# Agent-friendly 404s

Check id `agent-friendly-404` · Readability · runs in the free CLI · pre-release, in calibration

**What we look for.** What an agent gets on a path that doesn't exist: a real 404 status, and whether the error body is readable Markdown.

**Why it matters.** A 200 that says 'not found' looks like content. A clear 404 with a short explanation tells the agent where to go next.

**How to pass.** Return 404 or 410 for missing pages and, for agents, a short Markdown body that links your docs or llms.txt.

Run it: `npx backwatch your-site.com --pillar readability` and find `agent-friendly-404` in the report.