Project HydraFusion: Frontier quality via multi-model orchestration

GitHub’s research preview that stops asking you to pick a model. HydraFusion looks at each request and chooses one of three shapes: single, where one model just does it; cascade, where a cheap model drafts and only escalates if it fails a quality gate; and critique, where one model drafts, a different one reviews, and the first revises.

The reported numbers are about cost rather than capability. Against Claude Opus 5 it claims 67% lower estimated cost with 4.9 points better quality on TerminalBench 2.1, 65% lower cost at roughly parity on CheckpointBench, and 36% lower cost for 1.5 points worse on DeepSWE.

Worth the usual caution: these are GitHub’s own figures for GitHub’s own system, and “estimated cost” is doing some work. But the critique pattern is the same instinct as Copilot’s rubber duck agent, and the routing idea is one this linklog has seen fail before, in everyone is building LLM routers, we deprecated ours. Available through Copilot CLI under /experimental.