I built this after watching AI agents hit dead links on docs sites and either bail completely or hallucinate an answer from whatever context they had. It kept happening, so I decided to actually fix it.

agent-404 crawls your sitemap, indexes your pages, and when an AI agent hits a 404, it returns the best matching pages as structured JSON-LD so the agent can recover instead of guessing.

One script tag, under 3KB, runs on the edge. One-click deploy to Vercel or Cloudflare Workers. Fully open source.

Try it live: https://agent404.dev/demo

GitHub: https://github.com/bharath31/agent-404