hk

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Set up and maintain hk git hook manager in any repository. Use when adding pre-commit hooks, configuring linters, setting up code quality automation, working with hk.pkl, or maintaining existing hook configurations. Triggers on tasks involving hk, git hooks, pre-commit checks, commit-msg validation, or linting pipelines.

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npx skill4agent add connorads/dotfiles hk

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Translated version includes tags in frontmatter

hk — Git Hook Manager

hk by jdx runs linters and formatters as git hooks with built-in parallelism, file locking (no race conditions), and staged-file-only operation (no separate lint-staged needed). Config is in Pkl — Apple's typed configuration language.

Mental Model

Every hk setup is three steps: detect what the project has → compose steps from tiers → wire the hooks in.
detect project type + tools
compose hk.pkl (tiered steps)
wire: mise.toml + .hk-hooks/ + prepare script

Setup Workflow

1. Detect

bash
hk --version                    # get current version for amends URL
ls package.json go.mod Cargo.toml pyproject.toml flake.nix Makefile
cat mise.toml package.json      # existing tools, package manager, scripts
Identify:
  • Language(s) and framework
  • Package manager (pnpm/bun/npm/yarn for JS, cargo, go, pip, etc.)
  • Formatter already configured (prettier, biome, ruff, gofmt…)
  • Linter already configured (eslint, golangci-lint, ruff, clippy…)
  • Test runner (vitest, jest, go test, cargo test, pytest…)
  • Whether it's a team/shared repo (needs no-commit-to-branch)

2. Choose steps (tiered)

Tier 1 — Universal (always add):
StepBuiltin
trailing-whitespace
Builtins.trailing_whitespace
newlines
Builtins.newlines
check-merge-conflict
Builtins.check_merge_conflict
Tier 2 — Common tools (add if relevant):
StepBuiltinWhen
typos
Builtins.typos
Always (fast spell check)
gitleakscustomAlways (secret detection)
rumdl
Builtins.rumdl
If
*.md
files exist
Tier 3 — Language-specific (see
references/builtins-by-language.md
):
Signal fileSteps to add
package.json
+
biome.json
/
biome.jsonc
biome (or ultracite), eslint
package.json
(no biome)
prettier, eslint
tsconfig.json
typecheck (tsc/tsgo/astro check/svelte-check)
go.mod
go_fmt, go_vet, golangci_lint, gomod_tidy
Cargo.toml
cargo_fmt, cargo_clippy
pyproject.toml
/
requirements.txt
ruff (format+lint), mypy
flake.nix
/
*.nix
nix_fmt (nixfmt), deadnix
*.sh
/
*.zsh
shfmt, shellcheck
Tier 4 — Project-specific (detect from config files):
SignalStep
commitlint.config.*
exists
commit-msg hook with commitlint
.yamllint*
exists
yamllint
Team/shared repono-commit-to-branch (pre-commit), no-push-to-branch (pre-push)
Test runner detectedtest step(s) — vitest/jest/go test/cargo test/pytest

3. Wire the hooks

Four files to create/update:
  1. mise.toml
    — add hk, pkl, tool binaries
  2. hk.pkl
    — configuration
  3. scripts/quiet-on-success.sh
    — noise suppressor (copy from
    assets/quiet-on-success.sh
    in this skill)
  4. .hk-hooks/pre-commit
    — tracked hook wrapper
Then:
bash
chmod +x scripts/quiet-on-success.sh .hk-hooks/*
git config --local core.hooksPath .hk-hooks
And add to
package.json
prepare script (JS projects):
json
"prepare": "[ -n \"$CI\" ] && exit 0 || command -v hk >/dev/null && (hk install 2>/dev/null || git config --local core.hooksPath .hk-hooks) || echo 'Note: hk not found, skipping git hooks. Install mise to enable.'"
For non-JS projects, set
core.hooksPath
manually or via a Makefile
setup
target.

4. Validate

bash
hk check --all      # verify all steps pass on existing files
hk validate         # verify hk.pkl is valid Pkl

Preferred Patterns

hk.pkl global settings

Always use these at the top (after the amends/import lines):
pkl
exclude = List("node_modules", "dist", ".next", ".git")  // add project-specific dirs
display_skip_reasons = List()   // suppress skip noise
terminal_progress = false        // cleaner output
Always use these on the pre-commit hook:
pkl
["pre-commit"] {
    fix = true        // auto-fix and re-stage
    stash = "git"     // isolate staged changes
    steps { ... }
}

Binary file excludes

Always exclude binary/font files from trailing-whitespace, newlines, and typos:
pkl
local binary_excludes = List(
    "*.png", "*.jpg", "*.jpeg", "*.gif", "*.webp", "*.ico",
    "*.woff", "*.woff2", "*.ttf", "*.eot", "*.pdf", "*.zip"
)

["trailing-whitespace"] = (Builtins.trailing_whitespace) {
    exclude = binary_excludes
}

The quiet-on-success wrapper

Wrap noisy commands so output only appears on failure:
pkl
["typecheck"] {
    check = "scripts/quiet-on-success.sh pnpm exec tsc --noEmit"
}
Copy
assets/quiet-on-success.sh
from this skill directory into
scripts/
in the target repo.

