# guardrails

Sets up project rules as checks in places like Git hooks and CI. Useful when documenting a rule has not stopped it from being broken.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · ★ 24
- Author: rainmanjam
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/rainmanjam/poka-yoke/tree/HEAD/plugins/poka-yoke/skills/guardrails/SKILL.md
- Updated: 2026-10-14
- HTML: https://affpapa.org/en/nevibecode/skills/guardrails

## What it does

The skill helps choose where a project rule should be enforced: in the type system, a linter, a Git hook, CI, a database constraint, or a runtime check. It aims to produce working configuration for the project’s stack, rather than a review of code that is still being built.

Templates cover pre-commit, GitHub Actions, ESLint, Ruff, and Claude Code hooks. For existing violations, the skill recommends establishing a baseline and tightening the rule over time. It also checks whether the repository already has a configuration that could enforce the rule. A pre-commit hook can be skipped with `--no-verify`, so important checks need a required CI check backed by branch protection.

The guidance includes testing a new guardrail by deliberately introducing the mistake it should catch. For rules that constrain the AI agent itself, use `agent-guardrails` instead.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add rainmanjam/poka-yoke --skill guardrails -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/guardrails/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/guardrails/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add rainmanjam/poka-yoke --skill guardrails -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/guardrails/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add rainmanjam/poka-yoke --skill guardrails -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/guardrails/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install rainmanjam/poka-yoke guardrails
```

2. **Manually: put the files in place**
- File: `.github/skills/guardrails/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add rainmanjam/poka-yoke --skill guardrails -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/rainmanjam/poka-yoke --path plugins/poka-yoke/skills/guardrails
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/guardrails/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add rainmanjam/poka-yoke --skill guardrails -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/rainmanjam/poka-yoke/tree/HEAD/plugins/poka-yoke/skills/guardrails/SKILL.md

## When to use it
- block secrets from entering commits
- require type checks before code can merge
- prevent unsafe database migrations
- fail CI when tests are left skipped
- tighten checks without blocking existing violations

## Example prompts
- Set up a required CI type check and prevent merges when it fails.
- Add a pre-commit secret check while accounting for existing violations.
- Check whether this repository already blocks unsafe database migrations and enforce that rule.

## Source text · SKILL.md · MIT

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: a2f30d2b7d79e979.

BEGIN THIRD-PARTY FILE a2f30d2b7d79e979
```text
---
name: guardrails
description: >-
  Pre-commit hooks, CI gates, lint rules, database constraints and branch protection. Use when a rule needs enforcing rather than documenting: "set up enforcement", "unformatted or untyped code must not get merged", "gate this in CI", "we agreed to X and people still do not", "stop secrets getting committed". Covers baselining and ratcheting so existing violations do not block anyone. For constraining an AI agent use agent-guardrails.
---

# Poka-Yoke Guardrails

Design-time devices protect the code you are writing now. Guardrails protect the code
everyone writes later, including the version of you who is in a hurry. They are Shingo's
*successive check*: the next station refuses to accept bad work.

The reason this mode exists as its own thing: the most common failure in software quality is
agreeing on a rule and then writing it down. A rule in a wiki has a half-life of about one
onboarding. The same rule wired into a gate applies itself and costs nothing to remember.

## Building, not reviewing

Most of the time this mode is reached *while someone is building the thing*, not afterwards.
That changes the deliverable. They asked for the config, so produce the config, working, complete,
in their stack. Do not hand back a severity table when the person is mid-feature; a list of
findings about code they have not written yet is not useful to them.

Then add a short closing note, three or four lines, covering:

- which misuses the shape you chose makes impossible, and at which rung,
- what you left possible on purpose, and why that tradeoff is the right one here.

That closing note is what stops the device being undone in six months by someone who cannot
see why it is there. It is also the difference between mistake-proofing and a code generator:
the reasoning travels with the code.

When the code already exists and they are asking what is wrong with it, switch to the audit
voice, ranked findings with the mistake, the consequence, and the device. Match the mode to
where they are in the work, not to this file's default.

## Pick the earliest gate that can hold the rule

The same rule can live at several points in the lifecycle. Earlier is better, feedback is
faster, cheaper, and lands while the author still has the context in their head. But earlier
is also easier to bypass. The resolution is to place the device early **and** back it with a
gate that cannot be skipped.

| Gate | Feedback speed | Bypassable? | Best for |
|---|---|---|---|
| Type system / compiler | instant | no | anything the types can express, always first choice |
| Editor + lint | seconds | yes (ignore comment) | style, banned APIs, unsafe patterns |
| Pre-commit hook | seconds | yes (`--no-verify`) | fast checks: secrets, formatting, obvious footguns |
| Pre-push hook | ~a minute | yes | medium checks you don't want to wait for on every commit |
```
END THIRD-PARTY FILE a2f30d2b7d79e979

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