DeepSeek V4 Pro 0813 vs Claude Fable 5 on DeepSWE: Cost, Coding, and Routing

Fable wins the first attempt, Pro wins every attempt after, and the cheapest path is to use both.

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Run DeepSeek V4 Pro 0813 first, escalate to Claude Fable 5 only when it fails. That cascade solves 82.7% of DeepSWE tasks at \$8.28 each. Fable alone solves 69.7% at \$21.63. Thirteen points better, 62% cheaper.

In our DeepSeek V4 Pro 0813 vs Claude Fable 5 comparison on DeepSWE, a benchmark that tests a model's software engineering ability across many task types and programming languages, the two models sit at opposite ends of the price sheet. Claude Fable 5 is the most expensive rollout on the DeepSWE board. DeepSeek V4 Pro 0813 is one of the cheapest. Fable is seven points more accurate on the first try and costs ninety times as much per rollout, so the real question is not which model is better, but what that 90x premium actually buys and when it is worth paying.

DeepSeek V4 Pro 0813 vs Claude Fable 5 at a glance

We ran DeepSeek V4 Pro 0813 (max) against Claude Fable 5 (max) on all 113 DeepSWE tasks, four trials each, from the published per-trial records: 904 rollouts in total (452 each). Fable is the expensive craftsman; Pro is the value outlier. The two also disagree more than any other pairing in this set, which turns out to be the most interesting thing about them. Every figure below comes from this run, so it can differ from other public DeepSeek V4 Pro 0813 vs Claude Fable 5 scorecards.