In AI visibility, sentiment is how favorably an answer frames a brand when it mentions it — recommended, neutral, caveated, or warned against.
A mention is not automatically a win. "X is the market leader, though users report billing issues" and "X is the best choice for most teams" are both mentions of X with very different value. Sentiment analysis classifies that framing at scale.
Sentiment usually traces to sources. Models echo the tone of what they read — persistent caveats in AI answers tend to have a findable origin in reviews, forums, or comparison articles.