Fugu Ultra v2.0 vs GPT-4.1 Mini

Sakana AI · Global  |  OpenAI · US · Updated June 2026

Quick verdict

Pick Fugu Ultra v2.0 for sakana's own evaluation reports best-or-joint-best results on 5 of 8 benchmarks tested, including a 74.3 on the deepswe coding-repair benchmark or claims to outperform flagship models like gpt-6 astra and claude fable 5.1 despite its underlying orchestration pool reportedly excluding both of them. Pick GPT-4.1 Mini for very cheap high-volume text work at $0.40 in / $1.60 out per million tokens or instruction following above its weight class — 84.1% on ifeval, beating gpt-4o. On a tight budget at scale, GPT-4.1 Mini is the value pick.

Fugu Ultra v2.0 (Sakana AI) and GPT-4.1 Mini (OpenAI) are two of the models people most often weigh against each other in 2026. Fugu Ultra v2.0 is sakana AI's flagship multi-agent orchestration model, claiming best-or-joint-best results on 5 of 8 self-reported benchmarks against monolithic frontier models — $5/$30 per million tokens. GPT-4.1 Mini is a cheap, fast 1M-context workhorse with strong instruction following but weak coding — already retired from ChatGPT. They diverge most on price and context window — each quantified below from the models' real specs.

Key differences at a glance

Side-by-side specs

SpecFugu Ultra v2.0GPT-4.1 Mini
ProviderSakana AI (Global) OpenAI (US)
ReleasedSeptember 10, 2026 April 14, 2025
Context window1M tokens (~1,500 pages) 1M (~1,571 pages)
Price (in/out)$5/$30 per 1M tokens $0.4/$1.6 per 1M tokens
Open weight?No — API only No — API only
Modalitiestext text, image, code
SWE-Bench VerifiedNot published 23.6%
MRCR v2 @ 1MNot published Not published

Who wins what

Sakana's own evaluation reports best-or-joint-best results on 5 of 8 benchmarks tested, including a 74.3 on the DeepSWE coding-repair benchmark

Fugu Ultra v2.0

GPT-4.1 Mini is comparatively weak here — weak at agentic coding — its 23.6% on SWE-Bench Verified sits below GPT-4o's 33.2%

Claims to outperform flagship models like GPT-6 Astra and Claude Fable 5.1 despite its underlying orchestration pool reportedly excluding both of them

Fugu Ultra v2.0

Sakana AI's flagship multi-agent orchestration model, claiming best-or-joint-best results on 5 of 8 self-reported benchmarks against monolithic frontier models — $5/$30 per million tokens — and it is the newer of the two.

1M-token context window

Fugu Ultra v2.0

Fugu Ultra v2.0 lists 1M-token context window among its strengths; GPT-4.1 Mini does not.

Very cheap high-volume text work at $0.40 in / $1.60 out per million tokens

GPT-4.1 Mini

At $0.4/$1.6 per 1M tokens it undercuts Fugu Ultra v2.0 ($5/$30 per 1M tokens), and that gap compounds at volume.

Instruction following above its weight class — 84.1% on IFEval, beating GPT-4o

GPT-4.1 Mini

Fugu Ultra v2.0 is comparatively weak here — pricing rises to roughly $10/$45 per million tokens for prompts above 272K tokens

Multi-turn coherence for its tier — 35.8% on MultiChallenge, roughly 1.8x GPT-4o mini

GPT-4.1 Mini

Fugu Ultra v2.0 is comparatively weak here — not a single trained model — Sakana describes Fugu as "a Multi-Agent System, Delivered as One Model" that dynamically routes tasks across a pool of other models, so head-to-head benchmark framing against monolithic frontier models should be read skeptically

Lowest cost at scale

GPT-4.1 Mini

At $0.4/$1.6 per 1M tokens, it is the cheaper of the two — the gap dominates the bill on high-volume workloads.

Which should you pick?

A cost-sensitive startup shipping high volume

GPT-4.1 Mini

At $0.4/$1.6 per 1M tokens it undercuts Fugu Ultra v2.0, and on millions of tokens that margin decides the monthly bill.

Someone analysing very long documents or codebases

GPT-4.1 Mini

Larger 1M window fits more in one prompt.

Anyone whose priority is sakana's own evaluation reports best-or-joint-best results on 5 of 8 benchmarks tested, including a 74.3 on the deepswe coding-repair benchmark

Fugu Ultra v2.0

It is specifically built for that.

Anyone whose priority is very cheap high-volume text work at $0.40 in / $1.60 out per million tokens

GPT-4.1 Mini

That is its strongest area.

