manage system state

Traditional typestate systems struggle to capture quantitative constraints—such as quorum requirements—and concurrent I/O behaviors inherent in distributed protocols, and they lack resilience to runtime network failures. This work proposes a probabilistic runtime verification approach that integrates mutable internal state, hybrid session mechanisms, and expected action ratios into an extended typestate model. The resulting framework enables dynamic modeling and monitoring of critical properties like concurrent message exchange and quorum satisfaction. Evaluated on commit and voting-based consensus protocols, the method effectively detects runtime behavioral deviations, significantly enhancing the expressiveness and practical applicability of typestate reasoning in distributed systems.

This paper addresses the challenges of weak consistency and high maintenance costs in software platform architecture evolution. We propose symmetry as a foundational architectural design principle: by identifying structural invariants—such as interfaces and behavioral specifications—under transformations (e.g., module replacement, deployment migration), we construct a formal architectural model incorporating symmetry constraints. Methodologically, we integrate group-theoretic modeling with structural analysis to quantitatively characterize the intrinsic relationship between architectural robustness and symmetry. Empirical and theoretical results demonstrate that symmetry constraints significantly improve system-wide consistency, reduce evolutionary complexity, and enhance scalability, reliability, and maintainability. To our knowledge, this work establishes the first systematic theoretical framework and formal modeling methodology for software architecture symmetry, offering a novel paradigm for designing resilient, evolvable platforms.

To address communication-intensive session programming, this paper proposes a novel session type system supporting explicit commit, rollback, and abort operations. To prevent illegal cross-participant state restoration, it introduces—within the session types framework—the first statically decidable rollback compliance check, ensuring rollbacks affect only locally accessed states and never violate inter-participant boundaries. Building on session type theory, the authors extend the session language and integrate MAUDE for design-time, type-level verification. They formally prove that the system satisfies error-freedom and progress properties. The core contributions are: (i) a safe and controllable rollback semantics grounded in session types; (ii) static enforcement of cross-participant isolation during rollback; and (iii) verifiable session recovery behavior, enabling rigorous reasoning about fault-tolerant distributed protocols.

Existing workflow persistence frameworks lack precise, machine-verifiable recovery semantic contracts, often resulting in inconsistent post-crash behaviors or violations of their own guarantees. This work proposes RESUME CONTRACT, which formally specifies six core recovery properties and employs TLA+ modeling alongside Verus verification to establish their independence and correctness. Leveraging a deterministic testing framework, the authors empirically evaluate prominent systems across a state space of 7.4 million configurations, uncovering semantic flaws in widely used frameworks such as LangGraph and CrewAI. Guided by these findings, they develop REMIT, a reference implementation that effectively addresses critical issues including fork semantics, recovery validity, and cross-process duplicate consumption, and has already been successfully deployed.

This work addresses the challenges of transferability and computational feasibility in discrete abstraction for symbolic model checking of cyber-physical systems by proposing a conservatism-first, four-step modular workflow to construct finite-state abstractions of closed-loop dynamical systems. The approach integrates state partitioning, conservative transition construction, spurious behavior elimination, and specification semantics lifting, enabling composable and replaceable subroutine design. Transition relations are built using axis-aligned bounding boxes, polyhedra, and sampling with PAC coverage certificates, combined with certified erasure and counterexample-guided refinement. Reliable lifting of LTL specifications is achieved through may–must semantics. Evaluation across three case studies demonstrates that the workflow effectively balances abstraction accuracy and verification efficiency while clearly revealing the impact of different design choices on the outcomes.

Existing runtime harnesses for programming agents suffer from either oversimplification or excessive complexity, lacking a clear and concise architectural paradigm. This work proposes a harness design centered on the request lifecycle, explicitly delineating three core boundaries: model, execution, and state. By orchestrating a structured sequence—comprising context construction, model decision-making, environmental action, observation feedback, and state continuation—the design enables cross-request state persistence and continual self-improvement through bootstrapping. We implement this paradigm in Coderlet, an open-source prototype system, demonstrating its efficacy in coordinating code generation, environment interaction, and state management. The resulting framework provides a scalable foundation for building high-performance programming agents.