nw-pbt-haskell SKILL.md skillA

nw-pbt-haskell from nwave-ai/nwave is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.

Install it, pinned

mdr add nwave-ai/nwave/nw-pbt-haskell@git:20260320.d98f3cb

Pins git:20260320.d98f3cb in mdr.lock. Pin the fingerprint instead.

Audit grade: A, 17 of 17 checks passed
Kind: SKILL.md skill
Repository: nwave-ai/nwave
Path: nWave/skills/nw-pbt-haskell/SKILL.md
Versions recorded: 3
Latest version: git:20260320.d98f3cb, committed Mar 20, 2026
First version recorded: Mar 17, 2026
Size: 6,228 bytes
Repository stars: 633
License: MIT

Haskell property-based testing with QuickCheck and Hedgehog frameworks.

Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.

What the file says

# PBT Haskell -- QuickCheck + Hedgehog

## Framework Selection

| Framework | Shrinking | Stateful | Choose When |
|-----------|-----------|----------|-------------|
| QuickCheck | Type-based (manual) | Limited (open-source) | Default for most projects. Universal ecosystem support. |
| Hedgehog | Integrated (automatic) | Yes (parallel too) | Need automatic shrinking composition or parallel stateful testing |

QuickCheck is the original PBT framework (2000). Hedgehog is the modern alternative with better shrinking.

## Quick Start (QuickCheck)

```haskell
import Test.QuickCheck

prop_reverse_involutory :: [Int] -> Bool
prop_reverse_involutory xs = reverse (reverse xs) == xs

-- Run: quickCheck prop_reverse_involutory
-- Or in test suite: testProperty "reverse" prop_reverse_involutory
```

## Generator Cheat Sheet (QuickCheck)

### Via Arbitrary Type Class
```haskell
arbitrary :: Gen Int       -- any Int
arbitrary :: Gen String    -- any String
arbitrary :: Gen [Int]     -- any list of Ints
arbitrary :: Gen Bool

-- Custom Arbitrary
data Color = Red | Green | Blue deriving (Show, Eq)

instance Arbitrary Color where
  arbitrary = elements [Red, Green, Blue]
  shrink Red = []
…

Read the whole file at its exact version.

How to install

The exact contents, by fingerprint

mdr add nwave-ai/nwave/nw-pbt-haskell@sha256:b62a6f5b949fc2f4

The line at the top of this page pins the label git:20260320.d98f3cb, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.

Badge

[![mdr](https://markdownregistry.com/badge/art_ppjneiw2qidudir7.svg)](https://markdownregistry.com/a/art_ppjneiw2qidudir7)

0 badge image fetches in 30 days. What the badge shows.

Versions

The registry has recorded 3 versions of this file, between Mar 17, 2026 and Mar 20, 2026, about one every day.

version	committed	commit	size	audit
git:20260320.d98f3cb latest	2026-03-20	d98f3cb	6,228 B	A	view · diff
git:20260318.e6a0e19	2026-03-18	e6a0e19	6,206 B	A	view · diff
git:20260317.1d16147	2026-03-17	1d16147	6,197 B	A	view

Audit of the latest version

A 17 of 17 checks passed. Fixed automatic checks with no AI involved, so the same checks give the same answer every run.

pass: Frontmatter block present
pass: Frontmatter declares a name
pass: Frontmatter declares a description
pass: Size between 200 bytes and 200 KB (6228 bytes)
pass: No zero-width or bidi control characters
pass: No instruction hidden inside an HTML comment
pass: No link to an exfiltration or paste host
pass: No credential-shaped string
pass: No instruction to send local credentials anywhere
pass: No text hidden with inline styles
pass: No prompt-injection phrasing
pass: No curl or wget piped into a shell
pass: No recursive delete of root, home or parent
pass: No instruction to read or print local credentials
pass: No base64 blob over 200 characters
pass: No link to a raw IP address
pass: No script tag

Source

GitHub

nwave-ai/nwave · 633 stars · license MIT · pushed 2026-11-07 · branch main

API

GET https://markdownregistry.com/api/v1/artifacts/art_ppjneiw2qidudir7
GET https://markdownregistry.com/api/v1/resolve?ref=nwave-ai/nwave/nw-pbt-haskell
GET https://markdownregistry.com/api/v1/blob/b62a6f5b949fc2f4db733dae6d222cfea12f33293e8ef05b31b397826b03e030

Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.

Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.

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