Agent Ready HTML

The Plain Fetch viewer

In short

The viewer requests a URL the way a plain-fetch agent does: no JavaScript, one request for HTML, one for markdown, one for llms.txt and one for a path that should not exist. It shows the initial HTML on the left, the readable text on the right, and seven flags underneath.

Pre-loaded with www.wikipedia.org, read 4 November 2026. Type any public URL to run your own.

GET https://sentry.io/ answered 200 with text/html, 614 KB, 1 redirect, read 8 November 2026, 13:46 UTC. Final URL: https://sentry.io/welcome/.

Permalink: /viewer/?url=https://sentry.io/

The page answers a plain fetch: 4 of 6 checks found.

Initial HTML what a plain fetch receives

<!DOCTYPE html>
<html lang="en" class="dark"> 
<head>
[... 2 more head elements folded ...]
<title>Application Performance Monitoring &amp; Error Tracking Software | Sentry
</title>
[... 1 more head element folded ...]
<meta name="description" content="Application performance monitoring for developers &amp; software teams to see errors clearer, solve issues faster &amp; continue learning continuously. Get started at sentry.io.">
[... 1 more head element folded ...]
<meta name="robots" content="index, follow">
[... 2 more head elements folded ...]
<link rel="canonical" href="https://sentry.io/welcome/">
[... 20 more head elements folded ...]
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta charset="UTF-8">
[... 1 more head element folded ...]
<link rel="sitemap" type="application/xml" href="https://sentry.io/sitemap-index.xml">
[... 26 more head elements folded ...]
</head> 
<body class="transition-colors duration-200 bg-rich-black text-white"> <a href="#main-content" class="sr-only focus:not-sr-only focus:absolute focus:top-4 focus:left-4 focus:z-50 focus:px-4 focus:py-2 focus:bg-blue-600 focus:text-white focus:rounded">
Skip to main content
</a> 
<header class="sticky top-0 z-50 transition-all duration-200 bg-rich-black" role="banner" aria-label="Site navigation" data-astro-cid-44iojzz6> 
<div class="container" style="--xs: 0%;--sm: 576px;--md: 768px;--lg: 992px;--xl: 1152px;" data-astro-cid-t7cjoelj>  
<nav class="flex flex-row flex-wrap items-center justify-center w-full py-4 xl:flex-nowrap text-white" aria-label="main" role="navigation" data-astro-cid-44iojzz6> <a href="https://sentry.io/welcome/" aria-label="Welcome Page" id="sentry-logo" class="flex items-center flex-shrink-0 mr-auto text-white focus:outline-none focus:fill-pink-500" data-astro-cid-44iojzz6> 
<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 200 44" aria-hidden="true" class="block h-8">[... 1,356 characters folded ...]
</svg> </a> <button class="btn-new silent dark-mode xl:hidden" data-astro-cid-44iojzz6="true" id="menu-toggle-button" aria-expanded="false" aria-controls="mobileMenu" type="button" aria-haspopup="true"><span class="label"> 
Menu
 </span> 
<div class="chevron transition-transform duration-200" aria-hidden="true">
<svg viewBox="0 0 24 24" xmlns="http://www.w3.org/2000/svg">[... 142 characters folded ...]
</svg>
</div></button> 
<div id="mobileMenu" class="xl:hidden w-full bg-rich-black" data-astro-cid-fx6jxwt5> 
<div class="container disable-padding-left disable-padding-right" style="--xs: 0%;--sm: 576px;--md: 768px;--lg: 992px;--xl: 1152px;" data-astro-cid-t7cjoelj>  
<div class="mt-4" data-astro-cid-fx6jxwt5> 
<div class="mb-4" data-astro-cid-fx6jxwt5> 
