Compare SWE-1.5 vs. SWE-2

Cognition has unveiled SWE-1.5, the newest agent-model specifically designed for software engineering, featuring an expansive "frontier-size" architecture composed of hundreds of billions of parameters and an end-to-end optimization (encompassing the model, inference engine, and agent harness) that enhances both speed and intelligence. This model showcases nearly state-of-the-art coding capabilities and establishes a new standard for latency, achieving inference speeds of up to 950 tokens per second, which is approximately six times quicker than its predecessor, Haiku 4.5, and thirteen times faster than Sonnet 4.5. Trained through extensive reinforcement learning in realistic coding-agent environments that incorporate multi-turn workflows, unit tests, and quality assessments, SWE-1.5 also leverages integrated software tools and high-performance hardware, including thousands of GB200 NVL72 chips paired with a custom hypervisor infrastructure. Furthermore, its innovative architecture allows for more effective handling of complex coding tasks and improves overall productivity for software development teams. This combination of speed, efficiency, and intelligent design positions SWE-1.5 as a game changer in the realm of coding models.

SWE-2 is a software engineering model from Cognition built for agentic coding tasks that require strong performance at lower computational and monetary cost. It is post-trained from the Kimi K3 base model and extends Cognition’s earlier SWE-1.7 training approach with a new reinforcement learning method for jointly optimizing multiple reasoning-effort settings. Medium, high, and maximum effort modes provide different tradeoffs between speed, cost, exploration, and verification depending on task complexity. The model is trained to inspect only the parts of a codebase that are likely to matter, helping it reach implementation faster and reduce unnecessary exploration. SWE-2 can generate and modify code, run tests, analyze repositories, work through terminal tasks, and verify whether implementations satisfy user requirements. Cognition also reports improvements in end-to-end test creation, regression detection, instruction following, and re-deriving conclusions when challenged. Its training process incorporates cost-aware rewards, length-weighted reward baselines, expanded reinforcement learning environments, and hardened verifiers intended to improve both efficiency and reliability. SWE-2 is positioned as a cost-efficient alternative to larger frontier coding models while remaining competitive on software engineering benchmarks such as FrontierCode, DeepSWE, and Terminal-Bench. The model is available in Devin Desktop and Devin CLI and is being introduced to additional Cognition products including Devin Web and Fusion.