A Haskell-aware code/doc browser tuned for AI agents and humans alike.
AI agents burn tokens fetching Hackage HTML and re-grepping the source tree
just to find a signature or a Haddock paragraph. hypha makes Haskell
knowledge cheap to consume: every command emits compact, structured
YAML by default (--json for machine pipelines) — no HTML noise — and
you can trim it further with --select.
It is plan-aware: hypha reads your dist-newstyle/cache/plan.json, so
answers reflect the exact versions you build against — including your local
project — and symbols point to the file:line where they are actually
defined, following a re-export through as many modules as it takes and into
another package when that is where the declaration lives. One library
powers both the CLI and a local doc-browser server, so agents and humans see
the same data.
git clone https://github.com/well-typed/hypha.git
cd hypha && cabal install exe:hypha exe:hypha-mcpcd your-cabal-project && cabal build --dry-run # writes plan.json
hypha symbol aeson/Data.Aeson/encodecabal build uses GHC 9.10.3, which the default cabal.project points at. The
other supported compilers have their own project file, each with a committed
freeze that cabal picks up automatically:
cabal build all --project-file=cabal.ghc-9.6.7.project
cabal build all --project-file=cabal.ghc-9.12.4.projectNeeds cabal >= 3.4: the project files are wired with import: rather than
symlinks, so a Windows checkout works unchanged.
Set a UTF-8 locale to build hypha. GHC derives every Handle's encoding
from the locale, so under C/POSIX — the default in bare containers, where
LANG is unset — happy cannot read ghc-lib-parser's grammar:
happy: compiler/GHC/Parser.y: hGetContents: invalid argument (cannot decode byte sequence starting from 226)
Byte 226 is the first byte of the ∷ (U+2237) in the GHC 9.12 series'
Parser.y. Fix it by giving the build a UTF-8 locale:
export LANG=C.UTF-8Running hypha needs no such thing: both binaries pin UTF-8 on their handles at startup, whatever the locale.
The full guide — installation, subcommands, the doc-browser server, MCP integration, caching, troubleshooting, and design — lives on the hypha docs site.
BSD-3-Clause. See LICENSE.