Agentic
Directional only- Claude Opus 4.5
- 62.6
- Sakana Fugu-Ultra
- 82.1
- Weighted basis
- 2 vs 1 rows
- Reading
- Directional only
Claude Opus 4.5 vs Sakana Fugu-Ultra
Updated August 13, 2026. Public scores include evidence status and uncertainty. They are not guarantees for a specific workload.
Decision reading
At least one model is not scored in the current public ranking lane, so the page does not name an overall quality winner.
5 results are shared. Category rows based on different benchmark sets are marked directional and do not name a winner.
Which one for your work
Recommendations appear only when a shared evidence basis or an explicit operating constraint supports the call. Secondary and unsupported use cases stay disclosed below the initial list.
Long documents
Prompts that approach the documented context limit
Sakana Fugu-Ultra
Sakana Fugu-Ultra has the larger documented context window.
Confidence: documented
Show secondary and unsupported calls
Coding work
Code generation, repair, and software-engineering tasks
Not enough matched evidence
The category averages use different weighted benchmark sets, so they are directional rather than like-for-like.
Confidence: limited
Agentic work
Tool use, computer use, and multi-step task completion
Not enough matched evidence
The category averages use different weighted benchmark sets, so they are directional rather than like-for-like.
Confidence: limited
Chat turn cost
1K fresh input + 500 output tokens
Not enough matched evidence
A complete comparable API-rate estimate is not available for both models.
Confidence: listed-rates
Cache-heavy agent loop cost
200K cached + 20K fresh input + 10K output tokens
Not enough matched evidence
The page does not recommend a cost winner because at least one model cannot fit the stated workload in one request. Claude Opus 4.5 does not fit this workload in one request. Claude Opus 4.5 has no published cached-input rate, so cached tokens use its listed input rate. Sakana Fugu-Ultra has no comparable published API token rate.
Confidence: rate-fallback
Repository review cost
50K fresh input + 3K output tokens
Not enough matched evidence
A complete comparable API-rate estimate is not available for both models.
Confidence: listed-rates
What is actually comparable
Shared results can support a head-to-head reading. Results present for only one model describe coverage, not superiority.
40 Claude Opus 4.5 only
5 Shared
6 Sakana Fugu-Ultra only
- Shared results
- 5
- Claude Opus 4.5 only
- 40
- Sakana Fugu-Ultra only
- 6
- Like-for-like categories
- 0 / 8
4 categories use different evidence sets. Those rows remain visible for coverage context but do not name a winner.
Category results, on a stated basis
Each row states whether both averages use the same weighted benchmark set. Directional and not-comparable rows remain visible, but they never receive a winner in this template.
Coding
Directional only- Claude Opus 4.5
- 71.7
- Sakana Fugu-Ultra
- 64.5
- Weighted basis
- 2 vs 2 rows
- Reading
- Directional only
Knowledge
Directional only- Claude Opus 4.5
- 58.1
- Sakana Fugu-Ultra
- 95.5
- Weighted basis
- 4 vs 1 rows
- Reading
- Directional only
Multimodal
Directional only- Claude Opus 4.5
- 69.9
- Sakana Fugu-Ultra
- 86.6
- Weighted basis
- 2 vs 1 rows
- Reading
- Directional only
Reasoning
Not comparable- Claude Opus 4.5
- 64.4
- Sakana Fugu-Ultra
- 93.6
- Weighted basis
- 1 vs 1 rows
- Reading
- Not comparable
Math
Not comparable- Claude Opus 4.5
- 57.5
- Sakana Fugu-Ultra
- Not measured
- Weighted basis
- 4 vs 0 rows
- Reading
- Not comparable
Multilingual
Not comparable- Claude Opus 4.5
- 85.7
- Sakana Fugu-Ultra
- Not measured
- Weighted basis
- 1 vs 0 rows
- Reading
- Not comparable
Instruction following
Not comparable- Claude Opus 4.5
- 69.5
- Sakana Fugu-Ultra
- Not measured
- Weighted basis
- 2 vs 0 rows
- Reading
- Not comparable
| Category | Claude Opus 4.5 | Sakana Fugu-Ultra | Weighted basis | Reading |
|---|---|---|---|---|
| Agentic | 62.6 | 82.1 | Directional only2 vs 1 rows | Directional only |
| Coding | 71.7 | 64.5 | Directional only2 vs 2 rows | Directional only |
| Knowledge | 58.1 | 95.5 | Directional only4 vs 1 rows | Directional only |
| Multimodal | 69.9 | 86.6 | Directional only2 vs 1 rows | Directional only |
| Reasoning | 64.4 | 93.6 | Not comparable1 vs 1 rows | Not comparable |
| Math | 57.5 | Not measured | Not comparable4 vs 0 rows | Not comparable |
| Multilingual | 85.7 | Not measured | Not comparable1 vs 0 rows | Not comparable |
| Instruction following | 69.5 | Not measured | Not comparable2 vs 0 rows | Not comparable |
Shape of the matched evidence
Only shared public evidence is shown. Sparse evidence stays a ruled list rather than being closed into a radar shape.
