Google Antigravity added /boost, a three-phase multi-agent mode.

An orchestrator decomposes the prompt, specialized subagents run implementation, investigation and local verification in isolated environments in parallel, then a synthesis pass validates against test suites and edge cases (Antigravity docs). Google positions it for the seconds-to-hours band between the default single-agent assistant and longer-horizon /teamwork, naming concurrency bugs, algorithmic optimization, multi-file refactoring and root-cause investigation. Paid plans only, and the docs disclose neither the underlying models nor the token cost, which for a fan-out mode is the number you most need.