[Research Preview] HydraFusion is live in GitHub Copilot CLI: Frontier quality via multi-model orchestration

[ebndev]

We are excited to introduce 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.

How to try it

HydraFusion is available to users on all GitHub Copilot plans through /experimental in GitHub Copilot CLI. Usage is based on the tokens consumed by the models HydraFusion uses, priced at each model’s standard rate.
To try HydraFusion in Copilot CLI:

1. Run /update to install the latest version
2. Run /experimental on
3. Run /model, then select HydraFusion (Research Preview)

How HydraFusion works

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:

• Single. One selected model solves the task directly.
• Cascade. An efficient model drafts a solution and a quality gate decides whether to accept it or escalate to a stronger model.
• Critique. One model drafts a result, an independent read-only critic from a different model family reviews it (following the same review pattern as Rubber Duck), and the drafting model revises once.

For further information, please check out our blog post on Project HydraFusion: https://gh.io/hydrafusion

Why we built HydraFusion

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.
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.

What we need from you

Try our research preview today. This preview is designed to learn which tasks benefit from compound workflows and how orchestration affects latency and cost in practice. When sharing feedback, please include copilot debug logs or your session ID through /session id

📍Frequently asked questions

Q: Where can I use it?

Today, only in GitHub Copilot CLI. It shipped in the latest release as an experimental research preview. The GitHub Copilot app and VS Code are both targeting September as a fast follow.

Q: What is the major difference between Auto and HydraFusion?

Both Auto and HydraFusion do the choosing for you. Auto selects one model per request. HydraFusion runs multiple models in a single turn, has them review and critique one another, and fuses the result. Auto picks the optimal model; HydraFusion picks the optimal workflow, possibly using multiple models.

• Progression: Auto V1 (Jan 2026, capacity/SKU-aware per-request selection) → Auto V2 aka. HyDRA (May 2026, intent-scored routing) → HydraFusion (Aug 2026, per-turn orchestration and cache-aware workflows).

Auto and HydraFusion are both intelligent model routing, and we expect them to come together into a single experience over time. We’re still evaluating what that looks like.

Q: Can I select which specific models HydraFusion draws from or exclude certain models?

Not today. HydraFusion picks from a curated mix, lighter models for straightforward work and stronger reasoning models for harder problems. The lineup shifts as new models ship and our evals show what performs best, so we don't publish a fixed roster. The point is that you get the right model without choosing one. We know some teams need more control here and we're looking into it.

Q: How does billing work for HydraFusion?

There is no separate HydraFusion charge. You pay for the constituent models it runs, so the cost of a turn is the sum of its phases.

Q: Why can't I see HydraFusion's output while it's working?

HydraFusion isn't a single model. It can run several models that draft, review, and revise before producing an answer. Those intermediate passes are working drafts that may be revised or discarded, so we show you the final reviewed result rather than text that could change moments later. We're working on showing more while it runs. Tell us what you would like to see.

Happy Coding!

[aditya81070]

Hey team, thanks for great feature, excited to try this. Just noticed one thing: when in the plan mode and trying to switch to HydraFusion model, it switches back to previously selected model. Can we add a warning or message which specify that HydraFusion will only work in normal mode.

[jukasper]

Hi @aditya81070 , thank you so much for this feedback. This seems to be a bug, we are currently investigating. So thanks for bringing this to our attention.