PatchOptic: Verified structured updates for shared-state LLM workflows

Agentic LLM workflows often manipulate shared structured state, but limited context windows force progressive disclosure—showing only relevant fragments per step. Existing methods like RAG, AST queries, or grep handle reads but lack a formal contract for when local writes are globally valid. PatchOptic, introduced by Bai and Cai, borrows from optics theory (bidirectional accessors) to define projected reads, authorized write regions, and patch-source regions. The system enforces runtime verification, blocking violations before commit and rejecting compromised patches using hidden sources.

Evaluated on PatchBench (46 cases across domains), PatchOptic demonstrated reduced reported leakage and token costs while maintaining accepted-output quality under the strong actor test. Key contributions include a path-level footprint for delegation, sub-workflow composition, and static certificates for reordering independent steps. This provides a principled solution for building reliable multi-step LLM agents that operate on shared state without sacrificing correctness or efficiency.