What is The Website Specification (specification.website)?

Updated

The Website Specification is a platform-agnostic, open specification of the technical features a good website should have. It is written for both humans and AI agents, published under the MIT licence, and organised as a checklist of 173 topics across ten categories — from /.well-known/security.txt to WCAG contrast. It is useful if you want a standards-based reference for auditing, learning, or improving a site regardless of what it is built with.

What it actually contains

The spec is a catalogue of technical requirements, not a tutorial series or a product. Each topic is a yes/no checklist item, and each item links back to its source standard — WHATWG, W3C, IETF RFCs, WCAG, MDN, and other bodies defining the modern web. The site states three principles it is built on:

  • Standards, not opinions — every topic traces to a source standard.
  • Platform agnostic — the spec applies whether you ship WordPress, Drupal, TYPO3, Next.js, Astro, Hugo, a Django app, or plain HTML. Implementation hints follow the spec, not the other way round.
  • Built in the open — every page has an "Edit on GitHub" link, PRs are welcome, and sources are credited on every page.

The site reports 869 stars on GitHub and notes a full changelog, with recent additions including auth.md agent registration guidance, a page on status messages, and a page on /.well-known/gpc.json.

The ten categories

Category Topics What it covers
Foundations 20 HTML, head, and document basics every page needs
SEO 14 Search visibility — robots.txt, sitemaps, canonicals, structured data
Accessibility 30 WCAG-aligned rules so people of all abilities can use the site
Security 20 Headers, transport, and policies that keep visitors safe
Well-Known URIs 13 Standard agreed-upon paths under /.well-known/
Agent Readiness 22 Making a site legible to AI agents and crawlers
Performance 26 Core Web Vitals, caching, images, fonts, network behaviour
Privacy 7 Consent, signals, and respecting visitor choice
Resilience 8 Graceful failure — error pages, offline, redirects
Internationalisation 13 Language and locale handling

How to use it

The site describes a three-step loop:

  1. Audit — run the checklist against your site, or let your agent do it. Each item is a yes/no.
  2. Learn — open any item for what it is, why it matters, and how to implement it.
  3. Improve — fix what is missing, then re-check.

There is also a "Get the checklist" entry point alongside the full topic browser.

Agent access

The whole spec is exposed for machine consumption:

  • An open MCP server (read-only, no auth) at https://mcp.specification.website/mcp, configured over HTTP transport.
  • A published Agent Skill that teaches a compatible agent when and how to use the spec.
  • Per-page Markdown via /llms.txt and Accept: text/markdown on any spec URL.

Example MCP configuration as given on the site:

{
  "mcpServers": {
    "specification-website": {
      "transport": "http",
      "url": "https://mcp.specification.website/mcp"
    }
  }
}

When it fits your needs

Use it if you want a vendor-neutral, standards-linked checklist to audit a site or to brief an agent on web requirements. It suits teams working across multiple stacks, since the same spec applies to all of them. It is less suited to someone looking for framework-specific how-to guides or opinionated design advice — the site explicitly positions implementation hints as following the spec rather than leading it.