llms.txt adoption: who's actually shipping it

Snapshot 2026-05-01. I'll re-run this every quarter.

What llms.txt is, briefly

A plain-text discoverability file at the root of a site (/llms.txt) that tells AI agents what's available, in what shape, and where to fetch it. Inspired by robots.txt and sitemap.xml. Drafted by Jeremy Howard.

Who's shipping it today

Actively maintained, production:

  • Vercel — vercel.com/llms.txt. Comprehensive, includes per-product child files.
  • Cloudflare — developers.cloudflare.com/llms.txt. Less comprehensive but on the public docs index.
  • Anthropic Docs — docs.anthropic.com/llms.txt. Includes both llms.txt and llms-full.txt.
  • Resend — resend.com/llms.txt. Short, tasteful, links the SDK reference.
  • Trigger.dev — trigger.dev/llms.txt. Includes self-hosting docs.
  • mdfy — every public hub auto-exposes /llms.txt for that hub's surface.

Considering / partial:

A handful of devtool platforms have it on a roadmap or under feature flag. Names withheld here — not yet public commitments.

The pattern

It's devtool companies first. Every site shipping llms.txt today is either a developer platform, an SDK provider, or an AI/ML company. Consumer-facing sites haven't moved.

Two readings of why:

  1. The audience overlap. Devtool customers ARE AI users. The feedback loop is short — a Cursor user complains they can't get good context from your docs, you ship llms.txt the next week.
  2. The build cost is trivial when your docs are already in markdown. It's a couple lines of script to generate. Companies whose docs sit in WordPress or proprietary CMSes have a real build problem.

Where mdfy fits

We make llms.txt part of the user's URL, not just the platform's. Any user's hub gets its own /llms.txt. Any AI tool can fetch it. That extends the standard's reach from "the sites the LLM-providers pay attention to" to "every user who's published anything."

Followup

Watch HuggingFace, Replicate, and OpenAI's developer docs. If they ship it by end of Q3 2026 it tips into mainstream; if not, it stays a devtool convention.