Haskell Claude Tools
An opinionated, third-party Claude Code plugin marketplace for Haskell
development. It bundles a Language Server plugin, a local documentation/source reader, on-save
formatters for sources and cabal files, and an orchestrating "super-skill" that ties them together
into one cabal-native workflow.
Marketplace name: konn-haskell-claude-tools.
What's inside
| Plugin | Provides | Invoke |
|---|
haskell-lsp-plugin | Haskell Language Server (HLS) — diagnostics, hover/types, go-to-definition, find-references, rename | LSP tools (automatic once installed) |
haskell-haddock-skill | Read local Haddock HTML docs and package source for your cabal dependencies; falls back to Hackage for the rest | /haddock <package> [module] |
haskell-format-skill | Format .hs/.lhs/.hsig sources with the project's formatter (fourmolu/ormolu/stylish-haskell); on-save hook formats automatically | /haskell-format |
haskell-cabal-gild-skill | Format .cabal/cabal.project files with cabal-gild; on-save hook formats automatically and refreshes discover module lists | /haskell-cabal-gild |
haskell-skill | Orchestrating super-skill for cabal nix-style development; drives the LSP, Haddock, Hoogle, and the formatters | /haskell (or any Haskell dev task) |
The Hoogle search skills (/hoogle:search, /hoogle:remote) come from the external
claude-hoogle marketplace, which haskell-skill
declares as a dependency.
Requirements
- Claude Code with plugin support.
- haskell-language-server —
haskell-language-server-wrapper must be on your PATH (e.g. installed via GHCup) for haskell-lsp-plugin.
- cabal ≥ 3.12 and GHC, used in nix-style (
cabal.project) mode. haskell-haddock-skill relies on cabal path and dist-newstyle/cache/plan.json.
- For the formatting plugins (used by their on-save hooks): cabal-gild for
haskell-cabal-gild-skill, and one of fourmolu / ormolu / stylish-haskell for haskell-format-skill. If a tool isn't on your PATH, its hook quietly does nothing.
- The
claude-hoogle marketplace, for the Hoogle skills (see Installation).
Installation
Add this marketplace, then install the plugin(s) you want:
/plugin marketplace add https://github.com/konn/haskell-claude-marketplace
/plugin install haskell-skill@konn-haskell-claude-tools
haskell-skill depends on the hoogle plugin from another marketplace. Because Claude Code does
not silently pull plugins across marketplaces, add claude-hoogle first so the dependency can
resolve:
/plugin marketplace add https://github.com/m4dc4p/claude-hoogle
/plugin install haskell-skill@konn-haskell-claude-tools
Install individual pieces instead if you prefer:
/plugin install haskell-lsp-plugin@konn-haskell-claude-tools
/plugin install haskell-haddock-skill@konn-haskell-claude-tools
/plugin install haskell-format-skill@konn-haskell-claude-tools
/plugin install haskell-cabal-gild-skill@konn-haskell-claude-tools
Using the tools
/haskell — development workflow
The entry point for Haskell work. It treats cabal.project as the source of truth, works
package-by-package, formats before compiling (via /haskell-format and /haskell-cabal-gild),
prefers the LSP over a full cabal build for quick feedback, and prefers local documentation over
remote lookups. It delegates to /haddock and the Hoogle skills for API discovery.
/haddock — local docs & source
Reads documentation and source for your project's dependencies from cabal's local store and
repo-cache, so you avoid hitting Hackage. One-time setup per project:
cabal configure --enable-documentation # ensures `documentation: True`
cabal build all # materialises docs/source for dependencies
It then resolves each dependency through cabal path and the UnitId recorded in
dist-newstyle/cache/plan.json (cabal abbreviates package names in the store, so paths cannot be
guessed from the package name). Packages outside the dependency set fall back to
Hackage.
/haskell-format — format sources
Formats .hs/.lhs/.hsig with the project's formatter, chosen by config (fourmolu.yaml /
.fourmolu.yaml → fourmolu, .stylish-haskell.yaml → stylish-haskell) or the first of
fourmolu → ormolu → stylish-haskell found on PATH. An on-save hook runs it automatically whenever
such a file is written, so code stays formatted without an explicit call.
