Allow AI search/retrieval bots in robots.txt
Pages must be fetchable by AI search and agent bots (OAI-SearchBot, PerplexityBot, Claude-SearchBot, Claude-User) to be cited live. Blocking ChatGPT-User or Perplexity-User in robots.txt may be ignored by design, and blocking training-only bots (GPTBot, Google-Extended) matters much less.
Best study is at least large-n observational or controlled, with some replication. Outcome data is still mostly correlational.
Outcome studies are still mostly correlational unless the write-up says otherwise.
How to fix
Let AI search and agent bots in through robots.txt so they can read your page live. This removes a blocker; it doesn't promise a mention.
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Open
https://yoursite.com/robots.txt. It should load (200) or not exist (404). A server error (5xx) makes crawlers treat your whole site as off-limits, so fix that first with your host. -
Look for rules that block
OAI-SearchBot,PerplexityBot,Claude-SearchBot,Claude-User,GooglebotorBingbot, and forUser-agent: *withDisallow: /, which blocks every bot without its own group. -
Give those bots their own group that allows the page. A bot follows only the group that names it, so repeat any private paths:
User-agent: OAI-SearchBot User-agent: PerplexityBot User-agent: Claude-SearchBot User-agent: Claude-User User-agent: Googlebot User-agent: Bingbot Allow: / Disallow: /admin/ User-agent: * Disallow: /admin/ -
Remove any
DisallowforChatGPT-UserorPerplexity-User. OpenAI says robots.txt rules "may not apply" to ChatGPT-User, and Perplexity says Perplexity-User "generally ignores robots.txt rules". To block them, use your firewall. -
If the check says your site turned it away (403), see "Firewall and CDN rules" below: robots.txt isn't the cause.
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Save and deploy. OpenAI and Perplexity say changes can take up to about 24 hours to reach them.
How to check it worked: run the free check again. The "AI agents are allowed in" row should pass: "Your robots.txt lets every AI search and agent bot we track open this page."
Firewall and CDN rules
robots.txt only asks; your firewall, CDN (the network that serves your site) or bot filter decides who gets in. Let AI search and agent bots through, and allow them by the vendors' published IP addresses or your provider's verified-bot setting, not by name alone.
- Find the rule. In your firewall or CDN log, filter for the time of the check and the bots named in the row (OAI-SearchBot, PerplexityBot, Claude-SearchBot, Claude-User, Google-Agent). Note which rule fired: an AI bot setting, bot protection, a rate limit, or a country or user-agent block.
- Cloudflare. In Security Settings, open the AI bot policies and set Search and Agent to Allow (Training is your call, see next section). Since September 15, 2026, Cloudflare offers new domains recommended AI settings. For sites with ads, that means search crawlers allowed, AI training disallowed, and AI agents blocked on pages that carry ads. If you added your site after that date, check these settings even if you never changed them. To let verified bots past your custom rules, add a WAF rule on
cf.client.bot. - Vercel. Open Firewall, then Rules. If the AI Bots Managed Ruleset (Allow by default) says Deny, set it to Log or Allow. If Bot Protection is on Challenge, add a custom Bypass rule for the AI bots you want.
- Akamai. In Bot Management, set the AI bot categories you want to Allow or Monitor, not Deny.
- Other firewalls. Allow each bot only when its IP address is on the vendor's published list. OpenAI, Perplexity and Google each publish one.
- Check for HTTP 402. It means pay per crawl is on: bots that don't pay get a payment request instead of the page. Keep it only if that's your plan.
How to check it worked: run the free check again. The "Your firewall passed our AI-crawler test" row should pass: "Our AI-crawler test got through: your page loaded when we visited as each of the {n} AI agents we test." Our test runs from our own servers, so if you verify AI crawlers by IP address, a Watch here is expected. If you don't, check your firewall rules. This row never fails: the worst it shows is Watch.
Training bots are a policy choice
Decide whether AI companies may train on your pages. Most use separate bots for training and search, so you can block training and stay findable. The exception is Google-Extended, which also decides whether Gemini can use your pages in its answers. The free check reports your choice but doesn't grade it.
| Company | Search or agent bot (keep allowed to be found) | Training bot or token (your choice) | What the vendor says |
|---|---|---|---|
| OpenAI | OAI-SearchBot, ChatGPT-User | GPTBot | Each setting is independent: allow OAI-SearchBot to appear in ChatGPT search, and disallow GPTBot to keep your content out of training. |
| Anthropic | Claude-SearchBot, Claude-User | ClaudeBot | Blocking ClaudeBot signals your future content should be left out of training. Blocking Claude-SearchBot or Claude-User may reduce your visibility in Claude's answers. |
Googlebot | Google-Extended (a robots.txt token, not a separate crawler) | Google-Extended controls training of future Gemini models and grounding (using your pages in answers) in Gemini Apps and Vertex AI. It doesn't affect inclusion or ranking in Google Search, so it doesn't control AI Overviews. | |
| Apple | Applebot | Applebot-Extended | Disallowing Applebot-Extended opts out of training Apple's generative models. Applebot can still crawl your pages. |
| Common Crawl | none | CCBot | An open dataset. Block with User-agent: CCBot / Disallow: /. |
| Perplexity | PerplexityBot, Perplexity-User | none | PerplexityBot is not used to crawl content for AI foundation models. |
To change your policy:
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Choose: training allowed (the default with no rule) or blocked.
