Claude

Claude is the AI assistant and family of large language models built by Anthropic. People use it through the Claude apps on web, desktop and mobile, through Claude Code for software work, and through the Claude API, Amazon Bedrock, Google Cloud and Microsoft Foundry. When Claude searches the web, its answers cite the pages it used, which makes it one of the AI surfaces where brands can be cited or left out.

As of October 2026, Anthropic's model overview lists four current models. Claude Opus 5.5 (released September 22, 2026) is the recommended starting point for most work. Claude Fable 5.1 (September 1, 2026), the successor to the Fable 5 model Anthropic launched in June as its most capable generally available model, is aimed at demanding reasoning and long-horizon agent tasks. Claude Sonnet 5.5 (September 28, 2026) balances speed and intelligence, and Claude Haiku 5.5 (October 7, 2026) handles high-volume, latency-sensitive tasks. All four have a 1 million token context window, up to 128,000 output tokens, adaptive thinking, and a reliable knowledge cutoff of June 2026. A separate model, Claude Mythos 5.1, is limited to participants in Project Glasswing, Anthropic's defensive cybersecurity program.

The product has grown well beyond a chat window. Claude Code, Anthropic's agentic coding tool, runs in the terminal and IDE. Claude Cowork, generally available on desktop since April 2026, brought Claude Code's agent capabilities to everyday knowledge work, and since September 2026 its features have been rolling out to every conversation on Pro and Max plans. Claude can also operate a browser through Claude in Chrome and a desktop through computer use, and it connects to outside tools and data through the Model Context Protocol, the open standard Anthropic introduced in November 2024.

For AI search visibility, the key feature is web search, added to the Claude apps in March 2025. Claude decides per prompt whether to search; when it does, every answer includes citations, and when it answers from training data it cites nothing. TechCrunch reported at launch that Claude's web search appeared to use Brave Search, based on Anthropic's subprocessor list. That makes a page's ranking in Brave, not only Google, relevant to whether Claude finds it.

Anthropic runs three crawlers, described in its crawler help article: ClaudeBot collects content that may be used for training, Claude-SearchBot indexes pages to improve search results, and Claude-User fetches pages when a user's question needs them. Blocking ClaudeBot opts future content out of training; blocking Claude-SearchBot or Claude-User reduces your visibility in Claude's answers. Claude-User traffic is growing fast: Promptwatch's Claude citation crawler data shows it rising more than 100x between mid-December 2025 and mid-April 2026.

Anthropic does not publish Claude's consumer user numbers, so its reach is harder to size than ChatGPT's or Gemini's. Its weight is greatest among developers and professional users, where Claude Code is widely used and coding agents increasingly decide which tools and libraries to recommend.

To track Claude, separate two kinds of answers: those built from live web results, which cite sources and respond to content changes within days, and those built from training data, which reflect what the model learned before its cutoff. Keep Claude-SearchBot and Claude-User unblocked, check that key pages rank in Brave as well as Google, and monitor how Claude describes your brand alongside ChatGPT and Gemini.