Are fixed prompts enough to measure AI search visibility?

Many brands measure AI search visibility by running a predefined list of prompts and counting how frequently they appear in the answers.

For example, a SaaS company might track prompts such as "best CRM software," "top CRM platforms," and "CRM tools for sales teams."

These prompts provide a useful starting point, but buyers often ask more specific questions based on their requirements.

Someone might need a CRM for a 10-person team, while another is looking for software that integrates with Salesforce or supports complex enterprise workflows. Each scenario can produce a different set of recommendations.

Tracking prompts across buyer segments, use cases, and purchasing stages can reveal where a brand appears consistently and which competitors are recommended for particular requirements.

How are you selecting the prompts used to measure your brand's AI visibility? Are they based on actual buyer questions or a fixed keyword list?