Cognition ships SWE-2, a coding model post-trained from the open Kimi K3 base

Cognition released SWE-2 on September 10, a coding-agent model post-trained from Kimi K3, Moonshot AI’s open 2.8-trillion-parameter base. It approaches Fable 5.1 on coding benchmarks at a claimed 64% lower cost, but collapses on Terminal-Bench 4 — the signal that its gains do not generalize to the hardest test.