<div class="collapsible-section bg-rich-black xl:bg-transparent" data-collapsible-section="mobile-0" data-astro-cid-zfo5tgnk> <button class="btn-new subnav dark-mode w-full text-left justify-start flex justify-between items-center xl:hidden collapsible-trigger plausible-event-name=Nav+Click+Product plausible-event-currentUrl=https://sentry.io/w [... 131 characters folded ...]><span class="label">  <span class="label font-medium text-sm leading-[18px] uppercase font-sans" data-astro-cid-zfo5tgnk>Platform</span>  </span> 
<div class="chevron transition-transform duration-200" aria-hidden="true">
<svg viewBox="0 0 24 24" xmlns="http://www.w3.org/2000/svg">[... 142 characters folded ...]
</svg>
</div></button> 
<div id="content-mobile-0" class="xl:block" data-astro-cid-zfo5tgnk> 
<div class="pl-4" data-astro-cid-zfo5tgnk> 
<div data-astro-cid-fx6jxwt5> 
<div data-astro-cid-fx6jxwt5> 
<div class="collapsible-section bg-rich-black xl:bg-transparent" data-collapsible-section="mobile-0-col-0-group" data-astro-cid-zfo5tgnk> <button class="btn-new subnav dark-mode w-full text-left justify-start flex justify-between items-center collapsible-trigger" data-astro-cid-zfo5tgnk="true" id="trigger-mobile-0-col-0-group" aria-expanded="false" aria-controls="content-mobile-0-col-0-group" type="button"><span class="label">  <span class="label font-medium text-sm leading-[18px] uppercase font-sans" data-astro-cid-zfo5tgnk>Products</span>  </span> 
<div class="chevron transition-transform duration-200" aria-hidden="true">
<svg viewBox="0 0 24 24" xmlns="http://www.w3.org/2000/svg">[... 142 characters folded ...]
</svg>
</div></button> 
<div id="content-mobile-0-col-0-group" class="xl:block" data-astro-cid-zfo5tgnk> 
<div class="pl-4" data-astro-cid-zfo5tgnk> 
<div class="linklist-dark" data-astro-cid-5luf6jfd>  
<ul class="list-none p-0 m-0 grid gap-y-5 mt-4 xl:mt-0" data-astro-cid-5luf6jfd> 
<li class="pb-1 pl-6 xl:pl-0" data-astro-cid-5luf6jfd> <a href="https://sentry.io/product/error-monitoring/" data-astro-cid-5luf6jfd="true" class="no-underline font-medium text-sm leading-[18px] uppercase whitespace-nowrap flex items-center gap-x-1.5 w-full min-h-[18px] py-0 [... 159 characters folded ...]> Error Monitoring </a> 
<script nonce="bAEIR5efYHdgvRK2IZEsxf6qYjdwKloz" type="module" src="/_astro/Link.astro_astro_type_script_index_0_lang.CbXevw0m.js?dpl=dpl_CpdcQWz71Ywe4Qg2m5pXSqoebA65">
</script> 
</li>
<li class="pb-1 pl-6 xl:pl-0" data-astro-cid-5luf6jfd> <a href="https://sentry.io/product/logs/" data-astro-cid-5luf6jfd="true" class="no-underline font-medium text-sm leading-[18px] uppercase whitespace-nowrap flex items-center gap-x-1.5 w-full min-h-[18px] py-0.5 hover:und [... 135 characters folded ...]> Logs </a>  
</li>  
</ul> 
</div>
<div class="collapsible-section bg-rich-black xl:bg-transparent" data-collapsible-section="mobile-0-col-0-subdropdown" data-astro-cid-zfo5tgnk> <button class="btn-new subnav dark-mode w-full text-left justify-start flex justify-between items-center collapsible-trigger seer-subdropdown-trigger plausible-event-currentUrl=https://sentry.io/welcome/" data-astro-cid- [... 143 characters folded ...]><span class="label">  <span class="label font-medium text-sm leading-[18px] uppercase font-sans" data-astro-cid-zfo5tgnk>Seer</span>  </span> 
<div class="chevron transition-transform duration-200" aria-hidden="true">
<svg viewBox="0 0 24 24" xmlns="http://www.w3.org/2000/svg">[... 142 characters folded ...]
</svg>
</div></button> 
<div id="content-mobile-0-col-0-subdropdown" class="xl:block" data-astro-cid-zfo5tgnk> 
