Built-in linters

Builtins are reusable Pkl step definitions for linters, formatters, and hk’s own utilities. They supply file patterns, check and fix commands, and optimizations such as diff output.

Install the tools separately. A builtin invokes executables from your environment; it does not install them. Use your project’s package manager or mise.

Use a builtin

amends "package://github.com/jdx/hk/releases/download/v2.0.1/hk@2.0.1#/Config.pkl"
import "package://github.com/jdx/hk/releases/download/v2.0.1/hk@2.0.1#/Builtins.pkl"

hooks {
  ["check"] {
    steps {
      ["prettier"] = Builtins.prettier
      ["eslint"] = Builtins.eslint
    }
  }
}

Builtins.prettier is the Pkl property name. The step name, "prettier", is your label for selecting the step in commands such as hk check --step prettier.

Keep the schema and Builtins imports on the same version. The catalogue below describes the version of the source used to build this website; an older pinned package may differ.

Customize a builtin

Amend a builtin to keep its defaults while changing specific properties:

["prettier"] = (Builtins.prettier) {
  glob = List("*.js", "*.ts", "*.json")
  exclude = List("**/generated/**")
  batch = false
}

A property assignment replaces that property. If you override glob or exclude, include every pattern you want to retain.

Use dependencies for ordering and profiles for optional checks:

["prettier"] = (Builtins.prettier) {
  depends = "eslint"
}
["mypy"] = (Builtins.mypy) {
  profiles = List("types")
}

Run the type checker with hk check --profile types. See configuration for groups, workspaces, and command templates.

Utilities included with hk

Steps such as Builtins.trailing_whitespace, Builtins.newlines, and Builtins.check_merge_conflict invoke hk util commands. These need no separate linter executable.

Tool availability

Builtins configure how hk invokes a tool; they do not install that tool. The executable used by the builtin must be on PATH, or the step must use a prefix that resolves it.

With HK_MISE=1, hk resolves the mise environment for the step's directory, so tools declared in a subproject's mise.toml are available without a prefix. For a Node tool installed locally by aube, prefix its builtin with aube exec:

["eslint"] = (Builtins.eslint) {
  prefix = List("aube", "exec")
}

Use an argv list for builtins backed by structured commands. A string prefix such as "aube exec" or "mise x --" cannot be combined with those commands.

Available builtins

The following catalogue is generated from the builtin definitions. Each entry includes the exact Pkl property to use. Refer to the source definitions for additional options and tests.

AsciiDoc

asciidoctor

Pkl: Builtins.asciidoctor

AsciiDoc syntax validator and processor

• Check: asciidoctor --failure-level=WARNING --out-file=/dev/null {{files}}

Build Systems

buildifier-format

Pkl: Builtins.buildifier_format

Formatter for Bazel BUILD, WORKSPACE, and Starlark files

• Glob: **/BUILD, **/BUILD.bazel, WORKSPACE, WORKSPACE.bazel, MODULE.bazel, **/*.bzl, **/*.star, **/*.sky
• Check: buildifier -mode=check {{files}}
• Fix: buildifier {{files}}

buildifier-lint

Pkl: Builtins.buildifier_lint

Linter for Bazel BUILD, WORKSPACE, and Starlark files

• Glob: **/BUILD, **/BUILD.bazel, WORKSPACE, WORKSPACE.bazel, MODULE.bazel, **/*.bzl, **/*.star, **/*.sky
• Check: buildifier -mode=check -lint=warn {{files}}
• Fix: buildifier -lint=fix {{files}}

CSS

stylelint

Pkl: Builtins.stylelint

CSS linter

• Glob: **/*.css, **/*.scss, **/*.sass, **/*.less
• Check: stylelint {{files}}
• Fix: stylelint --fix {{files}}

Configuration

sort-package-json

Pkl: Builtins.sort_package_json

Sort package.json keys

• Glob: **/package.json
• Check: sort-package-json --check {{files}}
• Fix: sort-package-json {{files}}

Data Formats

buf-format

Pkl: Builtins.buf_format

Protocol Buffers formatter

• Glob: **/*.proto
• Check (diff): buf format {{workspace}} --diff --exit-code
• Fix: buf format {{workspace}} --write

buf-lint

Pkl: Builtins.buf_lint

Protocol Buffers linter

• Glob: **/*.proto
• Check: buf lint {{workspace}}

jq

Pkl: Builtins.jq

JSON processor

• Glob: **/*.json

• Check (diff):

  failed=0
  for f in {{ files }}; do
  jq . "$f" | diff -u "$f" - || failed=1
  done
  exit $failed

