Clover: A Neural-Symbolic Agentic Harness with Stochastic Tree-of-Thoughts for Verified RTL Repair

Fuente: arXiv
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Main Authors: Luo, Zizhang, Xu, Yansong, Guo, Runlin, Cui, Fan, Zhou, Kexing, Xia, Mile, Hou, Hongyuan, Luo, Yuhao, Liang, Yun
Format: Preprint
Published: 2026
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author Luo, Zizhang
Xu, Yansong
Guo, Runlin
Cui, Fan
Zhou, Kexing
Xia, Mile
Hou, Hongyuan
Luo, Yuhao
Liang, Yun
author_facet Luo, Zizhang
Xu, Yansong
Guo, Runlin
Cui, Fan
Zhou, Kexing
Xia, Mile
Hou, Hongyuan
Luo, Yuhao
Liang, Yun
contents RTL program repair remains a critical bottleneck in hardware design and verification. Traditional automatic program repair (APR) methods rely on predefined templates and synthesis, limiting their bug coverage. Large language models (LLMs) and coding agents based on them offer flexibility but suffer from randomness and context corruption when handling long RTL code and waveforms. We present Clover, a neural-symbolic agentic harness that orchestrates RTL repair as a structured search over code manipulations to explore a validated solution for the bug. Recognizing that different repair operations favor distinct strategies, Clover dynamically dispatches tasks to specialized LLM agents or symbolic solvers. At its core, Clover introduces stochastic tree-of-thoughts, a test-time scaling mechanism that manages the main agent's context as a search tree, balancing exploration and exploitation for reliable outcomes. An RTL-specific toolbox further empowers agents to interact with the debugging environment. Evaluated on the RTL-repair benchmark, Clover fixes 96.8% of bugs within a fixed time limit, covering 94% and 63% more bugs than both pure traditional and LLM-based baselines, respectively, while achieving an average pass@1 rate of 87.5%, demonstrating high reliability and effectiveness.
format Preprint
id arxiv_https___arxiv_org_abs_2604_17288
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Clover: A Neural-Symbolic Agentic Harness with Stochastic Tree-of-Thoughts for Verified RTL Repair
Luo, Zizhang
Xu, Yansong
Guo, Runlin
Cui, Fan
Zhou, Kexing
Xia, Mile
Hou, Hongyuan
Luo, Yuhao
Liang, Yun
Hardware Architecture
Artificial Intelligence
I.2.2; B.5.2; D.2.5
RTL program repair remains a critical bottleneck in hardware design and verification. Traditional automatic program repair (APR) methods rely on predefined templates and synthesis, limiting their bug coverage. Large language models (LLMs) and coding agents based on them offer flexibility but suffer from randomness and context corruption when handling long RTL code and waveforms. We present Clover, a neural-symbolic agentic harness that orchestrates RTL repair as a structured search over code manipulations to explore a validated solution for the bug. Recognizing that different repair operations favor distinct strategies, Clover dynamically dispatches tasks to specialized LLM agents or symbolic solvers. At its core, Clover introduces stochastic tree-of-thoughts, a test-time scaling mechanism that manages the main agent's context as a search tree, balancing exploration and exploitation for reliable outcomes. An RTL-specific toolbox further empowers agents to interact with the debugging environment. Evaluated on the RTL-repair benchmark, Clover fixes 96.8% of bugs within a fixed time limit, covering 94% and 63% more bugs than both pure traditional and LLM-based baselines, respectively, while achieving an average pass@1 rate of 87.5%, demonstrating high reliability and effectiveness.
title Clover: A Neural-Symbolic Agentic Harness with Stochastic Tree-of-Thoughts for Verified RTL Repair
topic Hardware Architecture
Artificial Intelligence
I.2.2; B.5.2; D.2.5
url https://arxiv.org/abs/2604.17288