nw-fp-haskell SKILL.md skillB

nw-fp-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-fp-haskell@git:20260829.e97726a

Pins git:20260829.e97726a in mdr.lock. Pin the fingerprint instead.

Audit grade: B, 16 of 17 checks passed
Kind: SKILL.md skill
Repository: nwave-ai/nwave
Path: nWave/skills/nw-fp-haskell/SKILL.md
Versions recorded: 5
Latest version: git:20260829.e97726a, committed Aug 29, 2026
First version recorded: Mar 17, 2026
Size: 7,481 bytes
Repository stars: 633
License: MIT

Haskell language-specific patterns, GADTs, type classes, and effect systems.

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

# FP in Haskell -- Functional Software Crafter Skill

Cross-references: [fp-principles](../nw-fp-principles/SKILL.md) | [fp-domain-modeling](../nw-fp-domain-modeling/SKILL.md) | [property-based-testing](../nw-property-based-testing/SKILL.md)

## When to Choose Haskell

- Best for: correctness-critical systems | compiler-enforced purity | maximum type safety | financial systems
- Not ideal for: teams needing fast onboarding | rapid prototyping | .NET/JVM platform requirements

## [STARTER] Quick Setup

```bash
# Install GHCup (manages GHC, cabal, stack, HLS)
curl --proto '=https' --tlsv1.2 -sSf https://get-ghcup.haskell.org | sh

# Create project
mkdir order-service && cd order-service && cabal init --interactive
# Or: stack new order-service simple && stack build && stack test
```

**Test runner**: `cabal test` or `stack test`. Add `hspec`, `QuickCheck`, `hedgehog` to `build-depends`.

## [STARTER] Type System for Domain Modeling

### Choice Types (Sum Types)

```haskell
data PaymentMethod
  = CreditCard CardNumber ExpiryDate
  | BankTransfer AccountNumber
  | Cash
  deriving (Eq, Show)
```

### Record Types and Newtypes

```haskell
data Customer = Customer
…

Read the whole file at its exact version.

How to install

The exact contents, by fingerprint

mdr add nwave-ai/nwave/nw-fp-haskell@sha256:1757e50534b73f75

The line at the top of this page pins the label git:20260829.e97726a, 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_q4gvcralmsxy73fu.svg)](https://markdownregistry.com/a/art_q4gvcralmsxy73fu)

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

Versions

The registry has recorded 5 versions of this file, between Mar 17, 2026 and Aug 29, 2026, about one every 41 days.

version	committed	commit	size	audit
git:20260829.e97726a latest	2026-08-29	e97726a	7,481 B	B	view · diff
git:20260407.2d944b1	2026-04-07	2d944b1	7,437 B	B	view · diff
git:20260320.d98f3cb	2026-03-20	d98f3cb	7,397 B	B	view · diff
git:20260318.e6a0e19	2026-03-18	e6a0e19	7,375 B	B	view · diff
git:20260317.1d16147	2026-03-17	1d16147	7,366 B	B	view

Audit of the latest version

B 16 of 17 checks passed. Fixed automatic checks with no AI involved, so the same checks give the same answer every run.

fail: No curl or wget piped into a shell (matched: curl --proto '=https' --tlsv1.2 -sSf https://get-ghcup.haskell.org | sh)
pass: Frontmatter block present
pass: Frontmatter declares a name
pass: Frontmatter declares a description
pass: Size between 200 bytes and 200 KB (7481 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 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

Starting a new one? Use a template for SKILL.md on mdpantry, which passes every one of these checks and says what to change in it.

Source

GitHub

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

API

GET https://markdownregistry.com/api/v1/artifacts/art_q4gvcralmsxy73fu
GET https://markdownregistry.com/api/v1/resolve?ref=nwave-ai/nwave/nw-fp-haskell
GET https://markdownregistry.com/api/v1/blob/1757e50534b73f7548ed14670748165bed55f7d13219f35939119ee331e4d331

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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