Sakana's Fugu Ultra v1.1 claims to beat Claude's Fable 5 without using it

Fugu Ultra v1.1 represents Sakana's attempt to position AI routing—intelligent distribution of queries across multiple models—as a competitive alternative to building or fine-tuning a single large model. The claimed 7.9-point performance gain over v1.0, particularly on ProgramBench and TerminalBench 2.1, suggests optimization is occurring; however, the lack of independent verification is a significant caveat. The fact that Sakana claims v1.1 outperforms Fable 5 without including it in the pool could indicate either genuine architectural efficiency or that the benchmarks themselves may not be representative of real-world use.

The first Fugu version encountered skepticism due to high token usage, slow response times, and disappointing results—issues that a 7.9-point gain may address, but only if verified externally. The addition of a Claude Code-compatible endpoint signals Sakana's intent to integrate more deeply into developer workflows. The two-week evaluation window for adding new models to the pool suggests Sakana has a process to keep Fugu current as new models emerge, though this also means the pool is not static and claims about v1.1's performance may shift as models are added or removed.