Why AI crawler access matters
When an AI assistant answers a buying question — 'best family dentist in Denver', 'top invoicing tool for freelancers' — it draws on two kinds of knowledge: what the underlying model learned during training, and what a retrieval system fetched from the live web moments before answering. Both paths start with crawlers. If the bots that collect training data and the bots that fetch pages for retrieval cannot read your site, you are handing the entire AI answer to competitors whose sites they can read.
The frustrating part is that most AI-crawler blocks are accidents. In 2023–2024, many sites (or their CDN providers and security plugins) added blanket rules blocking bots like GPTBot out of caution. Those rules are still sitting in robots.txt files today, quietly excluding businesses from AI answers while their owners wonder why they never get recommended. A one-minute check catches this class of problem before you spend a cent on content.
The crawlers that matter in 2026
OpenAI operates GPTBot (training data collection), OAI-SearchBot (search index for ChatGPT's browsing) and ChatGPT-User (real-time fetches when a user's chat triggers a page visit). Anthropic operates ClaudeBot and anthropic-ai. Perplexity uses PerplexityBot. Google's crawling for AI features is tied to Googlebot and Google-Extended — blocking Google-Extended opts your content out of Gemini training while keeping normal search. Others worth knowing: Amazonbot, Applebot-Extended, Bytespider (ByteDance), CCBot (Common Crawl, whose corpus many models train on), and Meta-ExternalAgent.
Each responds to standard robots.txt directives under its own user-agent token. This checker requests your robots.txt and evaluates the allow/disallow rules for each of these tokens exactly the way the crawlers themselves do, including wildcard user-agent blocks that catch AI bots as collateral damage.
How to read your results
Allowed means the crawler may fetch your pages; it does not guarantee it will, or that your content will appear in any AI system — it only removes a hard blocker. Blocked means the crawler is excluded by a matching disallow rule. Pay special attention when everything is blocked by a 'User-agent: *' catch-all: that usually signals a staging configuration or an overzealous security preset rather than a deliberate policy.
A deliberate mixed policy is perfectly legitimate. Some publishers allow retrieval bots (which can cite and link to them) while blocking training bots. For a business that wants to be recommended by AI, though, the pragmatic default in 2026 is to allow the major AI crawlers: the upside is inclusion in answers; the downside for a typical business site is negligible.
Fixing a block
robots.txt lives at the root of your domain and is plain text. To unblock a specific crawler, remove its disallow rule or add an explicit allow section, for example: 'User-agent: GPTBot' followed by 'Allow: /'. If your file has a blanket 'User-agent: *' with 'Disallow: /', scope it down to the paths you actually need private. Remember that CDN-level bot protection (Cloudflare, Akamai) and security plugins can block crawlers even when robots.txt allows them — if this checker says you are open but AI systems still cannot summarize your site, look at your WAF settings next.
After fixing, re-run the check to confirm, then give the systems time: retrieval bots pick up changes within days, while training corpora refresh on much longer cycles. Crawler access is step zero of AI visibility — once it is green, the question becomes whether AI actually recommends you, which is what our free scan measures.