Interface-Led Architecture (ILA): A Software Development Methodology for the AI Era, Validated by the AIKernel Execution Model

This technical report proposes Interface-Led Architecture (ILA), a software development methodology for the age of AI-assisted implementation. ILA builds software from interfaces, contracts, and responsibility boundaries rather than from implementation-first code. The paper defines interfaces as responsibility, contract, implementation replacement, AI generation, testing, and governance boundaries. The paper also positions AIKernel as a validation environment for ILA. AIKernel provides Pipeline, Context, ROM, Contract, Provider, ReplayLog, and deterministic execution boundaries. ROM externalizes human design intent and contracts as reusable knowledge, while ReplayLog provides a reproducibility foundation for verifying that AI-driven implementation modifications do not break existing contracts. This Zenodo package includes both the English manuscript and the Japanese manuscript.