Cognition turned an open model into a coding beast. But it won't release the weights.

Released Wednesday, SWE-2 Flash costs one-fifth as much as Cognition's larger SWE-2 model and generates tokens around three times faster, according to the company. Built on Thinking Machines Lab's open weight Inkling-Small, the new model comes with a catch: Cognition is keeping its weights private, citing cybersecurity concerns. CultOfAI, an AI commentary account on X, calls mid-training "a practical way to turn a weak open base into a usable agent model," though the same account cautions that the figures are Cognition's own rather than independently verified. Cheaper, faster, still trailing Flash doesn't keep pace with the larger model on every test, coming within a hair on SWE-Bench Pro v2 Hard at 89.9% to SWE-2's 90.6% but trailing on DeepSWE 1.1 and Terminal-Bench 4.0, while competitors including Claude Haiku 5.5 and DeepSeek V4.1 Flash outscore it on several benchmarks.