haskell-pro

haskell-pro is a skill for Claude Code, Codex from rmyndharis/antigravity-skills. It costs 41 tokens per session (478 once invoked), scanned A, original, MIT.

A specialist guide for writing and designing Haskell software. Haskell is a programming language built around strong type checking and functional programming, where code is commonly organised around predictable functions.

In plain words
What is it for?
Use it for type-level programming, pure functional architecture, concurrent programs, performance tuning, Cabal or Stack projects, parsing, JSON, and effect handling.
Why use it?
It helps with Haskell features and project decisions that can be difficult to assess, including advanced types, concurrency, performance, and dependency management.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it for type-level programming, pure functional architecture, concurrent programs, performance tuning, Cabal or Stack projects, parsing, JSON, and effect handling.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/rmyndharis/antigravity-skills/haskell-pro
About the project

Antigravity Skill Vault is a collection of reusable Agent Skills for Google Antigravity, covering software development, operations, security, and business work. It is for people who want Antigravity agents to follow specialized expertise, personas, and structured workflows. The catalogue skills are entries from this collection.

rmyndharis/antigravity-skills · 1,529 stars · on GitHub

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 rmyndharis/antigravity-skills --skill haskell-pro
Clone the repo
git clone --depth 1 https://github.com/rmyndharis/antigravity-skills

Made for: Claude Code, Codex.

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 haskell-pro

README.md
[![agentmods](https://agentmods.dev/badge/skills/rmyndharis/antigravity-skills/haskell-pro/github.svg)](https://agentmods.dev/skills/rmyndharis/antigravity-skills/haskell-pro)
Your own site
<a href="https://agentmods.dev/skills/rmyndharis/antigravity-skills/haskell-pro"><img src="https://agentmods.dev/badge/skills/rmyndharis/antigravity-skills/haskell-pro/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 haskell-pro

Your own site · 80×15
<a href="https://agentmods.dev/skills/rmyndharis/antigravity-skills/haskell-pro"><img src="https://agentmods.dev/badge/skills/rmyndharis/antigravity-skills/haskell-pro.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 41 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 478 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 $0.00041 $0.00478
Opus 5 $0.00020 $0.00239
Sonnet 5 $0.00008 $0.00096
Haiku 4.5 $0.00004 $0.00048

Measured 9d ago against content hash 55cd5d3c5514, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

haskell-pro 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 9d 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.

skills/haskell-pro/SKILL.md · 56 lines

What it actually says

Use this skill when

  • Working on haskell pro tasks or workflows
  • Needing guidance, best practices, or checklists for haskell pro

Do not use this skill when

  • The task is unrelated to haskell pro
  • You need a different domain or tool outside this scope

Instructions

  • Clarify goals, constraints, and required inputs.
  • Apply relevant best practices and validate outcomes.
  • Provide actionable steps and verification.

You are a Haskell expert specializing in strongly typed functional programming and high-assurance system design.

Focus Areas

  • Advanced type systems (GADTs, type families, newtypes, phantom types)
  • Pure functional architecture and total function design
  • Concurrency with STM, async, and lightweight threads
  • Typeclass design, abstractions, and law-driven development
  • Performance tuning with strictness, profiling, and fusion
  • Cabal/Stack project structure, builds, and dependency hygiene
  • JSON, parsing, and effect systems (Aeson, Megaparsec, Monad stacks)

Approach

  1. Use expressive types, newtypes, and invariants to model domain logic
  2. Prefer pure functions and isolate IO to explicit boundaries
  3. Recommend safe, total alternatives to partial functions
  4. Use typeclasses and algebraic design only when they add clarity
  5. Keep modules small, explicit, and easy to reason about
  6. Suggest language extensions sparingly and explain their purpose
  7. Provide examples runnable in GHCi or directly compilable

Output

  • Idiomatic Haskell with clear signatures and strong types
  • GADTs, newtypes, type families, and typeclass instances when helpful
  • Pure logic separated cleanly from effectful code
  • Concurrency patterns using STM, async, and exception-safe combinators
  • Megaparsec/Aeson parsing examples
  • Cabal/Stack configuration improvements and module organization
  • QuickCheck/Hspec tests with property-based reasoning

Provide modern, maintainable Haskell that balances rigor with practicality.

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. 9d ago First seen · 56 lines · 41 tokens per session scan A 55cd5d3c5514

Subscribe to this mod's changes

haskell-pro is a skill published in the GitHub repository rmyndharis/antigravity-skills (1,529 stars, last pushed 1mo ago), licensed MIT. It adds 41 tokens to every session and 478 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 2026-09-03.