Who blocks AI · #673 in the Majestic Million

robots.txt · checked 9 Nov 2026

Does cell.com block AI crawlers?

Yes. cell.com’s robots.txt blocks 11 of the 19 AI crawlers we track, including GPTBot, ClaudeBot, Google-Extended and 8 more. Search engines such as Googlebot and Bingbot may crawl it.

GPTBotBlocked OAI-SearchBotAllowed ClaudeBotBlocked PerplexityBotBlocked Google-ExtendedBlocked CCBotBlocked

robots.txt: www.cell.com/robots.txt · 116 lines
llms.txt: none
Checked: 9 November 2026, as canaicrawl. We check again every week.

Every bot, and the line that decides

Search engines

Bot	Operator	robots.txt	Deciding line
`Googlebot`	Google	Allowed	no rule matches the home page
`Bingbot`	Microsoft	Allowed	no rule matches the home page
`DuckDuckBot`	DuckDuckGo	Allowed	no rule matches the home page
`Applebot`	Apple	Allowed	no rule matches the home page
`PetalBot`	Huawei	Allowed	no rule matches the home page
`YandexBot`	Yandex	Allowed	no rule matches the home page
`Baiduspider`	Baidu	Allowed	no rule matches the home page

AI search

Bot	Operator	robots.txt	Deciding line
`OAI-SearchBot`	OpenAI	Allowed	no rule matches the home page
`PerplexityBot`	Perplexity	Blocked	line 57 · `Disallow: /` under `User-agent: PerplexityBot`
`Claude-SearchBot`	Anthropic	Allowed	no rule matches the home page
`DuckAssistBot`	DuckDuckGo	Allowed	no rule matches the home page
`Amazonbot`	Amazon	Blocked	line 65 · `Disallow: /` under `User-agent: Amazonbot`
`YouBot`	You.com	Blocked	line 113 · `Disallow: /` under `User-agent: YouBot`

AI training

Bot	Operator	robots.txt	Deciding line
`GPTBot`	OpenAI	Blocked	line 41 · `Disallow: /` under `User-agent: GPTBot`
`ClaudeBot`	Anthropic	Blocked	line 73 · `Disallow: /` under `User-agent: ClaudeBot`
`Google-Extended`	Google	Blocked	line 53 · `Disallow: /` under `User-agent: Google-Extended`
`CCBot`	Common Crawl	Blocked	line 49 · `Disallow: /` under `User-agent: CCBot`
`Applebot-Extended`	Apple	Allowed	no rule matches the home page
`GoogleOther`	Google	Allowed	no rule matches the home page
`Meta-ExternalAgent`	Meta	Blocked	line 97 · `Disallow: /` under `User-agent: meta-externalagent`
`Bytespider`	ByteDance	Blocked	line 77 · `Disallow: /` under `User-agent: Bytespider`

User-triggered fetchers

Bot	Operator	robots.txt	Deciding line
`ChatGPT-User`	OpenAI	Blocked	line 45 · `Disallow: /` under `User-agent: ChatGPT-User`
`Claude-User`	Anthropic	Allowed	no rule matches the home page
`Perplexity-User`	Perplexity	Allowed	no rule matches the home page
`MistralAI-User`	Mistral	Blocked	line 101 · `Disallow: /` under `User-agent: MistralAI-User`
`Meta-ExternalFetcher`	Meta	Allowed	no rule matches the home page

SEO tools

Bot	Operator	robots.txt	Deciding line
`AhrefsBot`	Ahrefs	Allowed	no rule matches the home page
`SemrushBot`	Semrush	Allowed	no rule matches the home page
`MJ12bot`	Majestic	Allowed	no rule matches the home page
`DotBot`	Moz	Allowed	no rule matches the home page

