Role-Isolated State Partitions and Asymmetric Verification Gates for Multi-Agent Software Synthesis

Autonomous multi-agent systems driven by Large Language Models (LLMs) are increasingly applied to complex software engineering tasks. However, current implementations relying on monolithic conversational contexts or unconstrained peer-to-peer topologies exhibit three recurring failure modes: context pollution, concurrent filesystem race conditions, and self-grading verification bias. When multiple agents modify an active codebase simultaneously, mutual read-write contention over repository index files and shared type definitions produces irrecoverable divergence and phantom test passes. This technical note presents a deterministic orchestration architecture grounded in role-isolated state partitions and asymmetric verification gates. By partitioning the codebase filesystem into mathematically disjoint write sets assigned to specialized roles, concurrent write contention is reduced to zero. In addition, an independent dual-stage verification layer separating build execution from semantic audit eliminates developer self-evaluation bias. An empirical evaluation across 48 software modification tasks demonstrated that this architecture eliminated write conflicts (18.7% to 0.0%), lowered post-build defect rates from 22.9% to 2.1%, and reduced mean context token consumption by 31.4% compared to monolithic architectures.