I only use parallel agents when I have simple tasks to get done on all projects. Cleanup, running evals, etc. That whole day becomes parallel agents on easy tasks. Otherwise I do tight feedback loops on single agent (with subagents).

When running multi-agent I recommend keeping an eye on the flow of the work. Is it touching files that make sense? Has it been spiraling too long, is it pulling in packages? Things I can eyeball quickly without fully committing to that context. A full review of that sus diff would make me context switch, but seeing it's editing only files in a related part of the codebase is low effort.