• Fix:

  for f in {{ files }}; do
  tmp=$(mktemp) && jq -S . "$f" > "$tmp" && mv "$tmp" "$f"
  done

sql-fluff

Pkl: Builtins.sql_fluff

SQL linter and formatter

• Glob: **/*.sql
• Check: sqlfluff lint {{files}}
• Fix: sqlfluff fix {{files}}

taplo

Pkl: Builtins.taplo

TOML linter

• Glob: **/*.toml
• Check: taplo lint {{files}}

taplo-format

Pkl: Builtins.taplo_format

TOML formatter

• Glob: **/*.toml
• Check (diff): taplo format --check --diff {{files}}
• Fix: taplo format {{files}}

tombi

Pkl: Builtins.tombi

TOML linter

• Glob: **/*.toml
• Check: tombi lint --quiet {{files}}

tombi-format

Pkl: Builtins.tombi_format

TOML formatter

• Glob: **/*.toml
• Check (diff): tombi format --quiet --check --diff {{files}}
• Fix: tombi format --quiet {{files}}

xmllint

Pkl: Builtins.xmllint

XML validator

• Glob: **/*.xml
• Check: xmllint --noout {{files}}

yamlfmt

Pkl: Builtins.yamlfmt

YAML formatter

• Glob: **/*.yml, **/*.yaml
• Check (diff): yamlfmt -lint {{files}}
• Fix: yamlfmt {{files}}

yamllint

Pkl: Builtins.yamllint

YAML linter

• Glob: **/*.yml, **/*.yaml
• Check: yamllint --strict {{files}}

yq

Pkl: Builtins.yq

YAML processor

• Glob: **/*.yaml, **/*.yml

• Check (diff):

  failed=0
  for f in {{ files }}; do
  yq -P "$f" | diff -u "$f" - || failed=1
  done
  exit $failed

• Fix: yq -iP {{ files }}

EditorConfig

editorconfig-checker

Pkl: Builtins.editorconfig_checker

Validate files against EditorConfig rules

• Check: editorconfig-checker {{files}}

Elixir

mix-compile

Pkl: Builtins.mix_compile

Compile Elixir with Mix

• Glob: **/*.ex
• Check: mix compile --warnings-as-errors --strict-errors {{files}}

mix-fmt

Pkl: Builtins.mix_fmt

Format Elixir with Mix

• Glob: **/*.ex, **/*.exs
• Check: mix format --check-formatted {{files}}
• Fix: mix format {{files}}

mix-test

Pkl: Builtins.mix_test

Test Elixir with Mix

• Glob: **/*.ex, **/*.exs
• Check: mix test --warnings-as-errors {{files}}

Go

err-check

Pkl: Builtins.err_check

Error handling checker

• Glob: **/*.go
• Check: errcheck ./...

go-fix

Pkl: Builtins.go_fix

Go modernizer (requires Go 1.26+)

• Glob: **/*.go
• Check (diff): go fix -diff ./...
• Fix: go fix ./...

go-fmt

Pkl: Builtins.go_fmt

Go formatter

• Glob: **/*.go

• Check (diff):

  DIFF=$(gofmt -s -d {{files}})
  if [ -n "$DIFF" ]; then
  echo "$DIFF"
  exit 1
  fi

• Check (list files):

  FILES=$(gofmt -s -l {{files}})
  if [ -n "$FILES" ]; then
  echo "$FILES"
  exit 1
  fi

• Fix: gofmt -s -w {{files}}

go-fumpt

Pkl: Builtins.go_fumpt

Strict Go formatter

• Glob: **/*.go

• Check (diff): gofumpt -d {{files}}

• Check (list files):

  FILES=$(gofumpt -l {{files}})
  if [ -n "$FILES" ]; then
  echo "$FILES"
  exit 1
  fi

• Fix: gofumpt -w {{files}}

go-imports

Pkl: Builtins.go_imports

Go import management

• Glob: **/*.go

• Check (diff):

  DIFF=$(goimports -d {{files}})
  if [ -n "$DIFF" ]; then
  echo "$DIFF"
  exit 1
  fi

• Check (list files):

  FILES=$(goimports -l {{files}})
  if [ -n "$FILES" ]; then
  echo "$FILES"
  exit 1
  fi

• Fix: goimports -w {{files}}

go-lines

Pkl: Builtins.go_lines

Long line fixer

• Glob: **/*.go

• Check (list files):

  FILES=$(golines -l {{files}})
  if [ -n "$FILES" ]; then
  echo "$FILES"
  exit 1
  fi

• Fix: golines -w {{files}}

go-sec

Pkl: Builtins.go_sec

Security scanner

• Glob: **/*.go
• Check: gosec ./...

go-vet

Pkl: Builtins.go_vet

Go code vetting

• Glob: **/*.go
• Check: go vet ./...

go-vuln-check

Pkl: Builtins.go_vuln_check

Vulnerability scanner

• Glob: **/*.go
• Check: govulncheck ./...

golangci-lint

Pkl: Builtins.golangci_lint

Go meta-linter

• Glob: **/*.go
• Check: golangci-lint run --fix=false ./...
• Fix: golangci-lint run --fix ./...

golangci-lint-fmt

Pkl: Builtins.golangci_lint_fmt

Go formatter (part of golangci-lint)

• Glob: **/*.go
• Check (diff): golangci-lint fmt --diff {{files}}
• Fix: golangci-lint fmt {{files}}

gomod-tidy

Pkl: Builtins.gomod_tidy

Go module maintenance

• Glob: **/*.go, **/go.mod, **/go.sum
• Check (diff): go mod tidy -diff
• Fix: go mod tidy

revive

Pkl: Builtins.revive

Fast Go linter

• Glob: **/*.go
• Check: revive -set_exit_status ./...

staticcheck

Pkl: Builtins.staticcheck

Go static analysis

• Glob: **/*.go
• Check: staticcheck ./...

Infrastructure

actionlint

Pkl: Builtins.actionlint

GitHub Actions workflow linter

• Glob: .github/workflows/*.yml, .github/workflows/*.yaml
• Check: actionlint {{files}}

dclint

Pkl: Builtins.dclint

Docker Compose linter

• Glob: **/compose*.yml, **/compose*.yaml, **/docker-compose*.yml, **/docker-compose*.yaml
• Check: dclint {{files}}
• Fix: dclint --fix {{files}}

droast

Pkl: Builtins.droast

Dockerfile linter for security, layer hygiene, and best-practice violations

• Glob: **/Dockerfile, **/Dockerfile.*, **/*.Dockerfile, **/*.dockerfile, **/Containerfile, **/Containerfile.*
• Check: droast {{files}}
• Fix: droast --fix {{files}}

ghalint-action

Pkl: Builtins.ghalint_action

GitHub Actions action linter

• Glob: **/action.*
• Check: ghalint run-action {{files}}

ghalint-workflow

Pkl: Builtins.ghalint_workflow

GitHub Actions workflow linter

• Glob: .github/workflows/*
• Check: ghalint run

hadolint

Pkl: Builtins.hadolint

Dockerfile linter

• Glob: **/Dockerfile*
• Check: hadolint {{files}}

hclfmt

Pkl: Builtins.hclfmt

Hashicorp's hclfmt

• Glob: **/*.hcl
• Fix: hclfmt -w {{files}}

kubeconform

Pkl: Builtins.kubeconform

Kubernetes manifest validator

• Glob: **/k8s/**/*.yaml, **/k8s/**/*.yml, **/kubernetes/**/*.yaml, **/kubernetes/**/*.yml, **/manifests/**/*.yaml, **/manifests/**/*.yml, **/deploy/**/*.yaml, **/deploy/**/*.yml, **/deployments/**/*.yaml, **/deployments/**/*.yml
• Check: kubeconform -summary -strict -ignore-missing-schemas {{files}}

mise

Pkl: Builtins.mise

mise-en-place's built-in formatter and linter

• Glob: mise.toml, mise.*.toml, .mise.toml, .mise.*.toml, mise/config.toml, mise/config.*.toml, .mise/config.toml, .mise/config.*.toml, .config/mise.toml, .config/mise.*.toml, .config/mise/config.toml, .config/mise/config.*.toml, .config/mise/mise.toml, .config/mise/mise.*.toml, .config/mise/conf.d/*.toml
• Check: mise fmt --check
• Fix: mise fmt

pinact

Pkl: Builtins.pinact

Pin GitHub Actions to commit SHA for security

• Glob: .github/workflows/*, **/action.*
• Check (diff): pinact run --verify-comment --check {{files}}
• Fix: pinact run --verify-comment {{files}}

pinact-update

Pkl: Builtins.pinact_update

Pin GitHub Actions to update actions to latest versions

• Glob: .github/workflows/*, **/action.*
• Check (diff): pinact run --update --verify-comment --check {{files}}
• Fix: pinact run --update --verify-comment {{files}}

terraform

Pkl: Builtins.terraform

Terraform formatter

• Glob: **/*.tf, **/*.tfvars, **/*.tftest.hcl
• Check (list files): terraform fmt -check {{files}}
• Fix: terraform fmt {{files}}

terraform-docs

Pkl: Builtins.terraform_docs

Terraform module documentation generator

• Glob: **/*.tf, **/*.tofu, **/.terraform.lock.hcl

• Check:

  for f in {{ files }}; do dirname "$f"; done | sort -u | { code=0; while IFS= read -r dir; do
  terraform-docs markdown table --output-check --output-file README.md --output-mode inject "$dir" || code=1
  done; exit $code; }

• Fix:

  for f in {{ files }}; do dirname "$f"; done | sort -u | { code=0; while IFS= read -r dir; do
  terraform-docs markdown table --output-file README.md --output-mode inject "$dir" || code=1
  done; exit $code; }

terraform-validate

Pkl: Builtins.terraform_validate

Terraform configuration validator

• Glob: **/*.tf, **/*.tfvars, **/*.tf.json, **/*.tofu, **/.terraform.lock.hcl

• Check:

  for f in {{ files }}; do dirname "$f"; done | sort -u | { code=0; while IFS= read -r dir; do
  terraform -chdir="$dir" validate && continue
  terraform -chdir="$dir" init -backend=false -input=false > /dev/null || { code=1; continue; }
  terraform -chdir="$dir" validate || code=1
  done; exit $code; }

terragrunt-hcl-fmt

Pkl: Builtins.terragrunt_hcl_fmt

Terragrunt HCL formatter

• Glob: **/*.hcl

• Check:

  set --
  for f in {{ files }}; do set -- "$@" "--filter=./$f"; done
  if [ "$#" -eq 0 ]; then exit 0; fi
  terragrunt hcl fmt --check --diff "$@"

• Fix:

  set --
  for f in {{ files }}; do set -- "$@" "--filter=./$f"; done
  if [ "$#" -eq 0 ]; then exit 0; fi
  terragrunt hcl fmt "$@"

terragrunt-hcl-validate

Pkl: Builtins.terragrunt_hcl_validate

Terragrunt HCL validator

• Glob: **/*.hcl

• Check:

  set --
  for f in {{ files }}; do
  case "$f" in */*) d="./${f%/*}" ;; *) d="." ;; esac
  set -- "$@" "--filter=$d" "--filter=reading=./$f"
  done
  if [ "$#" -eq 0 ]; then exit 0; fi
  terragrunt hcl validate --show-config-path --log-level error "$@"

tf-lint

Pkl: Builtins.tf_lint

Terraform linter

• Glob: **/*.tf, **/*.tfvars, **/*.tofu

• Check:

  for f in {{ files }}; do dirname "$f"; done | sort -u | { code=0; while IFS= read -r dir; do
  tflint --chdir="$dir" || code=1
  done; exit $code; }

• Fix:

  for f in {{ files }}; do dirname "$f"; done | sort -u | { code=0; while IFS= read -r dir; do
  tflint --chdir="$dir" --fix || tflint --chdir="$dir" || code=1
  done; exit $code; }

tofu

Pkl: Builtins.tofu

OpenTofu formatter

• Glob: **/*.tf, **/*.tfvars, **/*.tftest.hcl
• Check (list files): tofu fmt -check {{files}}
• Fix: tofu fmt {{files}}

zizmor

Pkl: Builtins.zizmor

GitHub Actions security static analysis tool

• Glob: .github/workflows/*.yml, .github/workflows/*.yaml, .github/dependabot.yml, **/action.yml, **/action.yaml
• Check: zizmor --no-progress {{files}}
• Check (diff): zizmor --no-progress {{files}}
• Fix: zizmor --no-progress --fix {{files}}

Java

google-java-format

Pkl: Builtins.google_java_format

Google Java Format

• Glob: **/*.java
• Check: google-java-format --dry-run --set-exit-if-changed {{files}}
• Check (list files): google-java-format --dry-run {{files}}
• Fix: google-java-format --replace {{files}}

JavaScript/TypeScript

biome

Pkl: Builtins.biome

Fast formatter and linter

• Glob: **/*.js, **/*.jsx, **/*.ts, **/*.tsx, **/*.json
• Check: biome check --no-errors-on-unmatched {{files}}
• Fix: biome check --write --no-errors-on-unmatched {{files}}

deno

Pkl: Builtins.deno

Deno formatter

• Glob: **/*.js, **/*.jsx, **/*.ts, **/*.tsx
• Check: deno fmt --check {{files}}
• Fix: deno fmt {{files}}

deno-check

Pkl: Builtins.deno_check

Deno type checker

• Glob: **/*.js, **/*.jsx, **/*.ts, **/*.tsx
• Check: deno check {{files}}

eslint

Pkl: Builtins.eslint

Pluggable JavaScript linter

• Glob: **/*.js, **/*.jsx, **/*.ts, **/*.tsx
• Check: eslint {{files}}
• Fix: eslint --fix {{files}}

knip

Pkl: Builtins.knip

Find unused files, dependencies, and exports

• Check: knip --no-progress --directory {{workspace}}
• Fix: knip --fix --no-progress --directory {{workspace}}

ox-lint

Pkl: Builtins.ox_lint

Oxidation compiler linter

• Glob: **/*.js, **/*.mjs, **/*.cjs, **/*.ts, **/*.mts, **/*.cts, **/*.jsx, **/*.tsx, **/*.vue, **/*.svelte, **/*.astro
• Check: oxlint --deny-warnings {{files}}
• Fix: oxlint --deny-warnings --fix {{files}}

oxfmt

Pkl: Builtins.oxfmt

Fast Rust-powered code formatter (Prettier compatible)

