VeruSAGE: A Study of Agent-Based Verification for Rust Systems
Chenyuan YangNatalie NeamtuChris HawblitzelJay LorchShan Lu
Demonstrates that tailored LLM agent architectures can automate formal verification of Rust system software, solving over 80% of tasks in a new 849-proof benchmark and completing more than 90% of real-world proof obligations left unfinished by human experts.
Formal software verification mathematically guarantees code correctness, which is critical for reliability-sensitive system infrastructure such as operating systems and storage engines. However, developing formal proofs manually using tools like Verus is labor-intensive and slow, creating a major engineering bottleneck. While artificial intelligence coding models generate software quickly, they lack correctness guarantees. Previous evaluations indicated that artificial intelligence struggled significantly on real-world system proofs, succeeding on 20% or fewer tasks. The article addresses this challenge by assessing whether advanced large language models, paired with specialized agent frameworks, can reliably automate formal correctness proofs for real-world systems written in Rust.
To conduct this evaluation, the researchers curated a new benchmark called VeruSAGE-Bench, extracting 849 standalone proof tasks across eight open-source, Verus-verified Rust systems spanning operating systems, memory allocators, and distributed controllers. The article compared two agent paradigms: a structured "hands-on" system called VeruSAGE—which guides models through dynamic planning, specialized reasoning agents, and history tracking—and a "hands-off" command-line interface approach that grants the model standard tools, verification libraries, and a cheat checker while allowing it to drive its own actions. Four state-of-the-art models were evaluated: o4-mini, GPT-5, Claude Sonnet 4, and Claude Sonnet 4.5.
The investigation produced several key findings. First, top-performing models demonstrated strong verification capabilities: Claude Sonnet 4.5 in the hands-off setting solved 81% of all benchmark tasks without human intervention, averaging 7.2 minutes per task. Second, the framework proved effective on incomplete human work, generating complete proofs for 23 out of 25 unfinished functions in the Atmosphere operating system and identifying five specification errors that human developers subsequently verified and fixed. Third, model capability dictated the optimal agent structure: smaller models like o4-mini doubled their success rate from 20% to 41% using the structured hands-on VeruSAGE framework, whereas frontier models performed best in the hands-off mode. Fourth, artificial intelligence proofs differed substantially from human proofs, averaging more than double the length (44 lines versus 17 lines) due to unnecessary intermediate assertions.
These findings indicate that integrating automated reasoning models into system development can substantially reduce the timeline and cost of building formally verified software. Because the underlying Verus tool mathematically verifies any generated proof, organizations can safely leverage artificial intelligence assistance without risking unverified or hallucinated logic entering production. Furthermore, model performance drops significantly when tasks involve large codebases, complex macro expansions, or inductive invariants in state machines, illustrating clear operational boundaries.
Organizations developing verified systems should incorporate tool-assisted coding agents directly into their verification workflows to assist engineers with modular proof functions and boilerplate lemmas. Standalone task extraction tools should be used to isolate functions before presenting them to models, as full repository contexts currently degrade performance and raise compute costs. Future work should focus on automating proof minimization to lower token costs, developing better support for macro expansions and state-machine invariants, and exploring full-lifecycle specification synthesis.
- Paper: SWE-agent: Agent-Computer Interfaces Enable Automated Software Engineering, John Yang et al. (2024). Learn how tailored Agent-Computer Interfaces enable LLM agents to interact iteratively with complex codebases via execution feedback and specialized tooling.
- Paper: LINC: A Neurosymbolic Approach for Logical Reasoning by Combining Language Models with First-Order Logic Provers, Theo Olausson et al. (2023). Understand neurosymbolic methodologies that pair LLM semantic generation with external formal theorem provers to establish verified correctness.
- Paper: Teaching Large Language Models to Self-Debug, Xinyun Chen et al. (2023). Explore how language models use compiler error messages and iterative self-debugging feedback loops to repair faulty code.
- Paper: MapCoder: Multi-Agent Code Generation for Competitive Problem Solving, Md. Ashraful Islam et al. (2024). Examine multi-agent architectures that divide software generation into distinct planning, generation, and verification roles.
- Paper: SWE-bench: Can Language Models Resolve Real-World GitHub Issues?, Carlos E. Jimenez et al. (2024). Review the benchmark foundation for evaluating LLM agents on multi-file code editing and real repository-level problem solving.
- Paper: LEAP: Supercharging LLMs for Formal Mathematics with Agentic Frameworks, Po-Nien Kung et al. (2026). See how agentic proof decomposition and compiler-in-the-loop validation extend to formal mathematical verification in interactive theorem provers like Lean.
- Paper: daVinci-Dev: Agent-native Mid-training for Software Engineering, Ji Zeng et al. (2026). Discover how foundation models can be pre-adapted for repository-scale agentic engineering and tool interaction via large-scale agent-native mid-training.
- Paper: GLM-5: from Vibe Coding to Agentic Engineering, GLM-5-Team et al. (2026). Explore the evolution from interactive prompting to autonomous agentic engineering across verifiable software development environments.
- Paper: FrogNano: Training a 4B Coding Agent via Online Task Synthesis, Minseon Kim et al. (2026). Investigate how reinforcement learning over synthesized coding tasks can train compact models to execute autonomous repository-level engineering workflows.
