| name | haskell |
| description | Super-skill for developing Haskell projects with cabal nix-style builds. Orchestrates the Haskell Language Server, Haddock, and Hoogle tools into one workflow instead of duplicating them. Use when: (1) writing/editing/refactoring Haskell (.hs/.lhs/.hsig/.cabal/package.yaml) code, (2) building or typechecking a cabal project, (3) fixing compiler or type errors, (4) renaming or looking up symbols, (5) adding or changing dependencies. Treats cabal.project as the source of truth, prefers the LSP before full builds, and local docs over remote. Trigger: "/haskell" or any Haskell development task.
|
Haskell Development Super-Skill
The entry point for Haskell development in this environment. It coordinates the other
tools in the konn-haskell-claude-tools marketplace (plus the external Hoogle marketplace)
rather than reimplementing them.
Ground rules
- cabal nix-style builds only.
cabal.project (+ cabal.project.local) is the source of
truth. Do not use stack or invoke ghc directly.
- Package by package. In a multi-package project, work on and build one package at a time
(
cabal build <pkg>), getting it green before moving on — not cabal build all.
- Format before compiling. Format changed source files with
/haskell-format (fourmolu /
ormolu / stylish-haskell) and changed .cabal / cabal.project files with
/haskell-cabal-gild before building. Both also run automatically via their on-save hooks.
(<>) over (++) for all concatenation, including lists and strings.- After editing any
package.yaml, run hpack to regenerate the .cabal file.
Workflow
- Edit the code (format first).
- Typecheck with the LSP before any full build. With
haskell-lsp-plugin installed, use
the Haskell Language Server via the LSP tools for diagnostics, hover/types,
go-to-definition, find-references, and rename. This is far faster than cabal build and is
the default for quick feedback and refactors — reach for it before a full-scale build.
- Look up APIs when you need a signature, instance, or implementation. Prefer local
information over remote to avoid loading Haskell's public infrastructure:
/haddock <pkg> [module] — local Haddock docs and source for project dependencies (preferred)./hoogle:search — search by name or type signature./hoogle:remote — remote Hoogle, only when local search is insufficient.
- Build with cabal once the LSP is clean:
cabal build <pkg>. Fix errors, then move to the
next package.
- Test:
cabal test <pkg> (or cabal run <pkg>:<test-suite>).
Adding / changing dependencies
- Edit
package.yaml / *.cabal (or cabal.project for source-repository-packages), run
hpack if the project uses hpack, reformat the cabal/project files with /haskell-cabal-gild
(or let its on-save hook do it), then run cabal build all once so the build plan and local
docs refresh.
- After dependencies change,
/haddock will not resolve new packages locally until
cabal build all has run (and documentation: True is set).
Companion tools
| Need | Use |
|---|
| Typecheck, types, definitions, references, rename | haskell-lsp-plugin (LSP tools) |
Format .hs/.lhs/.hsig sources | /haskell-format |
Format .cabal / cabal.project files | /haskell-cabal-gild |
| Docs / source of a dependency | /haddock |
| Find a function by name or type | /hoogle:search, then /hoogle:remote |