View www.cell.com/robots.txt · 116 lines

1Sitemap: https://www.cell.com/sitemap-index-1.txt

2Sitemap: https://www.cell.com/custom_pages.gz

4User-agent: *

5Disallow: /action

6Disallow: /help

7Disallow: /search

8Disallow: /feedback

9Disallow: /rss

10Disallow: /action/clickThrough

11Disallow: /action/showLogin

12Disallow: /page/account-confirmation-thanks

13Disallow: /media

14Disallow: /medical-research

15Disallow: /servlet/linkout

16Disallow: /na101/

17Disallow: /na101v1/

18Disallow: /na102/

19Disallow: /doi/mlt/

20Disallow: /cms/attachment/92c526c4-ef1f-4065-b12b-ca4ae0f3e84f/gr1*

21Disallow: /personalize/addFavoritePublication

22Disallow: /pb/widgets/*

23Disallow: /authored-by/

24Allow: /action/showJournal

25Allow: /action/showXml

26Allow: /series

27Allow: /isbn

28Allow: /doi/book

29Allow: /.well-known/*

30Crawl-delay: 1

32User-agent: Twitterbot

33Allow: /

34Crawl-delay: 1

36User-agent: LinkedInBot

37Allow: /

38Crawl-delay: 1

40User-agent: GPTBot

41Disallow: /

42Crawl-delay: 1

44User-agent: ChatGPT-User

45Disallow: /

46Crawl-delay: 1

48User-agent: CCBot

49Disallow: /

50Crawl-delay: 1

52User-agent: Google-Extended

53Disallow: /

54Crawl-delay: 1

56User-agent: PerplexityBot

57Disallow: /

58Crawl-delay: 1

60User-agent: AI2Bot

61Disallow: /

62Crawl-delay: 1

64User-agent: Amazonbot

65Disallow: /

66Crawl-delay: 1

68User-agent: anthropic-ai

69Disallow: /

70Crawl-delay: 1

72User-agent: ClaudeBot

73Disallow: /

74Crawl-delay: 1

76User-agent: Bytespider

77Disallow: /

78Crawl-delay: 1

80User-agent: cohere-training-data-crawler

81Disallow: /

82Crawl-delay: 1

84User-agent: cohere-ai

85Disallow: /

86Crawl-delay: 1

88User-agent: Diffbot

89Disallow: /

90Crawl-delay: 1

92User-agent: iAskBot/1.0

93Disallow: /

94Crawl-delay: 1

96User-agent: meta-externalagent

97Disallow: /

98Crawl-delay: 1

100User-agent: MistralAI-User

101Disallow: /

102Crawl-delay: 1

103

104User-agent: omgili

105Disallow: /

106Crawl-delay: 1

107

108User-agent: TimpiBot

109Disallow: /

110Crawl-delay: 1

111

112User-agent: YouBot

113Disallow: /

114Crawl-delay: 1

115

116

What do the bots actually get?

This page reads robots.txt, which states what cell.com asks of crawlers. A firewall or CDN can still refuse a bot that robots.txt allows. The live check requests the page as each bot and shows the status it gets.

Run a live check on cell.com Test a path in the robots.txt tester

History

19 October 2026: first checked.

Questions

Does cell.com block GPTBot?

Yes. cell.com’s robots.txt disallows GPTBot from the whole site (line 41: Disallow: /). GPTBot is OpenAI’s crawler for training data; blocking it doesn’t affect ChatGPT search, which uses OAI-SearchBot. Checked 9 November 2026.

Does cell.com block ClaudeBot?

Yes. cell.com’s robots.txt disallows ClaudeBot from the whole site (line 73: Disallow: /). ClaudeBot is Anthropic’s crawler for training data. Checked 9 November 2026.

Does cell.com block Google-Extended?

Yes. cell.com’s robots.txt disallows Google-Extended from the whole site (line 53: Disallow: /). Google-Extended is the token that controls whether Google may use pages for Gemini training and grounding; it doesn’t affect Google Search. Checked 9 November 2026.

Does cell.com block PerplexityBot?

Yes. cell.com’s robots.txt disallows PerplexityBot from the whole site (line 57: Disallow: /). PerplexityBot is the crawler that indexes pages for Perplexity’s answers. Checked 9 November 2026.

Can ChatGPT search find cell.com?

Yes. cell.com’s robots.txt lets OAI-SearchBot crawl the site. OAI-SearchBot is the crawler behind ChatGPT search; blocking it keeps the site out of ChatGPT’s search answers. Checked 9 November 2026.