Project HydraFusion: Frontier quality via multi-model orchestration

GitHub introduced Project HydraFusion, a research preview in GitHub Copilot CLI that builds per-request execution plans across multiple providers. It selects among Single, Cascade, or Critique patterns. On TerminalBench 2.1, HydraFusion improved verified task quality by 4.9 percentage points at 67% lower estimated cost versus Claude Opus 5.