Claude
Claude is the family of large language models built by Anthropic, available as a chat app, a browser and desktop assistant, and an API that other software builds on. Ask it a question in plain language and it answers in full sentences, sometimes naming specific products, companies or sources along the way. For GEO, that matters because Claude is one of several assistants deciding which brands get named in an answer and which don't — a selection process that runs on different signals than classic search rankings.
Why Claude matters for your visibility
People increasingly ask an assistant instead of typing a query into a search box: "Which tax advisor suits a small trade business?" or "Recommend a family hotel in the Allgäu." Claude answers with a short, specific list rather than ten blue links. Get named there and you reach someone before they ever open a search results page; get left out and you're simply not part of the conversation. This isn't a niche channel to ignore — competing assistants have scaled fast enough that AI answers are now a mainstream on-ramp: Gemini alone passed 1 billion monthly users in August 2026, and Google's AI Overviews reach over 2 billion monthly users across 200-plus countries. Claude sits alongside them as one more surface deciding whether your brand gets mentioned at all.
How Claude works
Claude is a transformer-based language model trained to predict, and generate, plausible text one piece at a time, informed by patterns learned from huge volumes of training data. Some of what it "knows" is baked into the model at training time; in products where it's connected to search or to documents, it can also pull in current information at answer time. Anthropic ships Claude through a chat interface and through an API that other companies build agents and products on top of. Unlike a search engine, Claude has no fixed index of web pages it ranks — it composes an answer from what it learned plus whatever it looked up. That's why how clearly and consistently your business describes itself in public, machine-readable text shapes whether Claude can describe you accurately at all.
Common mistakes
The most common mistake is treating Claude like a search engine and stuffing pages with keywords — language models weigh relationships and context, not keyword density. A second is trusting anything Claude says without checking it: models can state confident, plausible-sounding things that are simply wrong, a failure mode called hallucination, and independent testing has found AI tools misidentify basic facts about sources at a troublingly high rate. Third, teams chase markup that doesn't do what they think it does: Google has stated plainly that no special schema, llms.txt file, or AI-specific markup is required for its AI features, and one large-scale check found that roughly 97% of sites that published an llms.txt file saw no measurable referral traffic from it. Fourth, people over-invest in links and under-invest in being talked about: independent analysis found that how often a brand is mentioned across the web correlates with AI citation rate roughly three times more strongly than backlinks do. Finally, don't judge from one test — the same question can get a different answer depending on phrasing, so track results over time rather than off a single query.
Relation to Generative Engine Optimization
Claude is one of the destinations GEO work is aimed at, alongside ChatGPT, Gemini and Perplexity. The term itself comes from a specific place: the 2024 paper "GEO: Generative Engine Optimization" (Aggarwal, Murahari, Narasimhan, Deshpande, Rajpurohit and Kalyan), presented at ACM SIGKDD. Practically, this means tracking whether and how Claude mentions your brand, in what context, and with what tone — the basis of metrics like mention rate and visibility score. Being cited by an assistant isn't the same competition as ranking in Google: research on ChatGPT citations found only 6–8% overlap with Google's top-10 results for the same queries, and around 80% of cited URLs didn't rank in Google's top 100 at all. That's a different selection process, and it rewards the same evidence GEO points to generally: clear, specific descriptions of what you do, verifiable facts, real third-party mentions, and consistent details wherever your business appears online.
Example
A customer planning a move asks Claude: "Which moving companies in Leipzig work with fixed prices?" Instead of a page of links, she gets three names, each with a line on what sets it apart. A moving company whose site spells out prices, process and service area in plain text gets named. A competitor with a vague, marketing-heavy homepage and no concrete details doesn't come up, even with decent reviews elsewhere. She calls the companies she was given. The one left out never even learns the job existed.
Common questions
Is Claude the same as ChatGPT?
No. Both are AI assistants built on large language models, but from different companies — Claude from Anthropic, ChatGPT from OpenAI (which reported 900 million weekly active users in early 2026). They're trained differently and can answer the same question differently, so check your visibility in each one separately rather than assuming results transfer.
Can I influence what Claude says about my brand?
Not directly, and not through special files or markup — there's no submission process and no llms.txt trick that reliably changes what Claude says. What actually correlates with getting cited is being described clearly and consistently across your own site and mentioned genuinely by other sources around the web; that's the signal language models pick up on.