<div class="pl-4" data-astro-cid-zfo5tgnk>  
<div class="linklist-dark" data-astro-cid-5luf6jfd>  
<ul class="list-none p-0 m-0 grid gap-y-5 mt-4 xl:mt-0" data-astro-cid-5luf6jfd> 
<li class="pb-1 pl-6 xl:pl-0" data-astro-cid-5luf6jfd> <a href="https://sentry.io/product/seer/" data-astro-cid-5luf6jfd="true" class="no-underline font-medium text-sm leading-[18px] uppercase whitespace-nowrap flex items-center gap-x-1.5 w-full min-h-[18px] py-0.5 hover:und [... 135 characters folded ...]> Seer<span class="new-pill" data-astro-cid-2lz6uk62>
NEW
</span> </a>  
</li>
<li class="pb-1 pl-6 xl:pl-0 nested-item" data-astro-cid-5luf6jfd> <a href="https://sentry.io/product/seer/agent/" data-astro-cid-5luf6jfd="true" class="no-underline font-medium text-sm leading-[18px] uppercase whitespace-nowrap flex items-center gap-x-1.5 w-full min-h-[18px] py-0.5 hov [... 147 characters folded ...]> Agent </a>  
</li>
<li class="pb-1 pl-6 xl:pl-0 nested-item" data-astro-cid-5luf6jfd> <a href="https://sentry.io/product/seer/autofix/" data-astro-cid-5luf6jfd="true" class="no-underline font-medium text-sm leading-[18px] uppercase whitespace-nowrap flex items-center gap-x-1.5 w-full min-h-[18px] py-0.5 h [... 151 characters folded ...]> Autofix </a>  
</li>
<li class="pb-1 pl-6 xl:pl-0 nested-item" data-astro-cid-5luf6jfd> <a href="https://sentry.io/product/seer/ai-code-review/" data-astro-cid-5luf6jfd="true" class="no-underline font-medium text-sm leading-[18px] uppercase whitespace-nowrap flex items-center gap-x-1.5 w-full min-h-[18px] p [... 165 characters folded ...]> AI Code Review </a>  
</li>  
</ul> 
</div>  
</div> 
</div> 
</div> 
<script nonce="bAEIR5efYHdgvRK2IZEsxf6qYjdwKloz" type="module">[... 1,299 characters folded ...]
</script>
<div class="linklist-dark" data-astro-cid-5luf6jfd>  
<ul class="list-none p-0 m-0 grid gap-y-5 mt-4 xl:mt-0" data-astro-cid-5luf6jfd> 
<li class="pb-1 pl-6 xl:pl-0" data-astro-cid-5luf6jfd> <a href="https://sentry.io/product/session-replay/" data-astro-cid-5luf6jfd="true" class="no-underline font-medium text-sm leading-[18px] uppercase whitespace-nowrap flex items-center gap-x-1.5 w-full min-h-[18px] py-0.5 [... 155 characters folded ...]> Session Replay </a>  
</li>
<li class="pb-1 pl-6 xl:pl-0" data-astro-cid-5luf6jfd> <a href="https://sentry.io/product/metrics/" data-astro-cid-5luf6jfd="true" class="no-underline font-medium text-sm leading-[18px] uppercase whitespace-nowrap flex items-center gap-x-1.5 w-full min-h-[18px] py-0.5 hover: [... 141 characters folded ...]> Metrics<span class="new-pill" data-astro-cid-2lz6uk62>
NEW
</span> </a>  
</li>  
</ul> 
</div>
<div class="collapsible-section bg-rich-black xl:bg-transparent" data-collapsible-section="mobile-0-col-0-bottom-1" data-astro-cid-zfo5tgnk> <button class="btn-new subnav dark-mode w-full text-left justify-start flex justify-between items-center collapsible-trigger" data-astro-cid-zfo5tgnk="true" id="trigger-mobile-0-col-0-bottom-1" aria-expanded="false" aria-controls="content-mobile-0-col-0-bottom-1" type="button"><span class="label">  <span class="label font-medium text-sm leading-[18px] uppercase font-sans" data-astro-cid-zfo5tgnk>Tracing</span>  </span> 
<div class="chevron transition-transform duration-200" aria-hidden="true">
<svg viewBox="0 0 24 24" xmlns="http://www.w3.org/2000/svg">[... 142 characters folded ...]
</svg>
</div></button> 
<div id="content-mobile-0-col-0-bottom-1" class="xl:block" data-astro-cid-zfo5tgnk> 