• Glob: **/*.js, **/*.mjs, **/*.cjs, **/*.ts, **/*.mts, **/*.cts, **/*.jsx, **/*.tsx, **/*.mdx, **/*.vue, **/*.json, **/*.jsonc, **/*.json5, **/*.yaml, **/*.yml, **/*.toml, **/*.md, **/*.markdown, **/*.html, **/*.htm, **/*.css, **/*.scss, **/*.less, **/*.graphql, **/*.gql, **/*.handlebars, **/*.hbs
• Check: oxfmt --check --no-error-on-unmatched-pattern {{files}}
• Check (list files): oxfmt --list-different --no-error-on-unmatched-pattern {{files}}
• Fix: oxfmt --write --no-error-on-unmatched-pattern {{files}}

prettier

Pkl: Builtins.prettier

Opinionated code formatter

• Glob: **/*.js, **/*.jsx, **/*.mjs, **/*.cjs, **/*.ts, **/*.tsx, **/*.mts, **/*.cts, **/*.css, **/*.scss, **/*.less, **/*.html, **/*.json, **/*.json5, **/*.jsonc, **/*.yaml, **/*.yml, **/*.markdown, **/*.markdown.mdx, **/*.md, **/*.graphql, **/*.handlebars, **/*.svelte, **/*.astro, **/*.htmlangular, **/*.vue
• Check: prettier --check {{files}}
• Check (list files): prettier --list-different {{files}}
• Fix: prettier --write {{files}}

sherif

Pkl: Builtins.sherif

Opinionated, zero-config linter for TypeScript & JavaScript monorepos

• Glob: **/package.json, **/pnpm-workspace.yaml
• Check: sherif
• Fix: sherif --fix --no-install

standard-js

Pkl: Builtins.standard_js

JavaScript Standard Style

• Glob: **/*.js, **/*.jsx, **/*.ts, **/*.tsx
• Check: standard {{files}}
• Fix: standard --fix {{files}}

tsc

Pkl: Builtins.tsc

TypeScript type checker

• Glob: **/*.ts, **/*.tsx
• Check: tsc --noEmit -p {{workspace_indicator}}

tsserver

Pkl: Builtins.tsserver

TypeScript language server diagnostics

• Glob: **/*.ts, **/*.tsx
• Check: tsc-files --noEmit {{files}}

vp-check

Pkl: Builtins.vp_check

Formats, lints, and type checks code together

• Glob: **/*.js, **/*.mjs, **/*.cjs, **/*.ts, **/*.mts, **/*.cts, **/*.jsx, **/*.tsx, **/*.mdx, **/*.vue, **/*.svelte, **/*.astro, **/*.json, **/*.jsonc, **/*.json5, **/*.yaml, **/*.yml, **/*.md, **/*.markdown, **/*.html, **/*.htm, **/*.css, **/*.scss, **/*.less, **/*.graphql, **/*.gql, **/*.handlebars, **/*.hbs, **/*.toml
• Check: vp check {{files}}
• Fix: vp check --fix {{files}}

vp-fmt

Pkl: Builtins.vp_fmt

Formats code with Oxfmt

• Glob: **/*.js, **/*.mjs, **/*.cjs, **/*.ts, **/*.mts, **/*.cts, **/*.jsx, **/*.tsx, **/*.mdx, **/*.vue, **/*.json, **/*.jsonc, **/*.json5, **/*.yaml, **/*.yml, **/*.toml, **/*.md, **/*.markdown, **/*.html, **/*.htm, **/*.css, **/*.scss, **/*.less, **/*.graphql, **/*.gql, **/*.handlebars, **/*.hbs
• Check: vp fmt --check {{files}}
• Check (list files): vp fmt --list-different {{files}}
• Fix: vp fmt {{files}}

vp-lint

Pkl: Builtins.vp_lint

Lints code with OxLint

• Glob: **/*.js, **/*.mjs, **/*.cjs, **/*.ts, **/*.mts, **/*.cts, **/*.jsx, **/*.tsx, **/*.mdx, **/*.vue, **/*.svelte, **/*.astro
• Check: vp lint --deny-warnings {{files}}
• Fix: vp lint --deny-warnings --fix {{files}}

xo

Pkl: Builtins.xo

JavaScript/TypeScript linter with great defaults

• Glob: **/*.js, **/*.jsx, **/*.ts, **/*.tsx
• Check: xo {{files}}
• Fix: xo --fix {{files}}

Lua

luacheck

Pkl: Builtins.luacheck

Lua linter

• Check: luacheck {{files}}

selene

Pkl: Builtins.selene

Lua linter

• Check (diff): selene {{files}}

stylua

Pkl: Builtins.stylua

Lua formatter

• Check (diff): stylua --check {{files}}
• Fix: stylua {{files}}

Markdown

contextlint

Pkl: Builtins.contextlint

Rule-based linter for structured Markdown documents

• Check: contextlint {{files}}

mado

Pkl: Builtins.mado

Fast Markdown linter (CommonMark/GFM)

