SAFugu Ultra Paid vs 
Claude Sonnet 5.5 Paid
Fugu Ultra vs Claude Sonnet 5.5 compared — price per token, context window, multimodality, openness and which to choose. Full 2026 breakdown.
Fugu Ultra — full profile › · Claude Sonnet 5.5 — full profile ›
Prices & specs refreshed from live data · olud.ai
Open-model prices = cheapest provider via OpenRouter; official maker rates may be higher.
$30 /M outputManaged API (no infra to run)
$10 /M outputManaged API (no infra to run)
Fugu Ultra vs Claude Sonnet 5.5 specs
| Spec | Fugu Ultra | Claude Sonnet 5.5 | Winner |
|---|---|---|---|
| Maker | Sakana AI | Anthropic | – |
| Type | Proprietary | Proprietary | – |
| Context window | 1M tokens | 1M tokens | = Tie |
| Input price | $5/M | $2/M | |
| Output price | $30/M | $10/M | |
| Vision / multimodal | Yes | Yes | = Tie |
| Tool / function calling | Yes | Yes | = Tie |
| Self-hostable | No (API only) | No (API only) | – |
| License | Proprietary | Proprietary | – |
Price gap & when to choose each
Claude Sonnet 5.5 is ~3.0× cheaper than Fugu Ultra on output tokens ($10 vs $30 per M tokens).
- You want frontier performance through a managed API
- You value reliability & ecosystem
- You don't want to manage infrastructure
- You want frontier performance through a managed API
- You want the lower output price
- You value reliability & ecosystem
- You don't want to manage infrastructure
Feature comparison
| Capability | Fugu Ultra | Claude Sonnet 5.5 |
|---|---|---|
| Open weights (downloadable) | ✗ | ✗ |
| Self-hostable | ✗ | ✗ |
| Runs fully offline | ✗ | ✗ |
| Vision / multimodal | ✓ | ✓ |
| Tool / function calling | ✓ | ✓ |
| 1M+ context window | ✓ | ✓ |
Benchmarks: Fugu Ultra vs Claude Sonnet 5.5
Independent benchmark scores measured by Artificial Analysis. Higher is better (except latency).
Benchmark data by Artificial Analysis.
How Fugu Ultra and Claude Sonnet 5.5 score
| Criterion | Fugu Ultra | Claude Sonnet 5.5 |
|---|---|---|
| Cost-efficiency | 3.0 | 3.5 |
| Context window | 5.0 | 5.0 |
| Openness | 1.5 | 1.5 |
| Self-hosting | 1.0 | 1.0 |
| Multimodality | 5.0 | 5.0 |
Scores come from live data — output price (cost), context length, open vs closed weights (openness & self-hosting) and vision/tool support (multimodality). Raw task quality isn't scored here; it depends on your benchmark — see the verdict.
What each model is
Fugu Ultra Paid
Fugu Ultra is the higher-performance model in Sakana AI's Fugu family. Rather than a single monolithic model, Fugu is a learned multi-agent orchestration system: a language model trained to route...
Claude Sonnet 5.5 Paid
Claude Sonnet 5.5 is Anthropic's Sonnet-class model for well-scoped everyday work, succeeding Claude Sonnet 5 as a direct upgrade. It is especially strong at building features, fixing bugs, and producing...
Other models in these families
These variants are tracked but not compared here — one page per family keeps the comparison readable.
Frequently asked questions
Fugu Ultra vs Claude Sonnet 5.5 — which is cheaper?
Claude Sonnet 5.5 is cheaper on output ($10/M vs $30/M).
Which has the larger context window?
Fugu Ultra offers the larger context window (1M tokens).
Fugu Ultra vs Claude Sonnet 5.5 — which should I pick in 2026?
Choose Claude Sonnet 5.5 for the lower output price ($10/M vs $30/M). Choose Fugu Ultra if you need the larger 1M context window.
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