Mercury 2.5 Preview vs Fugu Ultra v2
Detailed technical comparison between Mercury 2.5 Preview (Inception AI) and Fugu Ultra v2 (Sakana AI). Review live API token pricing, context window capabilities, time-to-first-token latency, and verified benchmark scores side-by-side.
Comparison Snapshot
Fugu Ultra v2
1,000,000 tokensTie
Equal CapabilityTie
Equal SpeedMercury 2.5 Preview
$0.04 / MTokMercury 2.5 Preview
Mercury 2.5 Preview is an advanced artificial intelligence model engineered by Inception AI. Tailored for complex multi-step reasoning, programming synthesis, and extended document comprehension, Mercury 2.5 Preview represents a key architectural iteration in the Inception AI model family. First released in 2026-08-31, it serves enterprise developers, research teams, and autonomous system architects requiring strict instruction compliance. Featuring an input capacity of 260,000 tokens (approximately 347 words), Mercury 2.5 Preview processes multi-file code repositories, lengthy technical reports, and complex prompts in a single inference call.
Fugu Ultra v2
Fugu Ultra v2 is an advanced artificial intelligence model engineered by Sakana AI. Tailored for complex multi-step reasoning, programming synthesis, and extended document comprehension, Fugu Ultra v2 represents a key architectural iteration in the Sakana AI model family. First released in 2026-09-11, it serves enterprise developers, research teams, and autonomous system architects requiring strict instruction compliance. Featuring an input capacity of 1,000,000 tokens (approximately 1,333 words), Fugu Ultra v2 processes multi-file code repositories, lengthy technical reports, and complex prompts in a single inference call.
Technical Specifications
🏆 = Superior Spec| Specification | Mercury 2.5 Preview | Fugu Ultra v2 |
|---|---|---|
| Provider | Inception AI | Sakana AI |
| Context Window | 260,000 tokens | 1,000,000 tokens🏆 |
| Agent Suitability | Not yet benchmarked | Not yet benchmarked |
| Time to First Token (TTFT) | No public TTFT data | No public TTFT data |
| Deployment Model | managed api | managed api |
| Production Stability | Stable GA (est.) | Beta Access (est.) |
| API Available | Yes | Yes |
| Released Date | 2026-08-31 | 2026-09-11 |
API Pricing Comparison
Input Price per Million Tokens
Mercury 2.5 Preview
$0.04
Fugu Ultra v2
$5.00
Output Price per Million Tokens
Mercury 2.5 Preview
$0.15
Fugu Ultra v2
$30.00
💡 Cost Ratio: Mercury 2.5 Preview is 125.0x cheaper per input token than Fugu Ultra v2.
Want to test both models live?
Run side-by-side prompt benchmarks in our dynamic multi-model Sandbox. Compare execution speeds, latency metrics, and compute actual costs in real-time.
Benchmark Performance Metrics
Standardized Scores (0–100%)Scores show verified raw accuracy percentages across standardized AI evaluation suites. Higher bars indicate superior performance in that domain.
Mercury 2.5 Preview Quirks & Gotchas
No developer gotchas reported.
Fugu Ultra v2 Quirks & Gotchas
No developer gotchas reported.
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