LLM Visibility Tools: What They Measure, and What They Can Only Estimate

Most LLM visibility tools run a set of prompts through AI assistants and search features on a schedule, then record whether your brand or pages are mentioned or cited and how often. The resulting share-of-voice or visibility score is a sample, not a census: it depends entirely on which prompts were chosen, which models were queried, from where, and how many times.

That does not make the tools useless. It means the number is only as good as the prompt set, and two tools can report very different scores for the same brand because they ask different questions.

Ask for the methodology in writing: how prompts are selected, whether you can supply your own, which platforms and model versions are covered, what locations and languages, how often each prompt is repeated and how answer variability is handled. Ask to see raw answers behind any score.

Check that the tool separates brand mentions from linked citations, and that it lets you export data. A dashboard you cannot audit is hard to defend when a number moves.

Your own data shows what actually reached you. Analytics can capture visits referred by AI assistants, though many arrive without a referrer. Server logs show which AI crawlers fetched which pages; OpenAI and Perplexity document their crawler user agents. Google includes AI features in Search Console performance data, and Bing Webmaster Tools reports AI performance for Copilot and Bing.

Read these together. A tool may show rising mentions while referrals stay flat, which suggests visibility without clicks; logs may show a crawler never reaching the pages you most want cited.

Be cautious about promised uplifts. The academic research behind GEO measured how much of an answer a source earned once it was already retrieved, and a later benchmark found most tested optimisation tricks produced no significant gain. Visibility depends on being crawlable, indexed and genuinely useful first.

Use tools to find prompts where competitors appear and you do not, then fix the underlying pages and third-party presence. Track the direction over months rather than reacting to weekly swings.