www.johnlewis.com
Scored by v3 · source-of-truth hashes: score db860d6ac94e · thresholds e94f8b33e500 — verifiable against the canonical scorer.
The 28-day score is the p75 of nightly runs — the stable number to cite. Deterministic metrics (CRR/SSD/TC) show their latest value (they move only when the site changes); timing (TTFUT) and answer-fidelity (AF) are smoothed by 28-day p75 — the same lab-vs-field split Core Web Vitals uses. Synthetic daily measurement, not real-user field data.
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An agent is likely to fabricate missing details rather than say “I don’t know”. 2/7 applicable facts come from machine-readable structured data.
Metrics
Token Cost breakdown
Where the page's tokens go (≈6,175 across regions). Most tokens are real content — the agent isn't paying much for chrome.
Final screenshot
Diagnostics
pre-JS raw HTML
Fix: Server-render or statically generate the main content so a non-JS agent still receives it; make client rendering a progressive enhancement, not the source of truth.
content vs chrome/boilerplate
Fix: Wrap the real content in <main>/<article>, cut repeated nav/boilerplate, and keep the primary content dense and early in the DOM.
Rendered profile: headless
Metrics
Token Cost breakdown
Where the page's tokens go (≈6,060 across regions). Most tokens are real content — the agent isn't paying much for chrome.
Final screenshot
Diagnostics
pre-JS raw HTML
Fix: Server-render or statically generate the main content so a non-JS agent still receives it; make client rendering a progressive enhancement, not the source of truth.
content vs chrome/boilerplate
Fix: Wrap the real content in <main>/<article>, cut repeated nav/boilerplate, and keep the primary content dense and early in the DOM.
Rendered profile: headless
Access & discovery checks — separate from the gated CAV metrics above. Click an issue for business impact, what we measured, and how to fix. · Take the Agent Readiness course →
Agent files & endpoints
Issues (6)
✗ llms.txt present high impact Absent at /llms.txt and /.well-known/llms.txt
Business impact llms.txt is the robots.txt for AI: it tells agents what your site is, what matters, and where to find it. Without it AI guesses — and guessing means inaccurate recommendations and lost visibility.
What we measured We fetch /llms.txt and /.well-known/llms.txt and validate the spec (H1 title + a one-line blockquote summary). We also note /llms-full.txt (your full content as Markdown).
How to fix Create /llms.txt with a short summary + key pages; optionally /llms-full.txt with full content in Markdown.
# Your Site
> One-line description for AI agents.
## Key pages
- /products — catalog
- /pricing — plans
- /docs — documentationSpec: https://llmstxt.org
✗ XML sitemap present medium impact No /sitemap.xml
Business impact A sitemap is your table of contents for AI crawlers. Without it agents follow homepage links and miss deep pages (products, docs, pricing) — shrinking what they can recommend.
What we measured We fetch /sitemap.xml (and /sitemap_index.xml), confirm valid XML with <loc> entries, and check <lastmod> freshness.
How to fix Generate an XML sitemap of all public pages with current lastmod dates and reference it in robots.txt.
# robots.txt
Sitemap: https://example.com/sitemap.xml~ Server response (TTFB) low impact 922ms (good ≤800, warn ≤1800)
Business impact Slow servers cause agents to time out and move on. Fast response keeps you in the running.
What we measured We time the response (time-to-first-byte) against good (<800ms) / warn (<1800ms) thresholds.
How to fix Use a CDN, caching and an optimized origin to get TTFB under 800ms.
Spec: https://web.dev/ttfb/
~ agents.json discovery low impact Absent (emerging standard)
Business impact agents.json describes what your site can DO for agents (services, endpoints, capabilities) — an emerging discovery standard. Early adopters get native agent integration.
What we measured We check /agents.json and /.well-known/agents.json for a valid configuration.
How to fix Publish /agents.json describing your site's capabilities and actions.
~ WebMCP endpoint low impact Absent (emerging standard)
Business impact WebMCP lets agents call actions on your site directly (book, buy, query) instead of scraping the DOM. Early adopters get native AI-agent interoperability.
What we measured We check /.well-known/webmcp and /webmcp.json for a valid actions array.
How to fix Add a WebMCP endpoint exposing your key actions to agents.
Spec: https://webmcp.org
~ API documentation low impact No OpenAPI/Swagger found
Business impact Programmatic agents prefer a typed API. An OpenAPI/Swagger spec lets them integrate without scraping.
What we measured We probe /openapi.json, /swagger.json, /api-docs and /.well-known/openapi.json.
How to fix Publish an OpenAPI spec at a well-known path.
Passed audits (6)
Transport & Trust (SEC 1.0.0)
HTTPS, HSTS, CSP, sniffing, referrer and CORS posture. Diagnostic only — this does not affect the CAV score. A security header does not make a page more legible to an agent, so scoring it would reward a CDN toggle that changes nothing an agent can recover. We measure it and say so.
Per-header findings (6)
| Header | Evidence |
|---|---|
| ✅ HTTPS | served over HTTPS |
| ✅ HSTS | max-age=31708800 |
| ❌ Content-Security-Policy | no content-security-policy header |
| ✅ X-Content-Type-Options | nosniff |
| ⚠️ Referrer-Policy | no referrer-policy header (browser default applies) |
| ➖ CORS exposure | no CORS headers on the document (normal for an HTML page) |
A deeper scan (a second render, ~30–60s): network waterfall, unused JavaScript, long tasks, and prioritized fixes. Runs only when you ask; the result is cached so it never re-runs.