# Fix: 404 body is markdown with a recovery link

> Web-audit fix skill for the `agent-friendly-404-md` check (Discoverability, SHOULD).

## Goal

Serve a short markdown 404 that links at least one agent recovery surface.

## Fix

When `Accept: text/markdown` hits an unknown path, return 404 or 410 with a short markdown
body that includes at least one recovery link: sitemap, `llms.txt`, a docs index, or an
equivalent same-origin href. Linking both sitemap and `llms.txt` as absolute URLs is the
stronger pattern. Zero links is a miss even when the status is correct.

## Resources

- [llmstxt.org](https://llmstxt.org/)

## Copy-paste prompt

Paste this into your coding agent. [Your audit](https://anc.dev/audit) adds what it observed for this check:

```text
Goal: Serve a short markdown 404 that links at least one agent recovery surface
Fix: When `Accept: text/markdown` hits an unknown path, return 404 or 410 with a short markdown body that includes at least one recovery link: sitemap, `llms.txt`, a docs index, or an equivalent same-origin href. Linking both sitemap and `llms.txt` as absolute URLs is the stronger pattern. Zero links is a miss even when the status is correct.
Skill: https://anc.dev/fix/agent-friendly-404-md
Docs: https://llmstxt.org/
```

## Verify

Re-run the audit at [https://anc.dev/audit](https://anc.dev/audit) or call the `audit_website` MCP tool; the `agent-friendly-404-md` check should report `pass`.