Too few matched category axes support a radar. The ruled list below shows only shared benchmark results; positions use each benchmark’s normalized display scale when available.
Terminal-Bench 2.0
Agentic
Claude Opus 4.5: 59.3%Sakana Fugu-Ultra: 82.1%Normalized gap 22.8Claude Opus 4.5 source Sakana Fugu-Ultra sourceCharXiv
Multimodal
Claude Opus 4.5: 68.5%Sakana Fugu-Ultra: 86.6%Normalized gap 18.1Claude Opus 4.5 source Sakana Fugu-Ultra sourceSWE-bench Pro
Coding
Claude Opus 4.5: 57.1%Sakana Fugu-Ultra: 73.7%Normalized gap 16.6Claude Opus 4.5 source Sakana Fugu-Ultra sourceGPQA
Knowledge
Claude Opus 4.5: 87%Sakana Fugu-Ultra: 95.5%Normalized gap 8.5Claude Opus 4.5 source Sakana Fugu-Ultra source
What each workload costs
Three fixed token mixes turn per-token rates into comparable decisions. Each scenario states context fit and whether cached input had to fall back to the published list-input rate.
Chat turn
1K fresh input + 500 output tokens
- Claude Opus 4.5
- $0.0175
- Fits in one request
- Sakana Fugu-Ultra
- API rate not published
- Fits in one request
Sakana Fugu-Ultra has no comparable published API token rate.
Repository review
50K fresh input + 3K output tokens
- Claude Opus 4.5
- $0.325
- Fits in one request
- Sakana Fugu-Ultra
- API rate not published
- Fits in one request
Sakana Fugu-Ultra has no comparable published API token rate.
Cache-heavy agent loop
200K cached + 20K fresh input + 10K output tokens
- Claude Opus 4.5
- $1.35
- Does not fit in one request
- Cached input priced at the published list-input rate
- Sakana Fugu-Ultra
- API rate not published
- Fits in one request
- Cached-input rate unavailable
Claude Opus 4.5 does not fit this workload in one request. Claude Opus 4.5 has no published cached-input rate, so cached tokens use its listed input rate. Sakana Fugu-Ultra has no comparable published API token rate.
Specification differences
Sourced differences are shown directly. Missing facts stay explicit instead of being inferred from a model name or family.
SpecificationClaude Opus 4.5Sakana Fugu-Ultra
Context window
Maximum documented context; output-token limits may be lower.
Claude Opus 4.5
200K
Sakana Fugu-Ultra
1M
API model ID
Claude Opus 4.5
Not sourced
Sakana Fugu-Ultra
Not sourced
Cached-input rate
A missing cached-input rate falls back to the listed input rate only in the stated workload estimate.
