ChatGPT vs Claude for brand visibility

The same idea, documented differently

OpenAI and Anthropic have arrived at the same architecture: one crawler per job, so that a site owner can say yes to one use of their content and no to another. Both publish the list. That is genuinely useful and it was not the default a few years ago.

Where they differ is in what the documentation commits to. OpenAI writes down consequences and timings. Anthropic writes down a principle and a warning. Both approaches leave you able to act; they leave you able to verify to different degrees.

OpenAI's four agents

The OpenAI crawler documentation names four.

OAI-SearchBot is "used to surface websites in search results in ChatGPT's search features",[^oai-searchbot-purpose] and the consequence of opting out is stated plainly: those sites "will not be shown in ChatGPT search answers."[^oai-searchbot-optout]

GPTBot is described as "used to make our generative AI foundation models more useful and safe",[^oai-gptbot-purpose] with disallowing it indicating that content should not be used in training those models.

OAI-AdsBot is "used to validate the safety of web pages submitted as ads on ChatGPT", and OpenAI states that the data it collects is not used to train foundation models.[^oai-adsbot]

ChatGPT-User covers certain user actions in ChatGPT and Custom GPTs, with the caveat that "because these actions are initiated by a user, robots.txt rules may not apply."[^oai-chatgpt-user-robots]

Around all four sits an operational layer: a separate IP list per agent[^oai-ip-ranges] and a stated propagation time of roughly 24 hours for a robots.txt change to be picked up.[^oai-robots-lag]

Anthropic's three agents

Anthropic's crawler support article names three.

ClaudeBot "helps enhance the utility and safety of our generative AI models by collecting web content that could potentially contribute to their training."[^anthropic-claudebot-purpose] That is the training crawler, and the phrasing is careful: content that could potentially contribute, rather than content that will.

Claude-User "supports Claude AI users. When individuals ask questions to Claude, it may access websites using a Claude-User agent."[^anthropic-claude-user] This is the user-initiated fetch, and it is where the two vendors' documentation most clearly parts company: Anthropic places it under the same robots.txt commitment as everything else, while OpenAI's equivalent carries an explicit hedge.

Claude-SearchBot "navigates the web to improve search result quality for users", analysing online content to enhance the relevance and accuracy of search responses.[^anthropic-searchbot]

The commitment underneath them is a single sentence: Anthropic says it will "respect 'do not crawl' signals by honoring industry standard directives in robots.txt", and gives the User-agent: ClaudeBot / Disallow: / form as the example.[^anthropic-robots-commitment] It also supports the non-standard Crawl-delay extension,[^anthropic-crawl-delay] which is a rate control OpenAI does not document.

And it adds a warning that most vendors leave implicit: alternate methods such as blocking IP addresses "may not work correctly or persistently guarantee an opt-out."[^anthropic-ip-blocking-warning]

The asymmetry that actually matters

Read the two documents together and one gap stands out.

OpenAI tells you what you lose. Block OAI-SearchBot and your site will not appear in ChatGPT search answers — a sentence you can quote to a security team that wants to block everything, and a sentence you can plan around.

Anthropic tells you what each agent does but not what blocking each one costs. Claude-SearchBot exists "to improve search result quality"; the article does not say that blocking it removes a site from anything. That is a documentation gap rather than a behavioural claim, and this page will not fill it with a guess. If you are deciding whether to block Claude-SearchBot, you are deciding without a published consequence, and that is worth knowing before you make the decision rather than after.

The reverse asymmetry is on IP handling. OpenAI's per-agent IP lists make verification straightforward: you can check whether a request claiming to be GPTBot came from an OpenAI address. Anthropic offers no equivalent verification list on the crawler page and actively discourages the IP-based approach to blocking. If your operations team's instinct is to solve crawler questions at the firewall, one vendor supports that instinct partially and the other tells you it will not hold.

What both of them do the same way

Both separate training from everything else, and both make that separation addressable by name. This is the single most useful fact on the page, and the most commonly discarded.

A site that adds User-agent: * / Disallow: / to protect against AI training has also blocked the agents that make it findable. On the OpenAI side that has a documented cost. On the Anthropic side it removes the search-quality crawler along with the training one. Neither vendor requires that trade, and neither benefits from it.

The correct move is boring: name the agents individually, decide training and findability separately, and write the file so that a future reader can see which decision was which.

Both vendors also attach citation behaviour to their developer search products. OpenAI's web search guide requires that "inline citations must be made clearly visible and clickable in your user interface."[^oai-citation-display] Anthropic states that citations are always enabled for web search, each carrying the source URL, the title and up to 150 characters of the cited content.[^anthropic-citations-always] Different mechanisms, same direction of travel: products built on either vendor's search are expected to show where the material came from.

A robots.txt that expresses the actual decision

If the decision is "be findable, do not be training data", the tokens involved are OAI-SearchBot and Claude-SearchBot on the allow side, GPTBot and ClaudeBot on the disallow side, with ChatGPT-User and Claude-User handled as the user-initiated cases they are and OAI-AdsBot decided only if you run ads on ChatGPT.

Two operational notes. OpenAI's roughly 24-hour propagation means a change is not wrong just because it has not taken effect within the hour.[^oai-robots-lag] Anthropic publishes no equivalent window,[^anthropic-no-propagation-window] so the only honest procedure there is a repeating check rather than a deadline.

The user-initiated fetch is the hardest case on both sides

Of the seven agents across the two vendors, the two that cause the most confusion are the ones triggered by a person: ChatGPT-User and Claude-User.

The confusion is reasonable, because the situation is genuinely ambiguous. A robots.txt file expresses a site's policy toward automated crawling. When a human being asks an assistant to read a specific page, the request is not really automated crawling — it is closer to that person opening the page in a browser, with software in between. Both vendors have had to take a position on that, and they have taken subtly different ones.

OpenAI's position is a hedge: because the actions are initiated by a user, robots.txt rules may not apply. The word doing the work is "may". It tells you the rules are not guaranteed to be honoured, and it does not tell you when they are.

Anthropic's crawler article takes a simpler line, listing Claude-User among the agents covered by its general commitment to honour industry-standard robots.txt directives, without carving out an exception for user-initiated requests.

For a site owner, the practical guidance is the same either way, and it is uncomfortable: a robots.txt disallow is a policy signal, not an access control. If a page must not be readable by a third party under any circumstances, the mechanism for that is authentication, not a directive in a text file that some agents describe themselves as possibly ignoring. Conversely, if your goal is visibility rather than protection, this whole category of agent is on your side — a person asked for your page by name, which is the closest thing to intent that exists in this stack.

Both vendors deserve some credit for documenting the ambiguity rather than leaving site owners to discover it in their logs. Neither has resolved it, and neither is likely to, because the underlying question is a policy question rather than a technical one.

What neither vendor publishes

Neither document explains how a brand comes to be named in an answer. Both explain retrieval permissions. Neither explains selection.

That boundary is worth being pedantic about, because the gap between "my pages are crawlable" and "my brand is mentioned" is where most of the money in this category is spent. The first is a documented, verifiable, one-afternoon fix. The second is unpublished on both platforms and observable only by sampling real prompts repeatedly and recording the date, the prompt set and the sampling depth alongside every number.

Related comparisons

For the case where one platform gates answers behind its own crawler and the other inherits eligibility from ordinary search, see Google AI Overviews versus ChatGPT search. For a platform whose user-initiated fetcher explicitly ignores robots.txt, see ChatGPT search versus Perplexity. And for what each vendor hands a developer once a source has been used, see Claude versus Gemini on citations.

The limit of this page

Everything above is drawn from OpenAI's crawler and web search documentation and Anthropic's crawler support article and web search tool documentation, all fetched on 3 September 2026. Both vendors revise these pages without notice, which is why every claim carries its retrieval date and why this page is reviewed quarterly rather than treated as settled.

Where a vendor has not published something — what blocking Claude-SearchBot costs, how long an Anthropic robots.txt change takes, whether OpenAI honours Crawl-delay — this page says so instead of filling the gap. A comparison that guesses at the missing cells reads better and is worth less.

[^oai-searchbot-purpose]: OpenAI crawler documentation, retrieved 2026-09-03. [^anthropic-claudebot-purpose]: Anthropic crawler support article, retrieved 2026-09-03.