Definition
llms.txt is a proposed convention: a Markdown file at a site’s root listing its important pages for AI systems. Adoption has grown quickly, but current measurement shows AI crawlers largely ignore it and fetch HTML directly instead.
A study across roughly 300,000 domains found no statistically significant correlation between having the file and AI citation frequency. A separate analysis of about 137,000 domains found 97% of published llms.txt files received zero AI-bot requests.
The audience that does reliably fetch it is developer tooling — coding agents and IDE assistants pointed at a domain. That is a real if modest use, and a reasonable justification for keeping one current.
The usual error
Where this goes wrong in practice
Selling it, or buying it, as an AI-citation tactic. On the available evidence it is a developer convenience.
Related terms
Retrieval-augmented generation (RAG)
Retrieval-augmented generation is an architecture where a language model answers using documents fetched at query time rather than relying only on training data. The system splits sources into chunks, embeds and ranks them, places the best matches into the model’s context, and generates an answer from those.
DefinitionGenerative engine optimization (GEO)
Generative engine optimization is the practice of improving how a source is used by AI systems that synthesise answers rather than list links. The term comes from a 2023 academic paper (arXiv:2311.09735, later accepted at KDD 2024) that measured how often a document’s content was reflected in a generated answer.
DefinitionAgentic workflow
An agentic workflow is an automation where a language model completes several connected steps toward a goal — researching, classifying, drafting, routing, reporting — deciding the order within defined rules, rather than executing a fixed script. Human approval points are part of the design, not an afterthought.
DefinitionAI Overviews
AI Overviews are Google-generated summaries shown above traditional results for some queries, assembled from pages in the ordinary search index and shown with links to the sources used. Eligibility requires that a page is already indexable and snippet-eligible in normal Search.
DefinitionAnswer engine optimization (AEO)
Answer engine optimization is structuring content so a direct answer can be lifted cleanly into a featured snippet, a People Also Ask entry, a voice response or an AI summary. It predates the current AI wave — the original concern was voice assistants — and overlaps heavily with both SEO and GEO.
DefinitionLLMO, AISO and GSO
LLMO, AISO and GSO are vendor terms for largely the same work as GEO and AEO: making content that AI systems can read, trust and reference accurately. No academic or platform-official definition separates them, and industry sources contradict each other on where the boundaries fall.
DefinitionPrompt injection
Prompt injection is an attack where instructions hidden in content an AI system reads — a web page, an email, a document, a form submission — are treated by the model as commands rather than data. It is the main security concern for any agent that ingests untrusted input.
Definition