Claude Opus 4.5
Not published
Sakana Fugu-Ultra
No comparable hosted API rate
Documented inputs
Claude Opus 4.5
Not sourced
Sakana Fugu-Ultra
Not sourced
Documented outputs
Claude Opus 4.5
Not sourced
Sakana Fugu-Ultra
Not sourced
Provider availability
Claude Opus 4.5
Not sourced
Sakana Fugu-Ultra
Not sourced
Reasoning profile
Claude Opus 4.5
Non-Reasoning
Sakana Fugu-Ultra
Reasoning
Weight access
Claude Opus 4.5
Proprietary
Sakana Fugu-Ultra
Proprietary
License
Claude Opus 4.5
Proprietary
Sakana Fugu-Ultra
Proprietary
Release date
Claude Opus 4.5
2025-11-01
Sakana Fugu-Ultra
2026-06-22
If you already use one of these models
- Deployment change
- The models list different providers, so authentication, endpoint behavior, limits, and feature support may change.
- Quality signal
- At least one model is not scored in the current public ranking lane, so the page does not name an overall quality winner.
- Workload cost
- A complete comparable API-rate estimate is not available for both models.
- Context tradeoff
- Sakana Fugu-Ultra has the larger documented window (1M).
Run the same representative tasks against both endpoints before changing production traffic.
Benchmark evidence
The full public result ledger is available for audit without forcing a wide desktop table onto a phone.
Browse raw public benchmark evidence51 rows
Agentic
Terminal-Bench 2.0
Claude Opus 4.559.3%SourceSakana Fugu-Ultra82.1%SourceSakana Fugu-Ultra leads this result
OSWorld-Verified
Claude Opus 4.566.3%SourceSakana Fugu-Ultra—Not directly comparable
OSWorld
Claude Opus 4.566.3%SourceSakana Fugu-Ultra—Not directly comparable
Claw-Eval
Claude Opus 4.559.6%SourceSakana Fugu-Ultra—Not directly comparable
QwenClawBench
Claude Opus 4.552.3%SourceSakana Fugu-Ultra—Not directly comparable
τ³-bench results
Claude Opus 4.570.2%SourceSakana Fugu-Ultra—Not directly comparable
VITA-Bench
Claude Opus 4.523.3%SourceSakana Fugu-Ultra—Not directly comparable
DeepPlanning
Claude Opus 4.526.4%SourceSakana Fugu-Ultra—Not directly comparable
Toolathlon
Claude Opus 4.543.5%SourceSakana Fugu-Ultra—Not directly comparable
MCP Atlas
Claude Opus 4.542.3%SourceSakana Fugu-Ultra—Not directly comparable
MCP-Tasks
Claude Opus 4.571.8%SourceSakana Fugu-Ultra—Not directly comparable
WideResearch
Claude Opus 4.576.4%SourceSakana Fugu-Ultra—Not directly comparable
CyberGym
Claude Opus 4.550.6%SourceSakana Fugu-Ultra—Not directly comparable
Gert Labs
Claude Opus 4.564.23%SourceSakana Fugu-Ultra—Not directly comparable
JobBench
Claude Opus 4.532.3%SourceSakana Fugu-Ultra—Not directly comparable
Coding
SWE-bench Verified
Claude Opus 4.580.9%SourceSakana Fugu-Ultra—Not directly comparable
LiveCodeBench v6
Claude Opus 4.584.8%SourceSakana Fugu-Ultra93.2%SourceSakana Fugu-Ultra leads this result
SWE-bench Pro
Claude Opus 4.557.1%SourceSakana Fugu-Ultra73.7%SourceSakana Fugu-Ultra leads this result
SWE Multilingual
Claude Opus 4.577.5%SourceSakana Fugu-Ultra—Not directly comparable
NL2Repo
Claude Opus 4.543.2%SourceSakana Fugu-Ultra—Not directly comparable
Terminal-Bench 2.0
Claude Opus 4.5—Sakana Fugu-Ultra82.1%SourceNot directly comparable
LiveCodeBench Pro
