Kimi K3 vs Claude Fable 5 on DeepSWE: Cost and Coding

This post provides a detailed comparison of Kimi K3 and Claude Fable 5 on the DeepSWE benchmark, focusing on performance metrics (pass@1, pass@2, pass@4), cost per solved task, and language-specific performance. It highlights Kimi K3's competitive performance, particularly at higher pass@k values, and its significant cost advantage (2.8x more solved tasks per dollar). The post also notes the high correlation in task success and failure between the two models, suggesting limited diversity gains when pairing them. It concludes that Kimi K3 is a rational default for its balance of reach and cost, especially for retry-tolerant agent work.