Sakana AI splits its model-router in two -- and Fugu Ultra v2 beats the frontier models it refuses to put in its own pool

Sakana AI released two new models on September 10 -- Fugu Max and Fugu Ultra v2 -- built around a different idea than most model launches: neither is a foundation model Sakana trained itself. Both are orchestrators, systems that take a single request, decide which of several other companies' models is best suited to each part of it, and stitch the results into one answer through one API.

Fugu Max is the cost-first version -- $2 per million input tokens, $6 per million output tokens -- and Sakana says it posts the best overall score on six of its own benchmarks, including Terminal Bench 2.1 and GPQA Diamond. Fugu Ultra v2, the capability-first version, costs more ($5/$30 per million tokens, plus an undisclosed long-context surcharge above 272,000 tokens) and claims the best or joint-best score on five of eight benchmarks -- among them a 48.3 on a visual-reasoning test called Chartography against 27.3 for Claude Opus 5 and 29.5 for Claude Fable 5, and a 74.3 on a software-engineering benchmark Sakana says beats models priced three to five times higher per token.

Every one of those numbers is Sakana's own benchmark suite, run by Sakana, not an independent aggregator -- worth remembering before treating a self-reported score as equivalent to a measured one.

The stranger detail is which models Fugu Ultra v2 is actually allowed to call on. Claude Fable 5, Fable 5.1, and GPT-6 Astra are all excluded from its agent pool -- the same models it's benchmarked against -- because, per Sakana, they aren't models it can access on terms it controls, and depending on a rival's API exposes Fugu to vendor lock-in, API revocations, and sudden service cutoffs. It's an unusual position for a product whose entire pitch is stitching together other companies' models: independence from the very labs it's trying to beat.

Both models are live now through an OpenAI-compatible hosted API -- there's no open-weights version to self-host. Neither is available in the EU or EEA yet; Sakana attributes that to ongoing GDPR compliance work rather than a permanent decision.