Perplexity
Comet
An agentic browser rather than a model: the assistant is built into the browsing surface itself.
Perplexity's approach is to make the browser itself agentic rather than bolt an agent onto one. The assistant lives in the browsing surface, with the page you are on as its working context.
Best for
Research and browsing tasks where context carries between pages.
Watch out
A product, not a platform. There is no way to embed it in something you are building.