<div class="pl-4" data-astro-cid-zfo5tgnk>  
<div class="linklist-dark" data-astro-cid-5luf6jfd>  
<ul class="list-none p-0 m-0 grid gap-y-5 mt-4 xl:mt-0" data-astro-cid-5luf6jfd> 
<li class="pb-1 pl-6 xl:pl-0" data-astro-cid-5luf6jfd> <a href="https://sentry.io/product/tracing/" data-astro-cid-5luf6jfd="true" class="no-underline font-medium text-sm leading-[18px] uppercase whitespace-nowrap flex items-center gap-x-1.5 w-full min-h-[18px] py-0.5 hover: [... 141 characters folded ...]> Tracing </a>  
</li>
<li class="pb-1 pl-6 xl:pl-0 nested-item" data-astro-cid-5luf6jfd> <a href="https://sentry.io/product/tracing/ai-agent/" data-astro-cid-5luf6jfd="true" class="no-underline font-medium text-sm leading-[18px] uppercase whitespace-nowrap flex items-center gap-x-1.5 w-full min-h-[18px] py-0 [... 159 characters folded ...]> Agent Tracing </a>  
</li>  
</ul> 
</div>  
</div> 
</div> 
</div> 
<div class="linklist-dark" data-astro-cid-5luf6jfd>  
<ul class="list-none p-0 m-0 grid gap-y-5 mt-4 xl:mt-0" data-astro-cid-5luf6jfd> 
<li class="pb-1 pl-6 xl:pl-0" data-astro-cid-5luf6jfd> <a href="https://sentry.io/product/profiling/" data-astro-cid-5luf6jfd="true" class="no-underline font-medium text-sm leading-[18px] uppercase whitespace-nowrap flex items-center gap-x-1.5 w-full min-h-[18px] py-0.5 hove [... 145 characters folded ...]> Profiling </a>  
</li>
<li class="pb-1 pl-6 xl:pl-0" data-astro-cid-5luf6jfd> <a href="https://sentry.io/product/size-analysis/" data-astro-cid-5luf6jfd="true" class="no-underline font-medium text-sm leading-[18px] uppercase whitespace-nowrap flex items-center gap-x-1.5 w-full min-h-[18px] py-0.5  [... 153 characters folded ...]> Size Analysis </a>  
</li>
<li class="pb-1 pl-6 xl:pl-0" data-astro-cid-5luf6jfd> <a href="https://sentry.io/product/cron-monitoring/" data-astro-cid-5luf6jfd="true" class="no-underline font-medium text-sm leading-[18px] uppercase whitespace-nowrap flex items-center gap-x-1.5 w-full min-h-[18px] py-0. [... 157 characters folded ...]> Cron Monitoring </a>  
</li>
<li class="pb-1 pl-6 xl:pl-0" data-astro-cid-5luf6jfd> <a href="https://sentry.io/product/uptime-monitoring/" data-astro-cid-5luf6jfd="true" class="no-underline font-medium text-sm leading-[18px] uppercase whitespace-nowrap flex items-center gap-x-1.5 w-full min-h-[18px] py- [... 161 characters folded ...]> Uptime Monitoring </a>  
</li>
<li class="pb-1 pl-6 xl:pl-0" data-astro-cid-5luf6jfd> <a href="https://labs.sentry.dev/" target="_blank" rel="noopener noreferrer" data-astro-cid-5luf6jfd="true" class="no-underline font-medium text-sm leading-[18px] uppercase whitespace-nowrap flex items-center gap-x-1.5 w [... 163 characters folded ...]> Labs<span class="new-pill" data-astro-cid-2lz6uk62>
NEW
</span> </a>  
</li>  
</ul> 
</div> 
</div> 
</div> 
</div>  
</div>
<div data-astro-cid-fx6jxwt5> 
<div class="collapsible-section bg-rich-black xl:bg-transparent" data-collapsible-section="mobile-0-col-2-item-0" data-astro-cid-zfo5tgnk> <button class="btn-new subnav dark-mode w-full text-left justify-start flex justify-between items-center collapsible-trigger" data-astro-cid-zfo5tgnk="true" id="trigger-mobile-0-col-2-item-0" aria-expanded="false" aria-controls="content-mobile-0-col-2-item-0" type="button"><span class="label">  <span class="label font-medium text-sm leading-[18px] uppercase font-sans" data-astro-cid-zfo5tgnk>Integrations</span>  </span> 
<div class="chevron transition-transform duration-200" aria-hidden="true">

