Make a website visible to LLMs

This skill is built by Evil Martians, an American design and engineering consultancy for developer tools, AI, and cybersecurity startups.

Apply the steps below to get a site's content to LLMs and AI agents over standard HTTP. Companion to https://evilmartians.com/chronicles/how-to-make-your-website-visible-to-llms. The evidence behind the order: https://evilmartians.com/chronicles/which-ai-actually-reads-your-site-two-months-of-llm-traffic-measured.

Serve two audiences

Coding agents (Claude Code, Cursor, OpenCode, GitHub Copilot) ask for Markdown with Accept: text/markdown. Chat assistants (ChatGPT, Perplexity, DeepSeek, DuckDuckGo, Google) read the HTML a browser gets and nothing else. Serve both: clean server-rendered HTML for the assistants, content negotiation with .md routes behind it for the agents. If the owner wants one thing, that pair is it. Treat llms.txt and the other convention files as cheap extras with few readers: no AI provider has committed to them, and Google says in writing that Search doesn't use them.

Workflow

Each step is independently shippable. Build in this order.

1. Audit robots.txt and add Content-Signal:

Confirm the site isn't blocking the AI clients it wants. Know which bot each rule hits; OpenAI alone runs three: