Earlier this week, Anthropic rolled out a web search feature for its AI-powered chatbot platform, Claude, bringing the bot in line with many of its rivals. It wasnt immediately clear which search index might be powering the feature one possibility was that Anthropic had developed its own. But evidence suggests its Brave Search, the search engine maintained by browser developer Brave. As spotted by software engineer Antonio Zugaldia on Friday, Anthropic added Brave Search to the subprocessor list in its documentation this week the list of Anthropic partners who process Claude data. British programmer Simon Willison reports that at least one search in Claude and Brave returned identical citations. Willison also found that Claudes web search function contains a parameter called BraveSearchParams.Weve reached out to Anthropic and will update this post if we hear back.Brave underpins at least one other chatbots search functionality: Mistrals chatbot platform Le Chat. In February, Brave and Mistral announced that Le Chat would use Braves search API for live web results.Some AI companies keep info about their search index partnerships close to the chest, possibly for competitive reasons. OpenAI has a partnership with Bing but uses other undisclosed sources to power the search experience in ChatGPT as well.