes that help an agent understand the site.
- H2 sections of links, each written as [Page name](url): what it covers.
- An "Optional" section for secondary links an agent can skip.1
A B2B SaaS example might look like this:
# Acme Compliance > Acme automates SOC 2 and ISO 27001 compliance for B2B SaaS companies. ## Product - [How Acme works](https://acme.com/product): Overview of automated evidence collection - [Pricing](https://acme.com/pricing): Plans and what each includes ## Optional - [Blog](https://acme.com/blog): Guides on compliance programs
Does Google use llms.txt?
For Search, no. For Chrome's developer tools, now partly. The two positions sit side by side.
| Date | Who | What they said or did |
|---|---|---|
| 5 May 2026 | Chrome Lighthouse | Added an llms.txt audit under agentic browsing. It fails only if the file returns a server error, and is marked not applicable if there's no file, because the file is "optional at the moment."2 |
| 10 Dec 2025 | Google Search Central | Says you don't need new machine-readable files, AI text files, or special markup to appear in AI Overviews or AI Mode.3 |
| 17 Jun 2025 | John Mueller, Google | Wrote on Bluesky that no AI system currently used llms.txt.4 |
Table 1. What Google has said and done about llms.txt.
Read together, the message is consistent. llms.txt isn't a ranking signal for Google Search. It's a convenience for AI agents that browse sites, and Google's Lighthouse documentation says that without it, agents may spend more time crawling to understand a site's structure.2
Who should publish one, and who can wait?
- Publish one if: your product has documentation, an API, or integrations that agents and developers' AI tools read. A clean index of those pages is useful.
- It's a nice-to-have if: you're a typical B2B SaaS marketing site. It takes an hour, costs nothing, and makes your site's structure explicit. Just don't expect it to move rankings or citations on its own.
- Fix these first: crawlability, clear positioning, and answer-first pages. Those are what AI engines actually read.
An llms.txt that describes your product differently from your homepage creates the inconsistency AI engines struggle with. Copy your one-line description from your site, word for word.
How do you write one in an hour?
Start with your one-line description
Use the exact sentence from your homepage.
Pick 10 to 20 pages that matter most
Product, pricing, use cases, comparisons, security, docs, and your best guides.
Write one plain line per link
Say what the page covers, not why it's great.
Put secondary pages under "Optional"
Blog archives, careers, and press go here.
Publish at /llms.txt and test it
Make sure it loads without a server error, then run Lighthouse to confirm.
Review the file every quarter, when you update your positioning or launch a new product line. A stale llms.txt is worse than none.
Read next: AEO, GEO, and SEO: what's actually different? And grab our free llms.txt kit in the Agency Toolkit.
The bottom line
llms.txt isn't a shortcut. It's a tidy front door for machines. Worth an hour, not a strategy.
Sources
- Jeremy Howard, The /llms.txt file, proposal first published September 3, 2024. llmstxt.org/
- Chrome for Developers, llms.txt (Lighthouse agentic browsing audit), last updated May 5, 2026. developer.chrome.com/docs/lighthouse/agentic-browsing/llms-txt
- Google Search Central, AI features and your website, last updated December 10, 2025. developers.google.com/search/docs/appearance/ai-features
- Search Engine Roundtable, Google: No AI System Currently Uses LLMs.txt, reporting John Mueller's Bluesky post of June 17, 2025. seroundtable.com/google-ai-llms-txt-39607.html
About the author
Aimee van der Haar
Aimee founded Bearly Creative to give great startups and tech companies the marketing they deserve. She works across strategy, design, content, and AI search, and she still does the work herself.
