Large language models are bounded by their training data. Anything that happened after the cutoff, anything niche enough to be underrepresented, anything changing in real time, none of it is reachable by the model alone. Ask a model about something that didn't exist when the model was trained, and the answer is either out of date or fabricated.
The capability to search the web, read the results contents, and bring the information cleanly into the model's context, isn't built into the models themselves. It has to be assembled. And assembling it well is harder than it looks. The developer doesn't just need data; they need data shaped for a model's context, full content rather than summary snippets, ranked for relevance so token budgets aren't wasted on noise, and reliable enough to be worth integrating against. To get that depth, developers building AI products at the API level have typically had to balance a search service, a scraping service, and a reranking endpoint, each with its own cost model, failure mode, and integration surface.
Sonar is that capability, assembled. One pipeline, one call, with results shaped for a model's context.