TITLE
A DYNAMIC MULTI-AGENT SYSTEM FOR COVERAGE-BASED TESTBENCH SYNTHESIS IN SYSTEMVERILOG
AUTHOR(S)
Veljko Lončarević*, Mihailo Knežević, Olga Ristić, Vanja Luković, Sanja Antić
ABSTRACT
This work introduces a dynamic multi-agent framework for automated testbench generation in hardware verification, leveraging large language models (LLMs), cocotb, and Verilator. The system decomposes verification into specialized agent roles, including specification parsing, testbench synthesis, stimuli generation, coverage monitoring, and iterative refinement. Unlike naïve prompting, the closed-loop architecture ensures executable and reusable cocotb harnesses while systematically improving coverage. Experimental evaluation demonstrates
functional coverage of 93.7% (±2.1), a top-1 pass rate of 82.5%, and an average time-to-first-test of 1.4 hours, outperforming baseline LLM-driven methods and approaching recent automated UVM-based frameworks. The reduced refinement iterations further highlight the robustness and correctness of generated artifacts. While not yet achieving coverage saturation in domain-specific tasks, the modular agent design enables extensibility to larger RTL designs, heterogeneous simulators, and integration of advanced strategies such as reinforcement learning. These results demonstrate that LLM-driven multi-agent workflows provide a scalable and efficient methodology for reducing human effort in verification closure, establishing a promising direction for AI-assisted hardware verification.
DOI
How to cite this article:
Veljko Lončarević*, Mihailo Knežević, Olga Ristić, Vanja Luković, Sanja Antić, A DYNAMIC MULTI-AGENT SYSTEM FOR COVERAGE-BASED TESTBENCH SYNTHESIS IN SYSTEMVERILOG, UNITECH – SELECTED PAPERS - 2025