nw-fp-scala

nw-fp-scala is a skill for Claude Code from nWave-ai/nWave. It costs 22 tokens per session (1,656 once invoked), scanned A, original, MIT.

A guide to functional programming in Scala 3, a language for the Java platform. It covers type-safe domain models and libraries including ZIO, Cats Effect, and ScalaCheck.

In plain words
What is it for?
Use it to set up Scala projects, model domains with case classes and opaque types, and work with functional libraries and tests.
Why use it?
It helps Scala developers represent business concepts clearly and structure programs that handle effects such as I/O and errors.

Skill for Claude Code

Written for Claude Code: disable-model-invocation in frontmatter. Also seen: agent in frontmatter.

Good fit Use it to set up Scala projects, model domains with case classes and opaque types, and work with functional libraries and tests.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/nwave-ai/nwave/nw-fp-scala
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 nWave-ai/nWave --skill nw-fp-scala
Clone the repo
git clone --depth 1 https://github.com/nWave-ai/nWave

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 nw-fp-scala

README.md
[![agentmods](https://agentmods.dev/badge/skills/nwave-ai/nwave/nw-fp-scala/github.svg)](https://agentmods.dev/skills/nwave-ai/nwave/nw-fp-scala)
Your own site
<a href="https://agentmods.dev/skills/nwave-ai/nwave/nw-fp-scala"><img src="https://agentmods.dev/badge/skills/nwave-ai/nwave/nw-fp-scala/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 nw-fp-scala

Your own site · 80×15
<a href="https://agentmods.dev/skills/nwave-ai/nwave/nw-fp-scala"><img src="https://agentmods.dev/badge/skills/nwave-ai/nwave/nw-fp-scala.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 22 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,656 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 $0.00022 $0.01656
Opus 5 $0.00011 $0.00828
Sonnet 5 $0.00004 $0.00331
Haiku 4.5 $0.00002 $0.00166

Measured 7d ago against content hash b594aa82bd6e, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

nw-fp-scala 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 7d 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.

nWave/skills/nw-fp-scala/SKILL.md · 195 lines

How it starts

The opening of the file, as written. The whole thing — 195 lines — stays where its author put it; the contents beside it link to each section on GitHub.

FP in Scala 3 -- Functional Software Crafter Skill

Cross-references: fp-principles | fp-domain-modeling | property-based-testing

When to Choose Scala

  • Best for: JVM with full FP power | large-scale systems | data engineering | richest effect ecosystem
  • Not ideal for: small teams wanting simplicity | Android (use Kotlin) | teams allergic to OO/FP duality

[STARTER] Quick Setup

cs install scala3-compiler scala3-repl sbt
sbt new scala/scala3.g8 && cd order-service
# Add zio, zio-test, scalacheck to build.sbt
sbt compile && sbt test

[STARTER] Type System for Domain Modeling

Choice Types and Record Types

enum PaymentMethod:
  case CreditCard(cardNumber: String, expiryDate: String)
  case BankTransfer(accountNumber: String)
  case Cash

case class Customer(
  customerId: CustomerId,
  customerName: CustomerName,
  customerEmail: EmailAddress
)

Case classes provide structural equality, copy, and pattern matching for free.

[STARTER] Domain Wrappers (Opaque Types) -- Zero Cost

object OrderDomain:
  opaque type OrderId = Int
  object OrderId:
    def apply(value: Int): OrderId = value
  extension (id: OrderId) def value: Int = id

  opaque type EmailAddress = String
  object EmailAddress:
    def from(raw: String): Either[ValidationError, EmailAddress] =
      if raw.contains("@") then Right(raw)
      else Left(InvalidEmail(raw))

Inside defining scope, alias is transparent. Outside, only exported operations available.

[INTERMEDIATE] Composition Style

For-Comprehensions (Monadic Chaining)

def placeOrder(raw: RawOrder): Either[OrderError, Confirmation] =
  for
    validated <- validateOrder(raw)
    priced    <- priceOrder(validated)
    confirmed <- confirmOrder(priced)
  yield confirmed

Error Accumulation (Cats Validated or ZIO)

import cats.data.Validated
import cats.syntax.all.*

def validateCustomer(raw: RawCustomer): ValidatedNel[ValidationError, Customer] =
  (validateName(raw.name), validateEmail(raw.email), validateAddress(raw.address))
    .mapN(Customer.apply)

Read the full file on GitHub · 195 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. 7d ago First seen · 195 lines · 22 tokens per session scan A b594aa82bd6e

Subscribe to this mod's changes

nw-fp-scala is a skill published in the GitHub repository nWave-ai/nWave (610 stars, last pushed 4d ago), licensed MIT. It adds 22 tokens to every session and 1,656 once invoked, about $0.0001 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 2026-09-03.

Related

Other skills, from other repositories

test-driven-development

Drives .NET/C# development with tests — RED/GREEN/REFACTOR with xUnit (v2 or v3) or MSTest, the Prove-It Pattern for bug fixes, the test pyramid with WebApplicationFactory for integration and Playwright/Avalonia.Headless for E2E. Supports both VSTest and Microsoft.Testing.Platform (MTP) runners. Use when implementing…

peterblazejewicz/claude-plugins · 103 tokens

implement

Use in the Implement phase whenever writing or editing production Java code, or fixing a bug, in a Spring/Spring Boot project. Enforces test-first (red-green-refactor), executes the approved plan step by step, and honors the project's path-scoped tech-stack rules and the task's enforcement set. Preloaded into…

taipt1504/claudehut · 73 tokens

kotlin-testing

Kotlin testing patterns with Kotest, MockK, coroutine testing, property-based testing, and Kover coverage. Follows TDD methodology with idiomatic Kotlin practices.

affaan-m/ECC · 38 tokens

rust-testing

Rust testing patterns including unit tests, integration tests, async testing, property-based testing, mocking, and coverage. Follows TDD methodology.

affaan-m/ECC · 31 tokens

cpp-testing

Use only when writing/updating/fixing C++ tests, configuring GoogleTest/CTest, diagnosing failing or flaky tests, or adding coverage/sanitizers.

affaan-m/ECC · 34 tokens

temporal-python-testing

Test Temporal workflows with pytest, time-skipping, and mocking strategies. Covers unit testing, integration testing, replay testing, and local development setup. Use when implementing Temporal workflow tests or debugging test failures.

wshobson/agents · 45 tokens