Content efficiency

What it checks

The extension fetches the page’s HTML and measures how much of it is readable text. It strips <script> and <style> blocks and every tag, then divides the length of the text that is left by the length of the whole HTML response. The check passes when text makes up at least 5% of the HTML.

Below that, markup dominates: an agent pays for thousands of bytes of wrappers, inline scripts and hydration data to get at a small amount of content.

Results

Status	When
Pass	Readable text is 5% or more of the HTML
Warn	Readable text is less than 5% of the HTML
Unmeasured	The page’s HTML could not be fetched

How to fix

Reduce the markup around your content rather than adding more text:

• Move large inline <script> and <style> blocks into external files.
• Server-render the content instead of shipping it inside a large JSON hydration blob alongside an empty shell.
• Keep wrapper nesting shallow; ten nested <div> elements around a paragraph add bytes and no meaning.

A related check, Page token budget, looks at the opposite problem: a page with so much text that an agent cannot read all of it.

Support by agent and browser

Announced means the vendor’s own docs or announcement say so. Published is the date on the vendor’s own page, where it has one. Checked is the last time our weekly research found that page still saying so.

Agent	Status	Source
AI assistants
Claude Anthropic	Partial support	partial Claude API docs: Web fetch tool Undated · Checked 9 Oct 2026Docs: 'The web fetch tool currently does not support websites dynamically rendered with JavaScript.' Content returned as extracted text; content shipped only in client-side hydration is not seen.
Coding agents
Claude Code Anthropic	Supported (announced)	Claude Code CHANGELOG.md (anthropics/claude-code) Published 21 Apr 2026 · Checked 9 Oct 2026v2.1.117 (npm release 2026-04-21): 'Fixed WebFetch hanging on very large HTML pages by truncating input before HTML-to-markdown conversion' — size of raw HTML, not just text, determines what survives.

No evidence yet25

• ChatGPT
• Gemini
• Perplexity
• Copilot
• Meta AI
• ChatGPT Atlas
• Comet
• Dia
• Gemini in Chrome
• Edge Copilot Mode
• Cursor
• Codex
• GitHub Copilot
• Windsurf
• CCBot
• Applebot
• Amazonbot
• Bytespider
• Cohere
• Mistral
• DuckAssist
• Chrome
• Edge
• Firefox
• Safari

Names and marks belong to their owners and are used only to identify products. None of these vendors is affiliated with Sitebulb. Spotted something out of date? Send a correction.

Adoption on the top 100 sites

100%

83 of 83 measured sites implement it

Scanned 23 Oct 2026 with the Sitebulb Labs extension, against the Tranco list (tranco-56Z8N). 17 sites couldn’t be measured (bot challenge or timeout) and are left out of the share.

Sites implementing it83

1. #1 google.com (with warnings)
2. #2 cloudflare.com (with warnings)
3. #3 aws.amazon.com (via amazonaws.com) (with warnings)
4. #4 facebook.com (with warnings)
5. #9 microsoft.com (with warnings)
6. #11 youtube.com (with warnings)
7. #12 apple.com
8. #13 instagram.com (with warnings)
9. #16 x.com (via twitter.com) (with warnings)
10. #18 linkedin.com (with warnings)
11. #24 azure.microsoft.com (via azure.com) (with warnings)
12. #26 m365.cloud.microsoft (via office.com)
13. #27 outlook.live.com (via live.com) (with warnings)
14. #32 github.com (with warnings)
15. #33 wikipedia.org
16. #37 fastly.com (via fastly.net)
17. #39 whatsapp.com (via whatsapp.net) (with warnings)
18. #42 bing.com (with warnings)
19. #43 netflix.com (with warnings)
20. #44 triplinkintl.com
21. #48 gandi.net
22. #50 marketingplatform.google.com (via doubleclick.net)
23. #52 uk.pinterest.com (via pinterest.com) (with warnings)
24. #53 icloud.com (with warnings)
25. #55 wordpress.org (with warnings)
26. #56 teams.live.com (via skype.com) (with warnings)
27. #57 cloudflare.net
28. #60 digicert.com
29. #61 adobe.com
30. #63 tiktok.com (with warnings)
31. #67 domains.google (via googledomains.com)
32. #68 zoom.com (via zoom.us) (with warnings)
33. #69 uk.yahoo.com (via yahoo.com) (with warnings)
34. #71 endpoints.news
35. #75 roblox.com (with warnings)
36. #76 opera.com (with warnings)
37. #77 open.spotify.com (via spotify.com) (with warnings)
38. #80 baidu.com
39. #83 ya.ru (via yandex.net) (with warnings)
40. #84 nginx.org
41. #85 ntp.org
42. #86 msn.com (with warnings)
43. #87 qq.com (with warnings)
44. #90 vimeo.com (with warnings)
45. #91 primevideo.com (via amazonvideo.com) (with warnings)
46. #93 bunny.net (via b-cdn.net)
47. #94 blogger.com (via blogspot.com) (with warnings)
48. #95 mozilla.org
49. #96 f5.com (with warnings)
50. #98 telegram.org (via t.me)
51. #99 store.epicgames.com (via epicgames.com) (with warnings)
52. #101 wordpress.com (with warnings)
53. #103 reddit.com (with warnings)
54. #106 sentry.io (with warnings)
55. #107 letsencrypt.org (via lencr.org)
56. #109 ui.com (with warnings)
57. #110 european-union.europa.eu (via europa.eu) (with warnings)
58. #112 chatgpt.com (with warnings)
59. #116 bitly.com (via bit.ly) (with warnings)
60. #117 ipify.org
61. #119 nic.ru (with warnings)
62. #120 samsung.com (with warnings)
63. #122 intuit.com (with warnings)
64. #127 openai.com (with warnings)
65. #128 one.one.one.one (via cloudflare-dns.com) (with warnings)
66. #130 registrar-servers.com (with warnings)
67. #131 pages.github.com (via github.io)
68. #132 dropbox.com (with warnings)
69. #133 skybridge.click (with warnings)
70. #135 discord.com (via discord.gg) (with warnings)
71. #136 developer.adobe.com (via adobe.io)
72. #139 apache.org
73. #140 android.com (with warnings)
74. #144 vk.ru (with warnings)
75. #147 reg.ru (with warnings)
76. #150 t-online.de (with warnings)
77. #151 archive.org
78. #153 webex.com
79. #154 snapchat.com (with warnings)
80. #156 godaddy.com (with warnings)
81. #158 kaspersky.co.uk (via kaspersky.com) (with warnings)
82. #159 firebase.google.com (via crashlytics.com) (with warnings)
83. #160 tumblr.com (with warnings)

Overview

5/9

Gaining traction

Real support exists and adoption is growing.

How this rating is worked out5 of 9 points

Factor	Points	Why
Vendor support	1 / 3	1 vendor supporting, 1 partly or planned
Top-100 adoption	3 / 3	100% of measured sites
Spec maturity	1 / 3	Single-vendor spec

8 or more points is Established, 5 to 7 is Gaining traction, 2 to 4 is Speculative and under 2 is Stalled. A feature is also Stalled when more vendors have said no than yes. Read the spec.

Community insights

No community insights for this feature yet.

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