The .hk-hooks/pre-commit wrapper

This is the file git actually executes. It's tracked in git (unlike
.git/hooks/
):
sh
#!/bin/sh
# hk pre-commit hook — silent on success, minimal on failure
if [ -n "$CI" ]; then
  exec hk run pre-commit "$@"
fi
output=$(hk run pre-commit "$@" 2>&1)
code=$?
[ $code -ne 0 ] && printf '%s\n' "$output"
exit $code
For other hooks (commit-msg, pre-push), use simpler wrappers:
sh
#!/bin/sh
exec hk run commit-msg "$@"
sh
#!/bin/sh
exec hk run pre-push "$@"

Pkl Syntax Reference

Required first lines

pkl
amends "package://github.com/jdx/hk/releases/download/v1.36.0/hk@1.36.0#/Config.pkl"
import "package://github.com/jdx/hk/releases/download/v1.36.0/hk@1.36.0#/Builtins.pkl"
Always match the version in
amends
and
import
to the installed hk version
(
hk --version
).

Builtin step (use as-is)

pkl
["trailing-whitespace"] = Builtins.trailing_whitespace

Builtin step (with overrides)

pkl
["trailing-whitespace"] = (Builtins.trailing_whitespace) {
    exclude = List("*.png", "*.jpg")
    batch = true
}

Custom step

pkl
["typecheck"] {
    glob = List("*.ts", "*.tsx")       // optional: only run when these files staged
    check = "scripts/quiet-on-success.sh pnpm exec tsc --noEmit"
    // fix = "command to auto-fix"     // optional
}

Template variables

VariableValue
{{files}}
Space-separated list of staged files matching the step's glob
{{commit_msg_file}}
Path to commit message file (commit-msg hook only)
{{workspace}}
Directory containing
workspace_indicator
file
{{workspace_files}}
Files relative to workspace directory

Multi-line inline script

pkl
["no-commit-to-branch"] {
    check = """
      branch=$(git rev-parse --abbrev-ref HEAD)
      if [ "$branch" = "main" ] || [ "$branch" = "master" ]; then
        echo "Direct commits to '$branch' are not allowed."
        exit 1
      fi
      """
}

Local variable (share steps across hooks)

pkl
local fast_steps = new Mapping<String, Step> {
    ["trailing-whitespace"] = Builtins.trailing_whitespace
    ["shfmt"] = (Builtins.shfmt) { batch = true }
}

hooks {
    ["pre-commit"] { fix = true; stash = "git"; steps = fast_steps }
    ["check"] { steps = fast_steps }
    ["fix"] { fix = true; stash = "git"; steps = fast_steps }
}

Sequential ordering with Groups

Steps within a group run in parallel; groups run sequentially:
pkl
steps {
    ["format"] = new Group {
        steps = new Mapping<String, Step> {
            ["prettier"] { ... }
            ["eslint"] { ... }
        }
    }
    ["validate"] = new Group {   // runs after format completes
        steps = new Mapping<String, Step> {
            ["typecheck"] { ... }
            ["test"] { ... }
        }
    }
}
Or use
depends
for fine-grained ordering:
pkl
["eslint"] {
    depends = List("prettier")   // waits for prettier to finish
    ...
}

mise.toml Additions

toml
[tools]
hk = "latest"
pkl = "latest"        # required for hk.pkl parsing

# Add as needed based on detected steps:
typos = "latest"      # Tier 2: spell check
gitleaks = "latest"   # Tier 2: secret detection
rumdl = "latest"      # Tier 2: markdown lint (if .md files present)
yamllint = "latest"   # Tier 4: YAML lint (if .yamllint* present)

Maintenance

Add a new step

Insert into
hk.pkl
under the appropriate section. Check
hk builtins
for available built-ins, or write a custom step.

Update hk version

bash
hk --version   # check current
Bump both URLs in
hk.pkl
:
pkl
amends "package://github.com/jdx/hk/releases/download/v1.37.0/hk@1.37.0#/Config.pkl"
import "package://github.com/jdx/hk/releases/download/v1.37.0/hk@1.37.0#/Builtins.pkl"

Bypass hooks temporarily

bash
HK=0 git commit -m "wip"             # skip all hk hooks
HK_SKIP_STEPS=vitest git commit      # skip specific step

Debug a failing step

bash
hk check -v                          # verbose output
hk check -v --step typecheck         # single step only
hk run pre-commit -v                 # simulate hook run

Local developer overrides

Create
hk.local.pkl
(gitignored) to override settings locally:
pkl
amends "./hk.pkl"
hooks {
    ["pre-commit"] {
        steps {
            ["vitest"] {
                check = "scripts/quiet-on-success.sh pnpm exec vitest run --testPathPattern=fast"
            }
        }
    }
}

Gotchas

IssueFix
pkl: command not found
Add
pkl = "latest"
to
mise.toml
, run
mise install
amends
version mismatch
Match amends/import URL version to
hk --version
output
Builtins snake_case vs step names kebab-case
Builtins.trailing_whitespace
["trailing-whitespace"]
Hook runs but matches nothingCheck glob patterns; use
hk check -v
to see file matching
Binary files fail spell checkAdd binary excludes to typos/trailing-whitespace/newlines steps
Git worktrees:
hk install
fails
Automatic since v1.35.0; if using older version use
.hk-hooks/
+
core.hooksPath
Fix auto-stages wrong filesUse explicit
stage
glob on the step, or ensure step
glob
covers fixed files
Noisy output on successWrap commands in
scripts/quiet-on-success.sh
Hook runs in CI unnecessarilyAdd
[ -n "$CI" ] && exit 0
to
prepare
script
hk.local.pkl
uses amends not being honoured
First line must be
amends "./hk.pkl"

References

  • references/builtins-by-language.md
    — step selection by ecosystem
  • references/complete-examples.md
    — full hk.pkl configs for different stacks
  • assets/quiet-on-success.sh
    — copy into
    scripts/
    in target repo
  • hk docs — official documentation
  • hk builtins
    — list all 90+ available built-in linters