Fugu Ultra vs Gemini 3.1 Pro Preview
Fugu Ultra (2026) and Gemini 3.1 Pro Preview (2026) are frontier reasoning models from Sakana AI and Google DeepMind. Fugu Ultra ships a 1m-token context window, while Gemini 3.1 Pro Preview ships a 1m-token context window. On SWE-bench Pro, Fugu Ultra leads by 19.5 pts. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
Fugu Ultra is safer overall; choose Gemini 3.1 Pro Preview when coding workflow support matters.
Decision scorecard
Local evidence first| Signal | Fugu Ultra | Gemini 3.1 Pro Preview |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | multimodal apps, tool-calling agents, and long-context analysis |
| Decision fit | Coding, RAG, and Agents | Coding, RAG, and Agents |
| Context window | 1m | 1m |
| Cheapest output | $30/1M tokens | $12/1M tokens |
| Provider routes | 2 tracked | 5 tracked |
| Shared benchmarks | SWE-bench Pro leader | 4 shared |
Decision tradeoffs
- Fugu Ultra holds a shared-benchmark lead on SWE-bench Pro, ahead by 19.5 points.
- Fugu Ultra uniquely exposes Reasoning in local model data.
- Local decision data tags Fugu Ultra for Coding, RAG, and Agents.
- Gemini 3.1 Pro Preview holds a shared-benchmark lead on Humanity's Last Exam, ahead by 1.4 points.
- Gemini 3.1 Pro Preview has the lower cheapest tracked output price at $12/1M tokens.
- Gemini 3.1 Pro Preview has broader tracked provider coverage for fallback and procurement flexibility.
- Gemini 3.1 Pro Preview uniquely exposes Code execution in local model data.
- Local decision data tags Gemini 3.1 Pro Preview for Coding, RAG, and Agents.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Fugu Ultra
$11,500
Cheapest tracked route/tier: Sakana AI <=272K tokens
Gemini 3.1 Pro Preview
$4,600
Cheapest tracked route/tier: Google AI Studio
Estimated monthly gap: $6,900. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on Vercel AI Gateway; start route-level A/B tests there.
- Gemini 3.1 Pro Preview is $18/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Reasoning before moving production traffic.
- Gemini 3.1 Pro Preview adds Code execution in local capability data.
- Provider overlap exists on Vercel AI Gateway; start route-level A/B tests there.
- Fugu Ultra is $18/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Check replacement coverage for Code execution before moving production traffic.
- Fugu Ultra adds Reasoning in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-06-22 | 2026-02-19 |
| Context window | 1m | 1m |
| Parameters | — | — |
| Architecture | Composition of Experts | Decoder Only |
| License | Proprietary | Proprietary |
| Openness | Proprietary | Proprietary |
| Commercial use | Commercial use: conditional | Commercial use: conditional |
| Knowledge cutoff | - | 2025-01 |
Pricing and availability
| Pricing attribute | Fugu Ultra | Gemini 3.1 Pro Preview |
|---|---|---|
| Input price |
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| Output price |
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| Providers |
Capabilities
| Capability | Fugu Ultra | Gemini 3.1 Pro Preview |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | No |
| Function calling | Yes | Yes |
| Tool use | Yes | Yes |
| Structured outputs | Yes | Yes |
| Code execution | No | Yes |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
| Benchmark | Fugu Ultra | Gemini 3.1 Pro Preview |
|---|---|---|
| SWE-bench Pro | 73.7 | 54.2 |
| Google-Proof Q&A | 95.5 | 94.3 |
| LiveCodeBench | 93.2 | 91.7 |
| Humanity's Last Exam | 50.0 | 51.4 |
Deep dive
On shared benchmark coverage, SWE-bench Pro has Fugu Ultra at 73.7 and Gemini 3.1 Pro Preview at 54.2, with Fugu Ultra ahead by 19.5 points; Google-Proof Q&A has Fugu Ultra at 95.5 and Gemini 3.1 Pro Preview at 94.3, with Fugu Ultra ahead by 1.2 points; LiveCodeBench has Fugu Ultra at 93.2 and Gemini 3.1 Pro Preview at 91.7, with Fugu Ultra ahead by 1.5 points. The largest visible gap is 19.5 points on SWE-bench Pro, which matters most when that benchmark mirrors your workload. Treat isolated benchmark wins as directional, because provider routing, prompt style, and tool access can move real application results.
The capability footprint differs most on reasoning mode: Fugu Ultra and code execution: Gemini 3.1 Pro Preview. Both models share vision, multimodal input, function calling, and tool use, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
For cost, Fugu Ultra lists tiered pricing: <=272K tokens is $5/1M input and $30/1M output; >272K tokens is $10/1M input and $45/1M output, while Gemini 3.1 Pro Preview lists tiered pricing: 0-200,001t is $2/1M input and $12/1M output; 200,001t+ is $4/1M input and $18/1M output. A 70/30 input-output blend puts Gemini 3.1 Pro Preview lower by about $7.50 per million blended tokens. For tiered rows, this cheapest-track view can understate interactive or fast-lane spend, so compare the tier you will actually use. Availability is 2 providers versus 5, so concentration risk also matters.
Choose Fugu Ultra when reasoning depth are central to the workload. Choose Gemini 3.1 Pro Preview when coding workflow support, lower cheapest-tier input-token cost, and broader provider choice are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship.
FAQ
Which has a larger context window, Fugu Ultra or Gemini 3.1 Pro Preview?
Fugu Ultra supports 1m tokens, while Gemini 3.1 Pro Preview supports 1m tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Which is cheaper, Fugu Ultra or Gemini 3.1 Pro Preview?
Fugu Ultra lists tiered pricing: <=272K tokens is $5/1M input and $30/1M output; >272K tokens is $10/1M input and $45/1M output. Gemini 3.1 Pro Preview lists tiered pricing: 0-200,001t is $2/1M input and $12/1M output; 200,001t+ is $4/1M input and $18/1M output. Compare the tier you will actually use; cheap async pricing can overstate savings for interactive workflows. Provider discounts or batch pricing can still change the final bill.
Is Fugu Ultra or Gemini 3.1 Pro Preview open source?
Fugu Ultra is listed under Proprietary. Gemini 3.1 Pro Preview is listed under Proprietary. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for vision, Fugu Ultra or Gemini 3.1 Pro Preview?
Both Fugu Ultra and Gemini 3.1 Pro Preview expose vision. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface.
Which is better for multimodal input, Fugu Ultra or Gemini 3.1 Pro Preview?
Both Fugu Ultra and Gemini 3.1 Pro Preview expose multimodal input. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface.
Where can I run Fugu Ultra and Gemini 3.1 Pro Preview?
Fugu Ultra is available on Sakana AI and Vercel AI Gateway. Gemini 3.1 Pro Preview is available on Google AI Studio, GCP Vertex AI, OpenRouter, Replicate API, and Vercel AI Gateway. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-06-22. Data sourced from public model cards and provider documentation.