Shown with 342 long blocks (scripts, styles, long tags) folded into a marker that says how many characters they hide; line breaks added before block tags because the source is minified; the pane stops after the first 200 words; the page is 614 KB.

Reading view the text a plain-fetch client can extract

title: Application Performance Monitoring & Error Tracking Software | Sentry

Code breaks, fix it faster

Skip to main content Menu Platform Products Error Monitoring Logs Seer Seer NEW Agent Autofix AI Code Review Session Replay Metrics NEW Tracing Tracing Agent Tracing Profiling Size Analysis Cron Monitoring Uptime Monitoring Labs NEW Integrations Github Slack Sentry CLI Sentry MCP All Integrations Solutions Solutions Web / Full Stack Development Mobile Crash Reporting Game Crash Reporting AI Observability Application Performance Monitoring Application Observability Real User Monitoring Ecommerce OpenTelemetry Enterprise Startups All SDKs Resources Learn Blog Changelog Sandbox Resources Syntax Customers Cookbook Support Contact Us Help Center Status Hang out with us Community Events Merch Docs Pricing Sign In Get Demo Get Started Platform Products Products Error Monitoring Logs Session Replay Metrics NEW Tracing Agent Tracing Profiling Size Analysis Cron Monitoring Uptime Monitoring Labs NEW Products Error Monitoring Logs Session Replay Metrics NEW Tracing Agent Tracing Profiling Size Analysis Cron Monitoring Uptime Monitoring Labs NEW AI Debugging AI Debugging Seer NEW Agent Autofix AI Code Review AI Debugging Seer NEW Agent Autofix AI Code Review Integrations Integrations Github Slack Sentry CLI Sentry MCP All Integrations Integrations Github Slack Sentry CLI Sentry MCP All Integrations Solutions Web / Full Stack Development Mobile Crash Reporting Game Crash Reporting AI Observability Application Performance

2338 more words follow in the initial HTML.

4 found, 1 missing, 2 notes, from 7 checks run

  • H1Found
  • 200 wordsFound
  • llms.txtNote
  • MarkdownFound
  • Missing pathMissing
  • JSON-LDFound
  • OpenAPINote
What a plain fetch found on sentry.io
CheckResultDetail
H1 in the initial HTMLFound one H1First H1: Code breaks, fix it faster
First 200 words in the initial HTMLFound 200 of 200 wordsThe initial HTML carries 2538 words of visible text; the first 200 are marked in the left pane.
llms.txt present and linkedNote present, not linked93292 bytes, 498 links. Structure grade A (6 of 6). Nothing on the home page points to it. Ora's lab found 86 percent of llms.txt fetches arrived through a link.
Markdown on requestFound text/markdownAccept: text/markdown returned 200 with text/markdown. Vary: Accept is not set, so a cache can serve the wrong form.
Status of a made-up pathMissing 200 (soft 404)/agent-ready-html-missing-path-check returned 200. A missing page that answers 200 looks like a live page to an agent.
JSON-LD typesFound Organization, PostalAddress, WebPage3 schema.org types in JSON-LD blocks on the home page: Organization, PostalAddress, WebPage.
OpenAPI linkNote none on the home pageNo OpenAPI link on the home page. It matters only for a site that ships an API.

