By hand
Open a fresh session on each assistant, ask the question your buyer would ask, and write down who was named, in what order, and which pages were cited. Ten prompts on five assistants is fifty answers, an afternoon's work, and it shows you the shape of the problem better than any score. Keep the wording fixed so you can repeat it next month.
Free tools
Semrush's AI Search Visibility Checker takes a domain and reports mentions and citations across ChatGPT, Gemini, AI Mode and AI Overviews, with a score from 0 to 100 against others in your industry. No account is needed; the free tier allows three checks a day.
Ahrefs' Free AI Visibility Checker takes a brand name and checks ChatGPT, Gemini, Perplexity, Copilot, AI Overviews and AI Mode. It returns total mentions, mentions by platform, and the top five topics, cited domains and cited pages. No signup; the report is a one-time snapshot.
Both were read on 2026-10-21. Both answer "how often is my brand mentioned for prompts the tool chose". Neither lets you pick the prompts.
Seen42's free plan
The free plan runs one check of 10 prompts you choose, on ChatGPT and Gemini, and shows who was named and which sources were cited for each. It is the first step of the paid product, with the same methodology: mentions and citations counted separately, failed answers left out.
What a free check cannot tell you
One check is one day. Assistants vary from run to run, so a score of 40% today and 30% next week may be noise. A free check tells you where you stand; only repeated checks of the same prompts tell you whether anything changed.
