HERMES harness lifts GPT-5.6 Sol repository migration from 6.5% to 31.0%

A paper introduces HERMES, a harness that pairs each repository component with a resident LLM and uses dependency-aware activation and failure diagnosis.

With the same model and effort setting, GPT-5.6 Sol's whole-repository migration score rose from 6.5% to 31.0% when Codex was replaced by HERMES. Across four software engineering benchmarks, HERMES beats matched baseline harnesses by 12.4 points on average, and Qwen3-8B components come within 4.5 points of an all-GPT-5.6 Sol setup while cutting Terminal-Bench 4.0 inference cost by 26.2%.