varch

varch is a skill for Claude Code from phamcuong21478/rtl-skills. It costs 30 tokens per session (3,313 once invoked), scanned A, original, Apache-2.0.

An RTL architecture tool for breaking a complete hardware requirement into smaller modules, defining how they connect, and documenting the planned structure.

In plain words
What is it for?
Use it to create an architecture document, one Markdown requirement file per submodule, and a top-level Verilog integration skeleton.
Why use it?
It turns a broad IP description into separate, actionable requirements and an integration starting point. The architecture document remains the source of truth when the design is regenerated.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter.

Good fit Use it to create an architecture document, one Markdown requirement file per submodule, and a top-level Verilog integration skeleton.

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Install with agentmods
npx agentmods add skills/phamcuong21478/rtl-skills/varch
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 phamcuong21478/rtl-skills --skill varch
Clone the repo
git clone --depth 1 https://github.com/phamcuong21478/rtl-skills

Made for: Claude Code.

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 varch

README.md
[![agentmods](https://agentmods.dev/badge/skills/phamcuong21478/rtl-skills/varch/github.svg)](https://agentmods.dev/skills/phamcuong21478/rtl-skills/varch)
Your own site
<a href="https://agentmods.dev/skills/phamcuong21478/rtl-skills/varch"><img src="https://agentmods.dev/badge/skills/phamcuong21478/rtl-skills/varch/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 varch

Your own site · 80×15
<a href="https://agentmods.dev/skills/phamcuong21478/rtl-skills/varch"><img src="https://agentmods.dev/badge/skills/phamcuong21478/rtl-skills/varch.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 30 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,313 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.
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 $0.00030 $0.03313
Opus 5 $0.00015 $0.01656
Sonnet 5 $0.00006 $0.00663
Haiku 4.5 $0.00003 $0.00331

Measured 11d ago against content hash 58c66328ab07, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

varch 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 11d ago.

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/varch/SKILL.md · 239 lines

How it starts

The opening of the file, as written. The whole thing — 239 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Verilog Architect

Overview

This guide defines the workflow for decomposing a top-level IP requirement into submodules, defining their interfaces, and capturing the result in an architecture document that drives the per-submodule requirement files (ready for vdesign) and the top-level skeleton.

The input is a top-level IP requirement .md file. The outputs are:

  1. An architecture document ./ddoc/<ip>_arch.md — the canonical structural source (decomposition, block diagram, interface table, parameter propagation map). This is the one file the user edits to change the architecture and re-run.
  2. One requirement .md file per submodule in ./ddoc/, derived from the architecture document
  3. A top-level integration skeleton in ./rtl/, derived from the architecture document

varch is idempotent and architecture-document-driven: on a re-run, ./ddoc/<ip>_arch.md is the source of truth and the requirement files and skeleton are regenerated from it (see Step 6). On the first run the document does not exist yet, so Steps 1–2 create it.

Re-run: if ./ddoc/<ip>_arch.md already exists, it is authoritative. Read it instead of re-deriving the decomposition from scratch, apply whatever the user changed in it (or asks for), then go to Step 6 (regenerate), which ends in the Step 5 self-check. Steps 1–4 below describe the first run that builds the document.

Step 1 - Analyze Requirements and Propose Decomposition

Read the top-level IP requirement .md file and extract the design intent.

Before proposing a new decomposition, check ./lib for any existing library modules that already cover part of the required functionality. Read each candidate's <module>.md documentation to understand its interface and behaviour — the docs follow the ModuleDocContract and are usable without reading the RTL, so there is no need to run vexplain. Only fall back to reading the source (or vexplain) if a lib module's doc is missing or does not state its ports/parameters. Reuse such modules rather than redesigning.

Read the full file on GitHub · 239 lines

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. 11d ago First seen · 239 lines · 30 tokens per session scan A 58c66328ab07

Subscribe to this mod's changes

varch is a skill published in the GitHub repository phamcuong21478/rtl-skills (11 stars, last pushed 3mo ago), licensed Apache-2.0. It adds 30 tokens to every session and 3,313 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 2026-08-31.