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To block training, put the training bots in one group:
User-agent: GPTBot User-agent: ClaudeBot User-agent: Google-Extended User-agent: Applebot-Extended User-agent: CCBot Disallow: / -
Keep search bots (
OAI-SearchBot,Claude-SearchBot,PerplexityBot,Googlebot,Bingbot) out of that group, or the "AI agents are allowed in" row will fail. -
On Cloudflare, check its Training setting too. It can block training bots at the edge and write these robots.txt lines for you.
How to check it worked: run the free check again. The "AI training bots" row should read "You block {bots} from training on your pages.", and "AI agents are allowed in" should still pass.
What the free check looks for
- Fetch /robots.txt and parse the rules for each known AI user-agent (search, agent fetch, training).
- A Disallow on the audited path for OAI-SearchBot, Claude-SearchBot, Claude-User, PerplexityBot, Googlebot or Bingbot fails the gate.
- A Disallow for ChatGPT-User or Perplexity-User only warns: OpenAI says robots.txt "may not apply" to ChatGPT-User and that it doesn't decide Search inclusion (use OAI-SearchBot), and Perplexity says Perplexity-User "generally ignores" robots.txt. Block or allow those at your firewall instead.
- Training-bot blocks are informational. Also fetch the page as AI crawler user-agents to catch CDN/WAF blocks that robots.txt can't show.
- If you allowlist AI bots at the firewall, verify them against each vendor's published IP list. Allowing by user-agent name alone lets fakes in.
Caveats
- — Crawl Readiness (Oct 2026, vendor, open data): 14.2% of responding Tranco top-1,000 sites (78 of 549) refuse at least one AI crawler at the server while robots.txt allows it. robots.txt is only one layer.
- — robots.txt blocks are not airtight: Toronto (2610.15033) found 7.1% of pages ChatGPT cited disallowed OAI-SearchBot. Engines can learn a URL from other sources. Treat robots.txt as a request, and firewall rules as enforcement.
- — Correlational studies dominate this field. AI citations churn: a small 15-prompt preprint (arXiv 2609.22655; the author sells AI-visibility tooling) saw each engine's cited URL set change by about 67% on average from one day to the next, with under 1% URL overlap across engines. Toronto (2610.15033) found only about 40% of the within-site pattern of ChatGPT citations still held two weeks later, and 14% after ten weeks. Re-verify yearly.
- — Included in the free page check.
Studies and docs
2026
OAI-SearchBot governs ChatGPT search inclusion; GPTBot is for training. For ChatGPT-User, robots.txt rules "may not apply" because fetches are user-initiated, and it "is not used to determine whether content may appear in Search".
2025
Top-50 news sites, citations across ChatGPT, Gemini, AI Overviews and AI Mode: 88.2% of sites blocking GPTBot still appeared — but so did 82.4% blocking OAI-SearchBot and 70.6% blocking ChatGPT-User. Shows blocks are leaky (news sites get cited via syndication and other routes), not that only retrieval-bot blocks matter. Small sample; the page's own Google-Extended figures disagree (92.3% in text, 88.2% in table).
2025
Google-Extended controls whether content is used to train Gemini models and to ground answers in Gemini Apps and Vertex AI. It does not affect a site's inclusion or ranking in Google Search, so it doesn't control AI Overviews.
2026
PerplexityBot surfaces sites in Perplexity search results and is controlled through robots.txt. Perplexity-User fetches on a user's request and "generally ignores robots.txt rules". Published IP lists are provided for WAF allowlisting.
2026
78 of 549 responding sites (14.2%) refuse at least one of OAI-SearchBot, PerplexityBot, GPTBot or ClaudeBot at the server while robots.txt allows it (11.7% excluding 429-only). Probes used user-agent strings, not vendor IPs. Vendor research with open data.
2022
The robots.txt standard the free check follows: most specific user-agent group wins and same-agent groups merge; longest matching path wins, Allow on a tie; * and $ wildcards; 4xx = no restrictions; 5xx or network error = assume complete disallow; parse at least 500 KiB.
2026
Google treats 4xx except 429 as no robots.txt; on 5xx it stops crawling for 12 hours, then uses the last cached copy for up to 30 days; content past 500 KiB is ignored.
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