# LEGO: An LLM Skill-Based Front-End Design Generation Platform

arXiv: https://arxiv.org/abs/2604.23355 · HTML: https://mlsanity.com/paper/2604.23355/

## Key facts

- No citing papers in the map yet (data through 14 Oct 2026).
- Builds on 19 of its 29 references that are in the map.
- First posted on arXiv 25 Apr 2026.

## Builds on (most cited first, 19 of 19)

- [VeriGen: A Large Language Model for Verilog Code Generation](https://mlsanity.com/paper/2308.00708/) (2023)
- [ChipNeMo: Domain-Adapted LLMs for Chip Design](https://mlsanity.com/paper/2311.00176/) (2023)
- [RTLLM: An Open-Source Benchmark for Design RTL Generation with Large Language Model](https://mlsanity.com/paper/2308.05345/) (2023)
- [RTLFixer: Automatically Fixing RTL Syntax Errors with Large Language Models](https://mlsanity.com/paper/2311.16543/) (2023)
- [AutoChip: Automating HDL Generation Using LLM Feedback](https://mlsanity.com/paper/2311.04887/) (2023)
- [VerilogCoder: Autonomous Verilog Coding Agents with Graph-based Planning and Abstract Syntax Tree (AST)-based Waveform Tracing Tool](https://mlsanity.com/paper/2408.08927/) (2024)
- [OriGen:Enhancing RTL Code Generation with Code-to-Code Augmentation and Self-Reflection](https://mlsanity.com/paper/2407.16237/) (2024)
- [AutoBench: Automatic Testbench Generation and Evaluation Using LLMs for HDL Design](https://mlsanity.com/paper/2407.03891/) (2024)
- [Towards LLM-Powered Verilog RTL Assistant: Self-Verification and Self-Correction](https://mlsanity.com/paper/2406.00115/) (2024)
- [CodeV: Empowering LLMs with HDL Generation through Multi-Level Summarization](https://mlsanity.com/paper/2407.10424/) (2024)
- [AutoVCoder: A Systematic Framework for Automated Verilog Code Generation using LLMs](https://mlsanity.com/paper/2407.18333/) (2024)
- [OpenLLM-RTL: Open Dataset and Benchmark for LLM-Aided Design RTL Generation](https://mlsanity.com/paper/2503.15112/) (2025)
- [Spec2RTL-Agent: Automated Hardware Code Generation from Complex Specifications Using LLM Agent Systems](https://mlsanity.com/paper/2506.13905/) (2025)
- [HiVeGen -- Hierarchical LLM-based Verilog Generation for Scalable Chip Design](https://mlsanity.com/paper/2412.05393/) (2024)
- [VeriMind: Agentic LLM for Automated Verilog Generation with a Novel Evaluation Metric](https://mlsanity.com/paper/2503.16514/) (2025)
- [TuRTLe: A Unified Evaluation of LLMs for RTL Generation](https://mlsanity.com/paper/2504.01986/) (2025)
- [Understanding and Mitigating Errors of LLM-Generated RTL Code](https://mlsanity.com/paper/2508.05266/) (2025)
- [HDL-GPT: High-Quality HDL is All You Need](https://mlsanity.com/paper/2407.18423/) (2024)
- [BRIDGES: Bridging Graph Modality and Large Language Models within EDA Tasks](https://mlsanity.com/paper/2504.05180/) (2025)

## Abstract (arXiv)

Existing LLM-based EDA agents are often isolated task-specific systems. This leads to repeated engineering effort and limited reuse of successful design and debugging strategies. We present LEGO, a unified skill-based platform for front-end design generation. It decomposes the digital front-end flow into six independent steps and represents every agent capability as a standardized composable circuit skill within a plug-and-play architecture. To build this skill library, we survey more than 100 papers, select 11 representative open-source projects, and extract 42 executable circuit skills within a six-step finite state machine formulation. Circuit Skill Builder automates skill extraction with linear scalability. Agent Skill RAG achieves submillisecond retrieval without relying on embedding models. Empirical evaluation on a hard subset of 41 VerilogEval v2 problems that gpt-5.2-codex fails to solve under extra-high reasoning effort shows that individual circuit skills constructed within LEGO raise Pass@1 from 0.000 to 0.805. This is an 80.5% gain over the baseline. Cross-project skill compositions also reach 0.805 Pass@1. They outperform hierarchy-verilog by 14.6% and VerilogCoder by 2.5%. They also match MAGE. These results show that modular skill composition supports both effective and flexible RTL design automation. The LEGO platform and all circuit skills are publicly available at GitHub: https://github.com/loujc/LEGO-An-LLM-Skill-Based-Front-End-Design-Generation-Platform