Overview
A swarm uses more tokens than a normal single-agent task and can take much longer. In the site-building case, the swarm ran for hours and remained only partway through its planned stages. This makes swarms appropriate for substantial work, not for every request.
Multi-agent work can also produce a large amount of intermediate activity. Progress indicators, per-agent inspection, and stop controls are therefore part of the operational design.
The central mistake is to equate more agents with a better result. Use swarms for massive tasks that require substantial work. Use a single focused agent when it can complete the job more efficiently.