• Check: mado check {{files}}

markdown-lint

Pkl: Builtins.markdown_lint

Markdown linter

• Glob: **/*.md, **/*.markdown
• Check: markdownlint {{files}}
• Fix: markdownlint --fix {{files}}

mdschema

Pkl: Builtins.mdschema

Schema-based Markdown documentation validator

• Check: mdschema check {{files}}

rumdl

Pkl: Builtins.rumdl

Markdown linter

• Glob: **/*.md, **/*.markdown
• Check: rumdl check {{files}}
• Check (diff): rumdl check --diff {{files}}
• Fix: rumdl check --fix {{files}}

rumdl-format

Pkl: Builtins.rumdl_format

Markdown formatter

• Glob: **/*.md, **/*.markdown
• Check (diff): rumdl fmt --check --diff {{files}}
• Fix: rumdl fmt {{files}}

ryl-markdown

Pkl: Builtins.ryl_markdown

Lint YAML embedded in Markdown (front matter + fenced yaml blocks) with ryl

• Check: ryl --markdown {{files}}
• Check (diff): ryl --diff --markdown {{files}}
• Check (list files): ryl --list-files --markdown {{files}}
• Fix: ryl --fix --markdown {{files}}

Nix

alejandra

Pkl: Builtins.alejandra

Alternative Nix formatter

• Glob: **/*.nix
• Check: alejandra --check {{files}}
• Fix: alejandra {{files}}

deadnix

Pkl: Builtins.deadnix

Scan Nix files for dead code

• Glob: **/*.nix
• Check: deadnix --fail {{files}}
• Fix: deadnix --edit {{files}}

nil

Pkl: Builtins.nil

Nix Language server

• Glob: **/*.nix
• Check: nil diagnostics --deny-warnings {{files}}

nix-fmt

Pkl: Builtins.nix_fmt

Nix formatter

• Glob: **/*.nix

nixf-diagnose

Pkl: Builtins.nixf_diagnose

Nix linter based on libnixf

• Glob: **/*.nix
• Check: nixf-diagnose {{files}}

nixpkgs-format

Pkl: Builtins.nixpkgs_format

Nixpkgs formatter

• Glob: **/*.nix
• Check: nixpkgs-fmt --check {{files}}
• Fix: nixpkgs-fmt {{files}}

Other Languages

astro

Pkl: Builtins.astro

Astro component checker

• Glob: **/*.astro
• Check: astro check {{files}}

clang-format

Pkl: Builtins.clang_format

C/C++ formatter

• Glob: **/*.c, **/*.h, **/*.cpp, **/*.hpp, **/*.cc, **/*.hh, **/*.cxx, **/*.hxx
• Check: clang-format --dry-run -Werror {{files}}
• Fix: clang-format -i {{files}}

cmake-format

Pkl: Builtins.cmake_format

Source code formatter for cmake listfiles

• Glob: **/CMakeLists.txt, **/*.cmake
• Check: cmake-format --check {{files}}
• Fix: cmake-format --in-place {{files}}

cpp-lint

Pkl: Builtins.cpp_lint

C++ style checker

• Glob: **/*.c, **/*.h, **/*.cpp, **/*.hpp, **/*.cc, **/*.hh, **/*.cxx, **/*.hxx
• Check: cpplint {{files}}

dprint

Pkl: Builtins.dprint

Pluggable code formatter

• Check: dprint check --allow-no-files {{files}}
• Check (list files): dprint check --allow-no-files --list-different {{files}}
• Fix: dprint fmt --allow-no-files {{files}}

ktlint

Pkl: Builtins.ktlint

Kotlin linter and formatter

• Glob: **/*.kt
• Check: ktlint {{files}}
• Fix: ktlint -F {{files}}

swiftlint

Pkl: Builtins.swiftlint

Swift style and conventions

• Glob: **/*.swift
• Check: swiftlint lint {{files}}
• Fix: swiftlint --fix {{files}}

vacuum

Pkl: Builtins.vacuum

Fast OpenAPI linter

• Glob: **/*openapi*.yaml, **/*openapi*.yml, **/*openapi*.json, **/*swagger*.yaml, **/*swagger*.yml, **/*swagger*.json
• Check: vacuum lint {{files}}
• Fix: vacuum lint --fix {{files}}

PHP

php-cs

Pkl: Builtins.php_cs

PHP coding standards

• Glob: **/*.php
• Check: phpcs {{files}}
• Fix: phpcbf {{files}}

Package

aqua-update-checksum

Pkl: Builtins.aqua_update_checksum

create or update aqua checksums

• Glob: {aqua,.aqua}.{yml,yaml}, {aqua,.aqua}/**/*.{yml,yaml}, aqua-checksums.json, {aqua,.aqua}/aqua-checksums.json
• Fix: aqua update-checksum --prune

Pkl

pkl

Pkl: Builtins.pkl

Pkl configuration language

• Check: pkl eval {{files}} >/dev/null

pkl-format

Pkl: Builtins.pkl_format

Pkl formatter

• Check (list files): pkl format --diff-name-only {{ files }}

• Fix:

  pkl format --write {{ files }}
  code=$?
  if [ $code -eq 11 ]; then
  exit 0
  else
  exit $code
  fi