Fugu Ultra v2.0: where it fits

Sakana AI's flagship multi-agent orchestration model, claiming best-or-joint-best results on 5 of 8 self-reported benchmarks against monolithic frontier models — $5/$30 per million tokens. Released September 10, 2026 by Sakana AI, it is built for sakana's own evaluation reports best-or-joint-best results on 5 of 8 benchmarks tested, including a 74.3 on the DeepSWE coding-repair benchmark, claims to outperform flagship models like GPT-6 Astra and Claude Fable 5.1 despite its underlying orchestration pool reportedly excluding both of them, and 1M-token context window.

Its trade-offs are real: not a single trained model — Sakana describes Fugu as "a Multi-Agent System, Delivered as One Model" that dynamically routes tasks across a pool of other models, so head-to-head benchmark framing against monolithic frontier models should be read skeptically, pricing rises to roughly $10/$45 per million tokens for prompts above 272K tokens, and benchmark comparisons against GPT-6 Astra and Claude Fable 5.1 are Sakana's own self-reported figures, not independently verified head-to-head scores. At $5 in / $30 out per million tokens, it sits in the premium price band.

GPT-4.1 Mini: where it fits

A cheap, fast 1M-context workhorse with strong instruction following but weak coding — already retired from ChatGPT. Released April 14, 2025 by OpenAI, it is built for very cheap high-volume text work at $0.40 in / $1.60 out per million tokens, instruction following above its weight class — 84.1% on IFEval, beating GPT-4o, multi-turn coherence for its tier — 35.8% on MultiChallenge, roughly 1.8x GPT-4o mini, and a full 1M context at flat pricing, with no long-context premium.

Its trade-offs: weak at agentic coding — its 23.6% on SWE-Bench Verified sits below GPT-4o's 33.2%, retired from ChatGPT in February 2026, and OpenAI's own docs now point users to GPT-5 mini instead, and a June 2024 knowledge cutoff, now roughly two years stale, and no reasoning mode. At $0.4 in / $1.6 out per million tokens, it sits in the budget price band.

The bottom line for this matchup

Fugu Ultra v2.0 and GPT-4.1 Mini overlap enough that the right pick depends on your specific job. GPT-4.1 Mini costs less per token; GPT-4.1 Mini holds the larger context; and each leads in its own area — Fugu Ultra v2.0 for sakana's own evaluation reports best-or-joint-best results on 5 of 8 benchmarks tested, including a 74.3 on the deepswe coding-repair benchmark, GPT-4.1 Mini for very cheap high-volume text work at $0.40 in / $1.60 out per million tokens. Rather than crowning one, run the same hard task through both once and let the results decide.

Want both Fugu Ultra v2.0 and GPT-4.1 Mini without two subscriptions? LumiChats gives you these plus 40+ models under one ₹69/day pass (about $1/day) — draft with one, cross-check with the other.

See pricing

Frequently asked questions

Is Fugu Ultra v2.0 or GPT-4.1 Mini better for coding?

Public SWE-Bench figures are not available for Fugu Ultra v2.0, so the honest test is your own repository — run an identical real bug through both. By design, Fugu Ultra v2.0 leans toward sakana's own evaluation reports best-or-joint-best results on 5 of 8 benchmarks tested, including a 74.3 on the deepswe coding-repair benchmark while GPT-4.1 Mini leans toward very cheap high-volume text work at $0.40 in / $1.60 out per million tokens, and that positioning usually predicts which feels better on your codebase.

Which is cheaper, Fugu Ultra v2.0 or GPT-4.1 Mini?

GPT-4.1 Mini is cheaper — $5/$30 per 1M tokens vs $0.4/$1.6 per 1M tokens, roughly 13× apart on input.

Which has the bigger context window?

Effectively neither — 1M tokens vs 1M is a difference of a few percent. Remember advertised ≠ usable: recall typically degrades before the ceiling.

Can I use both Fugu Ultra v2.0 and GPT-4.1 Mini together?

Yes — a multi-model platform like LumiChats gives you Fugu Ultra v2.0, GPT-4.1 Mini and 40+ others under one ₹69/day pass (about $1/day), so you can draft with one and cross-check with the other instead of buying two subscriptions.

Which is newer, Fugu Ultra v2.0 or GPT-4.1 Mini?

Fugu Ultra v2.0 — released September 10, 2026, about 17 months after GPT-4.1 Mini.

Related comparisons

Specifications and benchmarks reflect publicly reported figures as of June 2026 and may change as providers release updates. Always verify on your own workload.