Project HydraFusion is a research preview jointly developed by GitHub and Microsoft, released on September 4, 2026 in GitHub Copilot CLI (via the /experimental command). HydraFusion uses runtime multi-model orchestration: for each task it builds a full execution plan and selects one of three patterns — Single (one model), Cascade (an efficient model drafts a solution while a quality gate decides whether to escalate to a stronger model), or Critique (one model drafts, another reviews, and the first revises). In offline evaluations HydraFusion matched or exceeded the Claude Opus 5 baseline while reducing estimated workflow cost by 36–67% across three benchmarks (TerminalBench 2.1, DeepSWE, CheckpointBench). It is available on all Copilot plans, billed by tokens consumed.
