June 2026's biggest architectural debate: one frontier model vs orchestrated multi-agent APIs like Sakana Fugu.
Single-model advantages
Predictable latency, simpler debugging, direct vendor SLAs, and lower cognitive overhead. Claude Fable 5 or ChatGPT 5.6 alone wins for 80% of tasks.
Multi-agent advantages
Fugu learns coordination patterns — Thinker/Worker/Verifier roles across models. Excels when no single vendor tops every subtask (coding + math + verification).
Cost model
Fugu charges the top-tier model rate when multiple agents activate — never stacked fees. Fugu Ultra is fixed $5/$30. Compare against rolling your own router with LiteLLM.
Decision matrix
Startups: single model (DeepSeek V4 or GLM 5.2). Enterprise agents: Fugu for quality ceiling. Regulated: Claude Fable 5 for audit trail. Research: Fugu Ultra.
