Beyond llms.txt for Agent Readability

A friend pointed me at a14y.dev, which scans your site for "agent readability" and hands back a scored fix-list. It's the obvious next thing after llms.txt, and the suggestions are sharper than I expected.

The scorecard is 38 checks pinned at v0.2.0, split across discoverability, parsing, and comprehension. Some are the ones you'd guess: llms.txt exists, robots allows AI bots, canonical links, lang attributes, JSON-LD breadcrumbs. The interesting ones are the suggestions I hadn't seen pushed as a standard yet.

The less obvious suggestions

A Markdown mirror of every page, served at the same URL with a .md suffix, plus a <link rel="alternate" type="text/markdown"> in the HTML head so agents can find it without guessing. Content negotiation on the canonical URL so a request with Accept: text/markdown gets the Markdown directly. A glossary page, because agents resolving acronyms and project-specific terms benefit from one canonical place to look. Language tags on every code block. A /sitemap.md alongside the XML one.

None of these are exotic. They're the kind of thing you'd do for a thoughtful human reader, just written down as pass/fail checks.

The loop they're pushing

The CLI ships with an --output agent-prompt mode that writes a Markdown brief aimed at a coding agent: every failure, its detection rule, the fix, and a link back to the scorecard page. The intended workflow is to pipe that into Claude Code or Codex, let it patch, then re-run with --fail-under 80 in CI. There's also a skills add package for agents that speak the open skills format.