An arXiv paper introduces Dev-Primitives, an abstraction that pairs each repository artifact — source files, configs, tests, dependencies — with a resident LLM, giving it an agent-native interface for natural-language reasoning, inter-component communication and localized self-modification. Built on top of it, the HERMES harness-engineering framework activates these primitives at repository scale via dependency-aware dynamic activation and a bug-diagnosis mechanism that maps execution evidence back to the components needing revision. The authors report HERMES beats matched baseline harnesses by 12.4% on average across four software engineering benchmarks, stays within 4.5% of a homogeneous GPT-5.6 Sol configuration even with Qwen3-8B Dev-Primitives, and cuts inference cost by 26.2% on Terminal-Bench 4.0.