Fugu Ultra vs Phi-4 Mini Reasoning
Fugu Ultra (2026) and Phi-4 Mini Reasoning (2026) are frontier-tier reasoning models from Sakana AI and Microsoft Research. Fugu Ultra ships a 1m-token context window, while Phi-4 Mini Reasoning ships a 128k-token context window. On Google-Proof Q&A, Fugu Ultra leads by 43.5 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 fits 8x more tokens; pick it for long-context work and Phi-4 Mini Reasoning for tighter calls.
Decision scorecard
Local evidence first| Signal | Fugu Ultra | Phi-4 Mini Reasoning |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | reasoning-heavy apps |
| Decision fit | Coding, RAG, and Agents | Long context |
| Context window | 1m | 128k |
| Cheapest output | $30/1M tokens | - |
| Provider routes | 2 tracked | 0 tracked |
| Shared benchmarks | Google-Proof Q&A leader | 1 shared |
Decision tradeoffs
- Fugu Ultra holds a shared-benchmark lead on Google-Proof Q&A, ahead by 43.5 points.
- Fugu Ultra has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Fugu Ultra has broader tracked provider coverage for fallback and procurement flexibility.
- Fugu Ultra uniquely exposes Vision, Multimodal, and Function calling in local model data.
- Local decision data tags Fugu Ultra for Coding, RAG, and Agents.
- Local decision data tags Phi-4 Mini Reasoning for Long context.
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
Phi-4 Mini Reasoning
Unavailable
No complete token price in local provider data
Cost delta unavailable until both models have sourced input and output token prices.
Switch friction
- No overlapping tracked provider route is sourced for Fugu Ultra and Phi-4 Mini Reasoning; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Vision, Multimodal, and Function calling before moving production traffic.
- No overlapping tracked provider route is sourced for Phi-4 Mini Reasoning and Fugu Ultra; plan for SDK, billing, or endpoint changes.
- Fugu Ultra adds Vision, Multimodal, and Function calling in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-06-22 | 2026-05-16 |
| Context window | 1m | 128k |
| Parameters | — | 3.8B |
| Architecture | Composition of Experts | - |
| License | Proprietary | MITOSI-approved |
| Openness | Proprietary | Open source |
| Commercial use | Commercial use: conditional | Commercial use: permitted |
| Knowledge cutoff | - | 2025-02 |
Pricing and availability
| Pricing attribute | Fugu Ultra | Phi-4 Mini Reasoning |
|---|---|---|
| Input price |
| - |
| Output price |
| - |
| Providers | - |
Capabilities
| Capability | Fugu Ultra | Phi-4 Mini Reasoning |
|---|---|---|
| Vision | Yes | No |
| Multimodal | Yes | No |
| Reasoning | Yes | Yes |
| Function calling | Yes | No |
| Tool use | Yes | No |
| Structured outputs | Yes | No |
| Code execution | No | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
| Benchmark | Fugu Ultra | Phi-4 Mini Reasoning |
|---|---|---|
| Google-Proof Q&A | 95.5 | 52.0 |
Deep dive
On shared benchmark coverage, Google-Proof Q&A has Fugu Ultra at 95.5 and Phi-4 Mini Reasoning at 52, with Fugu Ultra ahead by 43.5 points. The largest visible gap is 43.5 points on Google-Proof Q&A, 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 vision: Fugu Ultra, multimodal input: Fugu Ultra, function calling: Fugu Ultra, tool use: Fugu Ultra, and structured outputs: Fugu Ultra. Both models share reasoning mode, 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.
Pricing coverage is uneven: Fugu Ultra has $5/1M input tokens and Phi-4 Mini Reasoning has no token price sourced yet. Provider availability is 2 tracked routes versus 0. Treat unknown pricing as an integration gap, then verify the route you will actually call before estimating production spend.
Choose Fugu Ultra when long-context analysis, larger context windows, and broader provider choice are central to the workload. Choose Phi-4 Mini Reasoning when provider fit 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 Phi-4 Mini Reasoning?
Fugu Ultra supports 1m tokens, while Phi-4 Mini Reasoning supports 128k tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Is Fugu Ultra or Phi-4 Mini Reasoning open source?
Fugu Ultra is listed under Proprietary. Phi-4 Mini Reasoning is listed under MIT. 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 Phi-4 Mini Reasoning?
Fugu Ultra has the clearer documented vision signal in this comparison. If vision is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Which is better for multimodal input, Fugu Ultra or Phi-4 Mini Reasoning?
Fugu Ultra has the clearer documented multimodal input signal in this comparison. If multimodal input is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for reasoning mode, Fugu Ultra or Phi-4 Mini Reasoning?
Both Fugu Ultra and Phi-4 Mini Reasoning expose reasoning mode. 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 Phi-4 Mini Reasoning?
Fugu Ultra is available on Sakana AI and Vercel AI Gateway. Phi-4 Mini Reasoning is available on the tracked providers still being sourced. 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.