SWE-2 vs. SWE-1.7

SWE-2 is Cognition’s coding model for software engineering agents, developed to improve the balance between capability, reasoning cost, and execution efficiency. The model is post-trained from Kimi K3, a multi-trillion-parameter model that had already received extensive reinforcement learning for agentic coding. Cognition further trained SWE-2 with a reinforcement learning algorithm that optimizes several reasoning-effort levels during a single training run. These effort levels let users trade off speed and cost against deeper planning, codebase exploration, and verification for more difficult assignments. SWE-2 is designed to reduce the over-exploration seen in earlier models by identifying relevant files and implementation paths more quickly. Its software engineering abilities include repository analysis, code writing and editing, debugging, testing, build and lint workflows, terminal tasks, and verification of completed work. The model places additional emphasis on writing end-to-end tests, catching edge cases and regressions, and gathering evidence instead of simply accepting assumptions in a prompt. Cognition’s training approach also uses cost penalties tied to the model’s performance frontier, length-weighted reward baselines, speculative decoding improvements, low-precision inference techniques, and expanded reinforcement learning data. Training data includes more diverse repositories, additional instruction-following requirements, and iterative verifier improvements designed to reduce reward hacking and false validation. SWE-2 is benchmarked against models such as GPT-6 Astra, GPT-5.6 Sol, Fable 5.1, Grok 4.6, and Kimi K3, with Cognition positioning it around strong coding performance at substantially lower cost. SWE-2 is intended for use across Cognition’s Devin ecosystem, including Desktop and CLI, with rollout to Devin Web and Fusion.

SWE-1.7 is a frontier software engineering model from Cognition built for advanced coding agents and long-horizon development workflows. It is designed to deliver strong coding intelligence at a fraction of the cost of some leading frontier alternatives, improving the cost-performance balance for real software engineering work. The model is trained from a Kimi K2.7 base and further improved through Cognition’s reinforcement learning pipeline, showing that additional post-training can still produce major capability gains. SWE-1.7 is optimized for tasks such as bug fixing, feature implementation, code migrations, terminal-based workflows, multilingual software engineering, large codebase navigation, and end-to-end validation. It performs especially well on longer asynchronous tasks where an AI agent needs to gather context, inspect files, test hypotheses, make changes, and verify results over an extended period. Cognition trained the model with infrastructure improvements that preserve entropy, stabilize training, support multi-cluster reinforcement learning, and improve fault tolerance across large distributed runs. The training process also focused heavily on data quality, using automated execution tests, verifier quality checks, reward-hacking prevention, and task filtering to create stronger learning signals. SWE-1.7 includes self-compaction, allowing it to summarize its working state and continue long projects even when tasks exceed the raw context window. It also uses an alternating length penalty to encourage concise reasoning on easier tasks while maintaining deeper exploration when a problem requires it. In practice, the model tends to explore codebases carefully, read relevant files, search for hidden requirements, test edge cases, and experiment before deciding how to implement a fix. Available in Devin across web, desktop, and CLI via Cerebras, SWE-1.7 gives engineering teams a powerful model for running scalable, cost-efficient coding agents.