Fugu Ultra: pricing, context and performance
Fugu Ultra in numbers: price per token, context window, independent benchmark scores and comparable models, based on public data checked on October 22, 2026.
Data as of October 22, 2026
Key figures
| Developer | Sakana AI |
|---|---|
| Released | June 15, 2026 |
| Context window | 1,000,000 tokens (≈ 1,500 pages) |
| Maximum output | 1,000,000 tokens |
| Input price | $5 per million tokens (developer's price) |
| Output price | $30 per million tokens |
| Open weights | No |
| Reasoning mode | Yes |
| Tool calling | Yes |
| Structured output (JSON) | Yes |
| Accepted inputs | text, image |
| Providers offering it | 14 |
Fugu Ultra at a glance
Sakana AI released Fugu Ultra on June 15, 2026. It has a reasoning mode: it can "think" before answering, which helps with multi-step problems but uses more tokens, and therefore more money. Its weights are not published, so it only runs remotely, through the Sakana AI API or partner hosts (14 listed on models.dev). That makes it 4 months old as of October 22, 2026.
We file it under frontier models (24 models in this category on the site).
What it costs
Fugu Ultra costs $5 per million input tokens and $30 per million output tokens (developer's price, checked on October 22, 2026).
In practice, an agent task that reads 20,000 tokens and writes 2,000 costs about $0.16, or $160 for 1,000 such tasks.
That is 2.1 times the median output price of frontier models ($14.5).
Tokens read back from cache cost $0.50 per million, which helps an agent that keeps resending the same context.
To estimate your own budget, use the agent cost calculator.
Measured performance
As of October 22, 2026, Epoch AI publishes no score for Fugu Ultra on our basket's benchmarks. To place it, rely on its specifications and price, then test it on your own cases.
Technical specifications
Its context window reaches 1,000,000 tokens, roughly 1,500 pages of text at 500 words per page: enough to load a whole book or a mid-sized codebase. A single answer can run to 1,000,000 tokens.
It accepts as input: text and image.
It can call tools (functions, APIs) and return structured JSON output, which makes it a possible foundation for an AI agent.
Who is it for?
Given its category, Fugu Ultra is mainly aimed at hard tasks where quality matters more than cost: deep reasoning, complex code, long analyses.
Its very large context window makes it worth considering for analysing large sets of documents in a single request.
Before adopting it, test it on your own examples: benchmarks measure standard tasks, not your job.
Comparable models
In the same category, the models closest to Fugu Ultra are:
- GPT-5.5 (OpenAI, index 89)
- Fugu Ultra v2 (Sakana AI, $30 per million output tokens)
- Claude Opus 5 (Anthropic, index 92.7)
- Claude Opus 5.5 (Anthropic, index 95.9)
Similar models
- GPT-5.5 · OpenAI · index 89
- Fugu Ultra v2 · Sakana AI
- Claude Opus 5 · Anthropic · index 92.7
- Claude Opus 5.5 · Anthropic · index 95.9
Other Sakana AI models
- Fugu Max · September 11, 2026
- Sakana Namazu · August 3, 2026
Frequently asked questions
How much does Fugu Ultra cost?
As of October 22, 2026, Fugu Ultra costs $5 per million input tokens and $30 per million output tokens (developer's price). A task that reads 20,000 tokens and writes 2,000 costs about $0.16.
What is the context window of Fugu Ultra?
1,000,000 tokens, roughly 1,500 pages of text. An answer can reach 1,000,000 tokens.
Is Fugu Ultra open source?
No. It is a closed Sakana AI model, available only through an API.
When was Fugu Ultra released?
Fugu Ultra was released on June 15, 2026, according to models.dev.
Can you build an agent with Fugu Ultra?
Yes: it can call tools and return structured JSON, the two basic building blocks of an agent.
Data sources
- Models.dev — Model data: models.dev (open-source project)
- OpenRouter — Market prices cross-checked with OpenRouter
Data as of October 22, 2026
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