Cognition's Devin Fusion routes coding work between two models to cut cost
Devin Fusion: Frontier Performance at 60% Lower Cost
AISummary
Cognition has released a preview of Devin Fusion, a multi-model harness that runs a frontier main agent alongside a cheaper sidekick agent. On FrontierCode 1.1 Extended, the company reports scores near frontier models at up to 60% lower cost per task, and 41% lower cost when paired with Fable 5, which access was suspended from June 12, 2026.
AIWhy it matters
The post explains a sidekick architecture with cached persistent contexts, which contrasts with advisor-style tools and shows how cost cuts depend on the main model's delegation behavior.
Source: Cognition Blog (Devin, Windsurf) · cognition.com