Automated summary
This skill brings in an expert Haskell engineer to guide strongly typed functional design, pure architecture, and performance tuning.
Strengths
- Covers advanced types: GADTs, type families, phantom types, and invariant-carrying newtypes
- Addresses concurrency with STM, async, and exception-safe combinators
- Includes project tooling: Cabal/Stack setup, dependency hygiene, profiling, and strictness
- Encourages total functions, isolated effects, and QuickCheck/Hspec property-based tests
Limitations
- Instructions are fairly generic and point to a resources/implementation-playbook.md that is not included in the SKILL.md
- No detailed procedure for migrating existing code or debugging compilation errors
- Does not cover the Haskell web/frontend ecosystem beyond brief mentions of Aeson and Megaparsec
Use it when designing or refactoring Haskell code that needs expressive types, enforced invariants, and a clean split between pure logic and effects.
Avoid it for non-Haskell tasks or purely operational work with no functional design component.
Security analysis
SafeThe skill contains only Haskell engineering guidance and references a local playbook file. It declares no tools, executes no commands, and has no destructive, exfiltration, obfuscation, or safety-disabling behavior.
No concerns found
How this analysis is madeExamples
Refactor this payment state machine in Haskell to use GADTs and phantom types so invalid transitions fail at compile time, and show me the resulting module.Review this Haskell service that shares state across lightweight threads; propose an STM-based design with exception-safe async handling and explain the trade-offs.My Haskell parser is slow and leaks memory. Help me fix strictness issues, set up profiling with Cabal, and add Hspec/QuickCheck tests for the parsing logic.name: haskell-pro description: "Expert Haskell engineer specializing in advanced type systems, pure" risk: unknown source: community date_added: "2026-02-27"
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.
- If detailed examples are required, open
resources/implementation-playbook.md.
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
- Use expressive types, newtypes, and invariants to model domain logic
- Prefer pure functions and isolate IO to explicit boundaries
- Recommend safe, total alternatives to partial functions
- Use typeclasses and algebraic design only when they add clarity
- Keep modules small, explicit, and easy to reason about
- Suggest language extensions sparingly and explain their purpose
- 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.
From the file to a first result
The download contains exactly the content displayed on this page. This copy may differ from the latest version in the source repository.
View the source and supporting filesThis download contains SKILL.md only. Any scripts, references, templates and dependencies are not included. Get the required files from the source, preserving their directory structure, before continuing.
1. Download the file
Download SKILL.mdFrom the root of a test project, save the file as .skill-downloads/haskell-pro-mrx3xz8t/SKILL.md, or use the command below. This folder is for inspecting the skill before installation.
Command for macOS/Linux or WSL: requires a POSIX shell and curl. On Windows without WSL, use the download button and create the folder manually.
mkdir -p '.skill-downloads/haskell-pro-mrx3xz8t' && curl --fail --show-error --location 'https://skills-guides.com/api/skills/haskell-pro-mrx3xz8t/download' --output '.skill-downloads/haskell-pro-mrx3xz8t/SKILL.md.part' && mv '.skill-downloads/haskell-pro-mrx3xz8t/SKILL.md.part' '.skill-downloads/haskell-pro-mrx3xz8t/SKILL.md'2. Check prerequisites
Read SKILL.md before using it. If it references scripts or external services, inspect them and prepare the required access in your test environment.
No recognized prerequisites section in this file. This does not mean it is self-contained: libraries, tools and access requirements may be mentioned elsewhere in the content or source repository.
The platforms on this page are catalog indications. The paths below follow tool documentation; they do not prove this skill has been run in those tools. No minimum tool version is confirmed for this listing.
3. Load the skill
After inspection, copy the complete folder into your project using one of the commands below, then open a new tool session. The command stops if a folder with the same name already exists: compare the files before replacing it.
Claude Code
test -f '.skill-downloads/haskell-pro-mrx3xz8t/SKILL.md' && test -s '.skill-downloads/haskell-pro-mrx3xz8t/SKILL.md' && mkdir -p '.claude/skills' && test ! -e '.claude/skills/haskell-pro' && cp -R '.skill-downloads/haskell-pro-mrx3xz8t' '.claude/skills/haskell-pro'Cursor
test -f '.skill-downloads/haskell-pro-mrx3xz8t/SKILL.md' && test -s '.skill-downloads/haskell-pro-mrx3xz8t/SKILL.md' && mkdir -p '.cursor/skills' && test ! -e '.cursor/skills/haskell-pro' && cp -R '.skill-downloads/haskell-pro-mrx3xz8t' '.cursor/skills/haskell-pro'Codex
test -f '.skill-downloads/haskell-pro-mrx3xz8t/SKILL.md' && test -s '.skill-downloads/haskell-pro-mrx3xz8t/SKILL.md' && mkdir -p '.agents/skills' && test ! -e '.agents/skills/haskell-pro' && cp -R '.skill-downloads/haskell-pro-mrx3xz8t' '.agents/skills/haskell-pro'OpenSkills
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Official OpenSkills installationopenskills install './.skill-downloads/haskell-pro-mrx3xz8t'openskills read 'haskell-pro-mrx3xz8t'Reading should display the installed file content and its base directory. It does not run the skill or install its dependencies.
For an agent that reads AGENTS.md, then sync the index. This command changes AGENTS.md: review the diff before using it.
openskills syncManual method or another tool: attach SKILL.md to a conversation, or open it in an agent that can read files. Include any required supporting resources. No universal folder is recognized by every tool.
4. Try a first task
Use a short, synthetic input: an API endpoint, a small document or an interface brief. In a new conversation, attach the file or give the agent its path, then adapt this request:
Read .skill-downloads/haskell-pro-mrx3xz8t/SKILL.md and apply its instructions to this example: [describe a test input]. Identify any missing files, dependencies or access. Produce the result requested by the skill without inventing data or running unreviewed scripts.Expected result: output matching the skill instructions, or a precise list of missing prerequisites. A read confirmation alone does not validate a first use. If an external resource is unavailable, that path remains untested.
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