Python

black

Pkl: Builtins.black

Opinionated Python formatter

• Glob: **/*.py
• Check (diff): black --check --diff {{files}}
• Fix: black {{files}}

flake8

Pkl: Builtins.flake8

Python style guide enforcement

• Glob: **/*.py
• Check: flake8 {{files}}

isort

Pkl: Builtins.isort

Python import sorter

• Glob: **/*.py
• Check: isort --check-only {{files}}
• Fix: isort {{files}}

mypy

Pkl: Builtins.mypy

Static type checker for Python

• Glob: **/*.py, **/*.pyi
• Check: mypy {{files}}

pylint

Pkl: Builtins.pylint

Python code analysis

• Glob: **/*.py
• Check: pylint {{files}}

python-check-ast

Pkl: Builtins.python_check_ast

Validate Python syntax by parsing the AST

• Glob: **/*.py
• Check: hk util python-check-ast {{files}}

python-debug-statements

Pkl: Builtins.python_debug_statements

Detect debug statements in Python code

• Glob: **/*.py
• Check: hk util python-debug-statements {{files}}

ruff

Pkl: Builtins.ruff

Fast Python linter

• Check: ruff check --force-exclude {{files}}
• Fix: ruff check --force-exclude --fix {{files}}

ruff-format

Pkl: Builtins.ruff_format

Fast Python formatter (part of ruff)

• Check (diff): ruff format --quiet --force-exclude --diff {{files}}
• Fix: ruff format --quiet --force-exclude {{files}}

ty

Pkl: Builtins.ty

Fast Python type checker

• Glob: **/*.py, **/*.pyi
• Check: ty check {{files}}

Ruby

brakeman

Pkl: Builtins.brakeman

Security scanner for Rails

• Check: brakeman -q -w2 {{files}}

bundle-audit

Pkl: Builtins.bundle_audit

Dependency security audit

• Glob: **/Gemfile.lock
• Check: bundle-audit check {{files}}
• Fix: bundle-audit update

erb

Pkl: Builtins.erb

ERB template linter

• Glob: **/*.erb
• Check: erb -P -x -T - {{ files }} | ruby -c

fasterer

Pkl: Builtins.fasterer

Performance suggestions

• Check: fasterer {{files}}

reek

Pkl: Builtins.reek

Code smell detector

• Check: reek {{files}}

rubocop

Pkl: Builtins.rubocop

Ruby style guide

• Glob: **/*.rb, **/*.arb, **/*.axlsx, **/*.builder, **/*.gemfile, **/*.gemspec, **/*.jb, **/*.jbuilder, **/*.mspec, **/*.opal, **/*.pluginspec, **/*.podspec, **/*.rabl, **/*.rake, **/*.rbw, **/*.ru, **/*.ruby, **/*.schema, **/*.spec, **/*.thor, **/.irbrc, **/.pryrc, **/.simplecov, **/buildfile, **/Appraisals, **/Berksfile, **/Brewfile, **/Buildfile, **/Capfile, **/Dangerfile, **/Deliverfile, **/Fastfile, **/*Fastfile, **/Gemfile, **/Guardfile, **/Jarfile, **/Mavenfile, **/Podfile, **/Puppetfile, **/Rakefile, **/rakefile, **/Schemafile, **/Snapfile, **/Steepfile, **/Thorfile, **/Vagrantfile
• Check: rubocop --force-exclusion {{files}}
• Check (list files): rubocop --force-exclusion --format files {{files}}
• Fix: rubocop --force-exclusion --autocorrect {{files}}

rubocop-server

Pkl: Builtins.rubocop_server

Ruby style guide (using RuboCop's --server mode)

• Glob: **/*.rb, **/*.arb, **/*.axlsx, **/*.builder, **/*.gemfile, **/*.gemspec, **/*.jb, **/*.jbuilder, **/*.mspec, **/*.opal, **/*.pluginspec, **/*.podspec, **/*.rabl, **/*.rake, **/*.rbw, **/*.ru, **/*.ruby, **/*.schema, **/*.spec, **/*.thor, **/.irbrc, **/.pryrc, **/.simplecov, **/buildfile, **/Appraisals, **/Berksfile, **/Brewfile, **/Buildfile, **/Capfile, **/Dangerfile, **/Deliverfile, **/Fastfile, **/*Fastfile, **/Gemfile, **/Guardfile, **/Jarfile, **/Mavenfile, **/Podfile, **/Puppetfile, **/Rakefile, **/rakefile, **/Schemafile, **/Snapfile, **/Steepfile, **/Thorfile, **/Vagrantfile
• Check: rubocop --server --force-exclusion {{files}}
• Check (list files): rubocop --server --force-exclusion --format files {{files}}
• Fix: rubocop --server --force-exclusion --autocorrect {{files}}

