rtl-bug-repro

rtl-bug-repro is a skill for Claude Code from babyworm/rtl-agent-team. It costs 38 tokens per session (1,928 once invoked), scanned A, original, MIT.

A debugging workflow that recreates an RTL failure with a small testbench and uses waveform differences to find its cause.

In plain words
What is it for?
Use it with a failure log or simulation waveform to create a focused reproduction and document the root cause.
Why use it?
A minimal reproduction is easier and faster to inspect than a full regression run, making it easier to isolate the failing module.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Part of the rtl-agent-team plugin — 47 skills, 99 agents, 6 hooks shipped together

Good fit Use it with a failure log or simulation waveform to create a focused reproduction and document the root cause.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/babyworm/rtl-agent-team/rtl-bug-repro
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add babyworm/rtl-agent-team --skill rtl-bug-repro
Clone the repo
git clone --depth 1 https://github.com/babyworm/rtl-agent-team

Made for: Claude Code.

Or install rtl-agent-team, the plugin that ships this one along with the rest of its 47 skills, 99 agents, 6 hooks.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for rtl-bug-repro

README.md
[![agentmods](https://agentmods.dev/badge/skills/babyworm/rtl-agent-team/rtl-bug-repro/github.svg)](https://agentmods.dev/skills/babyworm/rtl-agent-team/rtl-bug-repro)
Your own site
<a href="https://agentmods.dev/skills/babyworm/rtl-agent-team/rtl-bug-repro"><img src="https://agentmods.dev/badge/skills/babyworm/rtl-agent-team/rtl-bug-repro/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for rtl-bug-repro

Your own site · 80×15
<a href="https://agentmods.dev/skills/babyworm/rtl-agent-team/rtl-bug-repro"><img src="https://agentmods.dev/badge/skills/babyworm/rtl-agent-team/rtl-bug-repro.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 38 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,928 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high Memory Poisoning · line 57
    Skill manipulates agent memory, state, or stored context. Memory corruption can alter personality, override safety rules, or cause unpredictable behavior.
    Fix: Protect agent memory and state from modification by untrusted content. Use read-only memory for critical instructions and validate all state changes.
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00038 $0.01928
Opus 5 $0.00019 $0.00964
Sonnet 5 $0.00008 $0.00386
Haiku 4.5 $0.00004 $0.00193

Measured 7d ago against content hash 433b927b311f, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

rtl-bug-repro scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 7d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/vcd_diff.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/rtl-bug-repro/SKILL.md · 117 lines

How it starts

The opening of the file, as written. The whole thing — 117 lines — stays where its author put it; the contents beside it link to each section on GitHub.

<Use_When>

  • A bug has been reported with a failure log or a failing test case.
  • A simulation failure needs root cause analysis before an RTL fix is attempted.
  • A regression failure needs isolation to a specific module. </Use_When>

<Do_Not_Use_When>

  • The bug is in the testbench, not in RTL — fix the testbench directly.
  • The root cause is already known — proceed to RTL fix.
  • The bug is a synthesis issue — use rtl-synth-check instead. </Do_Not_Use_When>

<Why_This_Exists> Debugging without a minimal reproduction wastes time. Waveform analysis on the full regression is slow; a targeted minimal TB isolates the failure in minutes. root_cause.md documents the finding for the RTL engineer making the fix, and the repro TB can be added directly to the regression suite. </Why_This_Exists>

Prerequisites

  • A failure log or failing .vcd/.fst waveform from a previous simulation run.
  • RTL source for the suspected module under rtl/**/*.sv.

If prerequisites are missing: WARNING — recommend running the failing regression test first to obtain a waveform. Proceed with available artifacts; the orchestrator adapts scope.

<Responsibility_Boundary>

  • Scripts handle deterministic waveform work: vcd_diff.py identifies the exact divergence cycle and signal path between two VCD files.
  • LLM handles interpretive content: root cause hypothesis, signal trace narrative, suspected RTL location, and minimal stimulus design.
  • Contract surface: root_cause.md structure documented in references/bug-repro-conventions.md. </Responsibility_Boundary>

Apply steps 1-6 to every bug ID requested — do not stop after the first.

<Tool_Usage> Waveform analysis (when no golden VCD for diff):

Task(subagent_type="rtl-agent-team:waveform-analyzer",
     prompt="Analyze sim/regression/test_cabac_fail.vcd. Find first divergence between actual and expected output. Identify originating module and signal path. Port signals use i_/o_ prefixes, clocks are {domain}_clk, resets are {domain}_rst_n.")

Read the full file on GitHub · 117 lines

Files

What ships with it

8 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 7d ago First seen · 117 lines · 38 tokens per session scan A 433b927b311f

Subscribe to this mod's changes

rtl-bug-repro is a skill published in the GitHub repository babyworm/rtl-agent-team (51 stars, last pushed 18d ago), licensed MIT. It adds 38 tokens to every session and 1,928 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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