One routes inside Copilot. One routes in front of everything.
HydraFusion is GitHub's cost-cutting router built into Copilot CLI. For each request it picks a Single, Cascade or Critique execution and, by GitHub's own numbers, cuts cost across its benchmarks. It's a real result, and it only works inside Copilot. OmnisRouter is a proxy you run yourself. Change one base URL and any client routes through it to the cheapest capable model, with a receipt on every request. Here's a straight comparison.
How they compare
| Dimension | HydraFusion (GitHub Copilot) | OmnisRouter |
|---|---|---|
| Where it runs | Inside GitHub Copilot CLI | Self-hosted, single process (BYOK) |
| Works with | GitHub Copilot only | Any client: Claude Code, Cursor, Codex, direct API |
| How it routes | Single / Cascade / Critique per request | Cheapest capable model by semantic intent |
| Routing logic | Closed (Microsoft research preview) | Open, Apache-2.0, rebuildable from public data |
| Per-request receipt | No | Chosen model, confidence, alternatives, estimated saving |
| Hard caps and kill switch | None | Local per-project and per-user caps (with OmnisVigil) |
| Keys and billing | Copilot plan, per token | Your provider keys, your own bills |
| Cost-quality proof | GitHub's own benchmarks | Open OmnisBench, re-runnable on fresh tasks |
What HydraFusion is good at
If your team lives entirely inside GitHub Copilot, HydraFusion is a genuinely useful, zero-setup way to spend less. It's one flag in the CLI, it's backed by Microsoft, and its Single, Cascade and Critique strategies are more considered than a plain model swap. By GitHub's own figures it cut cost on all three of its benchmarks (67% on TerminalBench 2.1, 36% on DeepSWE, 65% on CheckpointBench) while holding Opus 5 quality on one of the three. The fact that Microsoft shipped it tells you the problem is real.
What OmnisRouter does differently
OmnisRouter isn't tied to one tool. Change one base URL and Claude Code, Cursor, Codex or your own app all route through it, so it covers the whole bill rather than the Copilot slice of it. The routing model ships in the repo and rebuilds from public data, so the same inputs produce the same decision, and every response carries a receipt: the chosen model, the confidence, the alternatives and the estimated saving. You bring your own provider keys, they're encrypted at rest, and prompt content leaves your machine only to the chosen upstream. And where HydraFusion lowers a request's price, OmnisRouter can also stop the spend: real local caps and a kill switch (through OmnisVigil) that HydraFusion doesn't offer at all.
Two more angles on the same comparison
On the benchmark →
OmnisBench is the open way to check HydraFusion's cost-quality claim on fresh, contamination-controlled tasks, rather than the vendor's own set.
On governance →
OmnisVigil governs spend across every tool, with budgets, attribution and a kill switch, where HydraFusion cuts one request's cost and stops there.
Pick based on the constraint
HydraFusion
Your team is entirely on GitHub Copilot and you want a lower per-request cost with no setup.
OmnisRouter
You run more than one coding tool, or you want the routing open, self-hosted, capped and inspectable across your whole bill.
Route on your own box in minutes
Run one process, add a key, point any client at it. It routes to the cheapest capable model and hands you a receipt, whatever tool you use.