Claude Opus 4.5—Sakana Fugu-Ultra90.8%SourceNot directly comparable
SciCode
Claude Opus 4.5—Sakana Fugu-Ultra58.7%SourceNot directly comparable
Reasoning
Knowledge
GPQA
Claude Opus 4.587%SourceSakana Fugu-Ultra95.5%SourceSakana Fugu-Ultra leads this result
SuperGPQA
Claude Opus 4.570.6%SourceSakana Fugu-Ultra—Not directly comparable
MMLU-Pro
Claude Opus 4.589.5%SourceSakana Fugu-Ultra—Not directly comparable
MMLU-Redux
Claude Opus 4.596.6%SourceSakana Fugu-Ultra—Not directly comparable
C-Eval
Claude Opus 4.592.2%SourceSakana Fugu-Ultra—Not directly comparable
HLE
Claude Opus 4.530.8%SourceSakana Fugu-Ultra—Not directly comparable
GPQA-D
Claude Opus 4.5—Sakana Fugu-Ultra95.5%SourceNot directly comparable
HLE w/o tools
Claude Opus 4.5—Sakana Fugu-Ultra50%SourceNot directly comparable
Math
AIME26
Claude Opus 4.595.1%SourceSakana Fugu-Ultra—Not directly comparable
HMMT Feb 2025
Claude Opus 4.592.9%SourceSakana Fugu-Ultra—Not directly comparable
HMMT Nov 2025
Claude Opus 4.593.3%SourceSakana Fugu-Ultra—Not directly comparable
HMMT Feb 2026
Claude Opus 4.585.3%SourceSakana Fugu-Ultra—Not directly comparable
MMAnswerBench
Claude Opus 4.584.0%SourceSakana Fugu-Ultra—Not directly comparable
FrontierMath v2 (Tiers 1-3)
Claude Opus 4.520.690%SourceSakana Fugu-Ultra—Not directly comparable
FrontierMath v2 (Tier 4)
Claude Opus 4.54.167%SourceSakana Fugu-Ultra—Not directly comparable
Multilingual
Multimodal
MMMU-Pro
Claude Opus 4.570.6%SourceSakana Fugu-Ultra—Not directly comparable
MathVision
Claude Opus 4.574.3%SourceSakana Fugu-Ultra—Not directly comparable
CharXiv
Claude Opus 4.568.5%SourceSakana Fugu-Ultra86.6%SourceSakana Fugu-Ultra leads this result
VideoMMMU
Claude Opus 4.584.4%SourceSakana Fugu-Ultra—Not directly comparable
ScreenSpot Pro
Claude Opus 4.545.7%SourceSakana Fugu-Ultra—Not directly comparable
V*
Claude Opus 4.567.0%SourceSakana Fugu-Ultra—Not directly comparable
Instruction following
Frequently asked questions
Which is better, Claude Opus 4.5 or Sakana Fugu-Ultra?
At least one model is not scored in the current public ranking lane, so the page does not name an overall quality winner. The page therefore keeps the decision tied to the specific documented workload.
Which is better for coding, Claude Opus 4.5 or Sakana Fugu-Ultra?
The current coding averages use different weighted benchmark sets, so BenchLM does not name a winner from them. Read the shared benchmark rows directly and test the models on the same task set.
Which is better for agentic tasks, Claude Opus 4.5 or Sakana Fugu-Ultra?
The current agentic tasks averages use different weighted benchmark sets, so BenchLM does not name a winner from them. Read the shared benchmark rows directly and test the models on the same task set.
Which costs less, Claude Opus 4.5 or Sakana Fugu-Ultra?
Both models do not have comparable published API token rates, so this page does not name a universal price winner.
Which has the larger context window, Claude Opus 4.5 or Sakana Fugu-Ultra?
Sakana Fugu-Ultra has the larger documented context window: 1M, compared with 200K.
Related comparisons
Last updated August 13, 2026
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