Project HydraFusion: Frontier quality via multi-model orchestration

Providing developers the best model for the task at hand has always been our goal. Earlier this year, we made that easier by launchingAuto model selection,which reviews your task and matches it to the best-suited model for that task.

Today, we’re introducing Project HydraFusion, a research preview that delivers frontier intelligence through runtime orchestration. It creates a full execution plan, choosing from models across multiple providers to draft, critique and revise, or cascade to more powerful models to complete your task.

HydraFusion fills a key role in our overall strategy to deliver automated semantic routing between local, cloud, and compound models. For developers, that complexity stays behind the scenes: you select HydraFusion like any other model, and it chooses a workflow that balances performance, cost, and latency for each task.

HydraFusion treats workflow selection as an optimization problem. It uses capability signals for reasoning, code generation, debugging, and tool use to select the most efficient execution pattern to meet the quality bar.

For each request, HydraFusion currently chooses one of three execution patterns:

Each pattern addresses a different quality-to-cost trade-off.Singlepreserves speed and efficiency when one model can solve the task directly.Cascadegives an efficient model the first attempt while retaining a path to stronger inference when the candidate does not clear the acceptance gate.Critiqueadds an independent perspective for tasks where review is more useful than another unaided attempt.

In offline evaluations across three agentic coding benchmarks, HydraFusion consistently demonstrated frontier-level quality with substantial estimated cost savings. On TerminalBench 2.1, it improved verified task quality by 4.9 percentage points at 67% lower estimated cost compared with Claude Opus 5.

Let’s dive into the approach, the results, and the benchmarks.

Developers already coordinate models manually: choosing one for a task, asking another to review the work, or escalating a difficult problem to a more capable model. HydraFusion brings that familiar process into the runtime. You choose HydraFusion once and stay focused on your task while it manages the models and workflow behind the scenes.

The key is selectivity. Some coding tasks can be solved directly, while others benefit from review, revision, or escalation. HydraFusion evaluates each request and chooses the least complex workflow expected to meet its needs, using additional model calls only when they are likely to improve the result. This adaptive approach balances quality, cost, and latency across models.

As the model frontier advances, so does HydraFusion. When new models become available in GitHub Copilot, we can evaluate and incorporate them into its model pool, bringing their strengths to the tasks best suited to them.

Turning adaptive multi-model orchestration into one dependable coding experience requires careful control of execution, review, cost, and repository state. HydraFusion is built around five operating principles: