RTLDesignSherpa: Skill for Claude Code

.claude/skills/fsm-discipline/SKILL.md

fsm-discipline is a skill for Claude Code from sean-galloway/RTLDesignSherpa. It costs 38 tokens per session (441 once invoked), scanned A, original, MIT.

A hardware-design guide for minimizing state machines, which are control structures that move through named operating states. It recommends pipelines for beat-by-beat data paths and small state machines for control tasks.

In plain words
What is it for?
Use it when designing or reviewing streaming hardware blocks, data pipelines, schedulers, initialization logic, or error recovery.
Why use it?
It helps avoid throughput and backpressure problems caused by putting state machines in the data path.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

This is sean-galloway/RTLDesignSherpa's own configuration. It tells Claude Code how to work on RTLDesignSherpa itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything RTLDesignSherpa configures →

Reuse

Borrowing it

Nothing to install: this file belongs to sean-galloway/RTLDesignSherpa. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/sean-galloway/RTLDesignSherpa/main/.claude/skills/fsm-discipline/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/sean-galloway/RTLDesignSherpa

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 fsm-discipline

README.md
[![agentmods](https://agentmods.dev/badge/skills/sean-galloway/rtldesignsherpa/fsm-discipline/github.svg)](https://agentmods.dev/skills/sean-galloway/rtldesignsherpa/fsm-discipline)
Your own site
<a href="https://agentmods.dev/skills/sean-galloway/rtldesignsherpa/fsm-discipline"><img src="https://agentmods.dev/badge/skills/sean-galloway/rtldesignsherpa/fsm-discipline/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 fsm-discipline

Your own site · 80×15
<a href="https://agentmods.dev/skills/sean-galloway/rtldesignsherpa/fsm-discipline"><img src="https://agentmods.dev/badge/skills/sean-galloway/rtldesignsherpa/fsm-discipline.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 441 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 pass 7 Sept 2026
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 $0.00441
Opus 5 $0.00019 $0.00220
Sonnet 5 $0.00008 $0.00088
Haiku 4.5 $0.00004 $0.00044

Measured 11d ago against content hash ee87c07cea61, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

fsm-discipline 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.

.claude/skills/fsm-discipline/SKILL.md · 35 lines

What it actually says

fsm-discipline

READ FIRST: vault/handbook/INDEX.md (the handbook is the repo's memory; this skill is the signpost). Canonical: vault/handbook/design/streaming-no-fsm.md (the datapath rule) and vault/handbook/design/minimal-fsm.md (the control-path rule).

Two rules, and the first is absolute:

1. No FSM in the per-beat data path. Not a minimal one, not a two-state one. Datapath blocks are valid/ready pipelines: s_ready = !r_valid || m_ready, register the beat, propagate backpressure. An FSM there caps throughput at one beat per state visit, and forces a separate correctness argument per state for m_ready deasserting mid-beat — which is where the bugs that reach silicon live.

2. Where an FSM IS right — control paths: descriptor lifecycle, schedulers, init sequencers, error recovery — keep it minimal. Fewest states carrying real distinctions; two-process form with a default-hold; one FSM per module.

The dividing question is not "is this complicated?" but "does this logic see per-beat data?" If yes, it is datapath, and it gets a pipeline.

Before minimizing a machine, ask whether it should exist. The handbook note has the substitution table (counter for a waiting state, r_valid for a mid-burst state, arbiter for a turn-taking state) and the pumice precedent, where retiring whole FSMs into counters plus qualifiers came out both simpler and faster.

The handbook root is vault/handbook/INDEX.md - design/, dv/, fpga/, authoring/ areas, atomic notes, wikilinked. When you learn a durable lesson in this domain, ADD IT TO THE HANDBOOK NOTE, not to this skill.

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 · 35 lines · 38 tokens per session scan A ee87c07cea61

Subscribe to this mod's changes

fsm-discipline is a skill published in the GitHub repository sean-galloway/RTLDesignSherpa (23 stars, last pushed today), licensed MIT. It adds 38 tokens to every session and 441 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 2026-08-30.