llms-full.txt present
What it checks
llms-full.txt provides the complete content of your site in a single file, allowing AI agents to ingest everything in one request instead of crawling page by page.
Why it matters
Publishing /llms-full.txt containing the site’s complete documentation as one markdown file causes AI agents to ingest the full corpus in a single fetch, improving answer accuracy versus llms.txt alone.
Evidence
/llms-full.txt
This is the weakest signal in the domain. It is not in the spec at all — both llmstxt.org v2 and its changes page and llms-full.txt appears in neither; it is a community extension popularized when Mintlify enabled it platform-wide in Nov 2024. Adoption is marginal and purely derivative: 15 of the Tranco top 1,000 (1.5%), and tellingly zero sites publish llms-full.txt without also publishing llms.txt, meaning no one adopts it on its own merits.
Google’s Lighthouse gatherer does not fetch it (source verified: root /llms.txt only). No vendor documentation from OpenAI, Anthropic, Google or Perplexity references consuming it. The single pro-claim is Mintlify relaying Profound’s assertion that ‘LLMs are accessing llms-full.txt even more frequently than the original llms.txt’ — with no sample size, no methodology, and no dataset, from a vendor that sells the feature.
Limits
A measurement taken for this dossier is close to disqualifying. Anthropic’s llms-full.txt is 33.5 MB, Cloudflare’s is 57.3 MB, OpenAI’s 6.1 MB, Perplexity’s 4.1 MB. At roughly 4 characters per token these are about 8M, 14M, 1.5M and 1M tokens. That is one to two orders of magnitude beyond any production context window. The stated mechanism, single-fetch full ingestion, is therefore physically impossible for the very sites held up as exemplars.
Stripe returns 404 for it while maintaining a 92 KB llms.txt, suggesting deliberate rejection. Mintlify caps auto-generated llms.txt at 100,000 characters but applies no cap to llms-full.txt, which is how these files reach absurd sizes. Serving a 57 MB file to any agent that requests it is also a real bandwidth and abuse liability.
Sources
- The /llms.txt file — link relation guidance — Answer.AI (Jeremy Howard), spec (verified 2026-08-21)
- llms.txt v2 changes page — Jeremy Howard / Answer.AI, draft-spec (verified 2026-08-20)
- llms.txt — Mintlify documentation — Mintlify, vendor-doc (verified 2026-08-20)
- The value of llms.txt: Hype or real? — Mintlify, article (verified 2026-08-20)
- LLMS.txt Adoption Tracker (Tranco top 1,000) — Rankability, dataset (verified 2026-08-20)
- Lighthouse core/gather/gatherers/agentic/llms-txt.js (source code) — Google Chrome / Lighthouse, vendor-doc (verified 2026-08-20)