Run the full check

The viewer read one page with four requests. The full check we recommend next is Ora's scan. Its Access layer runs 42 checks worth 30 of its 100 points, among them content without JavaScript, bot detection, llms.txt, markdown on request, JSON-LD and the sitemap (Ora's check catalogue, contract 1.38.0, read 5 November 2026). Open Ora's report for sentry.io.

Limits: Ora reads public URLs only, says two runs of one scan land within a couple of points without publishing repeat-scan data, and keeps the product that fixes what it finds behind a waitlist. Cloudflare's scanner at isitagentready.com is a quick free alternative, and Mintlify's score covers documentation.

What the viewer does

It sends four plain GET requests with the user agent Mozilla/5.0 (compatible; agent-readiness-crawl/1.0): the URL itself, the same URL with Accept: text/markdown, /llms.txt on the same host, and a made-up path at the root. It runs no JavaScript. The left pane is the first bytes of the HTML as text, with long scripts and styles folded into a marker that says how many characters they hide. The H1 and the first 200 words of visible text are marked in both panes. The flags under the panes say what the four responses added up to.

Limits

  • Ten seconds for all four requests together, 1.5 MB read from the home page, at most five redirects, each one checked again.
  • http and https only, default ports only. Private, local and internal addresses and names are refused.
  • Ten runs per address per minute. The counter lives in memory on the edge function, so it is per instance rather than global. Past ten you get a 429 with a Retry-After header.
  • Results are cached for 24 hours by the response headers. Nothing is written to a database: the viewer keeps the first 200 words and the extracted fields for the length of the request and keeps no page body beyond that.

What it does not tell you

A plain fetch from this server is not a real agent. Bot protection weighs the source address more than the user agent, so a page that answers 200 here can still refuse an agent, and the reverse. Ora's lab found (2026-10-19) that returning 403 to agent user agents and hiding the answer in JavaScript were the only two of 19 configurations that stopped retrieval; the viewer can see the second, and can only hint at the first. The initial HTML reference covers both. The server logs and the published crawler address ranges settle the first.

The seven flags

H1 in the initial HTML
Whether the HTML the server sends already contains an H1. It is the cheapest sign that the page does not depend on scripts to say what it is.
First 200 words in the initial HTML
Whether at least 200 words of visible text arrive in the initial HTML. Under 40 words with an app root element is flagged as a JavaScript shell.
llms.txt present and linked
Whether /llms.txt answers with a plain-text file, whether the home page links it (an anchor, a link element or a Link header), and the structure grade the index uses.
Markdown on request
Whether a request with Accept: text/markdown comes back as text/markdown. Cloudflare Radar found 3.9 percent of scanned top sites passing this at its April 2026 launch.
Status of a made-up path
Whether a path that should not exist returns 404 or 410. A 200 is a soft 404 and reads as a live page.
JSON-LD types
The schema.org types found in JSON-LD blocks on the page. Ora's lab found JSON-LD made no difference when the answer was already in the HTML.
OpenAPI link
Whether the page links an OpenAPI file, by an anchor or a service-desc link relation. It matters only for a site that ships an API.

Sources

  1. Ora: AgentReady launch post (Ora's lab findings) https://ora.ai/blog/agentready-launch, read 4 November 2026
  2. Ora check catalogue, contract 1.38.0 (132 checks, 42 in the Access layer) https://ora.ai/api/checks, read 5 November 2026
  3. Ora home page (the fixing product is behind a waitlist) https://ora.ai/, read 5 November 2026
  4. Ora: Introducing Deep Scan (repeat scans) https://ora.ai/blog/introducing-deep-scan, read 5 November 2026
  5. Ora llms.txt (public URLs only) https://ora.ai/llms.txt, read 5 November 2026
  6. Vercel: Make your site readable by AI agents https://vercel.com/kb/guide/make-your-site-readable-by-ai-agents, read 4 November 2026
  7. llms.txt proposal (llmstxt.org) https://llmstxt.org/, read 4 November 2026

Last reviewed 5 November 2026