sorbet

Pkl: Builtins.sorbet

Type checker for Ruby

• Check: srb tc {{files}}

standard-rb

Pkl: Builtins.standard_rb

Ruby Standard Style

• Check: standardrb {{files}}
• Fix: standardrb --fix {{files}}

Rust

cargo-check

Pkl: Builtins.cargo_check

Fast Rust type checking

• Glob: **/*.rs
• Check: cargo check --quiet
• Fix: cargo fix --allow-dirty --allow-staged --quiet

cargo-clippy

Pkl: Builtins.cargo_clippy

Rust linter

• Glob: **/*.rs
• Check: cargo clippy --manifest-path {{workspace_indicator}} --quiet
• Fix: cargo clippy --manifest-path {{workspace_indicator}} --fix --allow-dirty --allow-staged --quiet

cargo-deny

Pkl: Builtins.cargo_deny

Rust dependency linter

• Glob: **/Cargo.toml, **/Cargo.lock, **/deny.toml, **/.deny.toml, **/deny.exceptions.toml, **/.deny.exceptions.toml
• Check: cargo-deny --locked --workspace check

cargo-fmt

Pkl: Builtins.cargo_fmt

Rust code formatter

• Glob: **/*.rs
• Check: cargo fmt --check --manifest-path {{workspace_indicator}}
• Check (list files): cargo fmt --check --manifest-path {{workspace_indicator}} -- --files-with-diff
• Fix: cargo fmt --manifest-path {{workspace_indicator}}

rustfmt

Pkl: Builtins.rustfmt

Rust code formatter (standalone)

• Glob: **/*.rs
• Check: rustfmt --check --edition 2024 {{files}}
• Check (list files): rustfmt --check --edition 2024 --files-with-diff {{files}}
• Fix: rustfmt --edition 2024 {{files}}

Secrets

betterleaks

Pkl: Builtins.betterleaks

A Better Secrets Scanner built for configurability and speed

• Check: betterleaks dir --redact --verbose --no-banner {{files}}

gitleaks

Pkl: Builtins.gitleaks

Secret scanner for repository working trees

• Check: gitleaks dir --redact --verbose --no-banner .

kingfisher

Pkl: Builtins.kingfisher

Secret scanner with live validation and 1,000+ rules

• Check: kingfisher scan {{files}} --no-update-check --no-validate --quiet

Shell

shellcheck

Pkl: Builtins.shellcheck

Shell script analyzer

• Check: shellcheck {{files}}
• Check (diff): shellcheck --format=diff {{files}}

shellharden

Pkl: Builtins.shellharden

The corrective bash syntax highlighter

• Check: shellharden --check {{files}}
• Fix: shellharden --replace {{files}}

shfmt

Pkl: Builtins.shfmt

Shell formatter

• Check (diff): shfmt -d --apply-ignore {{ files }}

• Check (list files):

  files=$(shfmt -l --apply-ignore {{ files }})
  if [ -n "$files" ]; then
  echo "$files"
  exit 1
  fi

• Fix: shfmt -w --apply-ignore {{ files }}

Special Purpose

byte-order-marker

Pkl: Builtins.byte_order_marker

Detect UTF-8 BOM

• Check (diff): hk util check-byte-order-marker --diff {{files}}
• Fix: hk util fix-byte-order-marker {{files}}

check-added-large-files

Pkl: Builtins.check_added_large_files

Prevent committing large files

• Glob: **/*
• Check: hk util check-added-large-files {{files}}

check-case-conflict

Pkl: Builtins.check_case_conflict

Detect case-insensitive filename conflicts

• Glob: **/*
• Check: hk util check-case-conflict {{files}}

check-conventional-commit

Pkl: Builtins.check_conventional_commit

Verify commit message matches conventional commits formatting

• Check: hk util check-conventional-commit {{commit_msg_file}}

check-executables-have-shebangs

Pkl: Builtins.check_executables_have_shebangs

Verify executable files have shebang lines

• Check: hk util check-executables-have-shebangs {{files}}

check-merge-conflict

Pkl: Builtins.check_merge_conflict

Detect merge conflict markers

• Check: hk util check-merge-conflict --assume-in-merge {{files}}

check-shebang-scripts-are-executable

Pkl: Builtins.check_shebang_scripts_are_executable

Verify files with shebang lines are executable

• Check: hk util check-shebang-scripts-are-executable {{files}}

check-symlinks

Pkl: Builtins.check_symlinks

Detect broken symlinks

• Glob: **/*
• Check: hk util check-symlinks {{files}}

cocogitto-commit-msg

Pkl: Builtins.cocogitto_commit_msg

Conventional commits linter

• Check: cog --quiet verify --file {{commit_msg_file}}

destroyed-symlinks

Pkl: Builtins.destroyed_symlinks

Detect symlinks replaced by regular files holding their target path

• Check: hk util destroyed-symlinks

detect-private-key

Pkl: Builtins.detect_private_key

Detect accidentally committed private keys

• Check: hk util detect-private-key {{files}}

fix-smart-quotes

Pkl: Builtins.fix_smart_quotes

Replace smart quotes with regular quotes

• Check (diff): hk util fix-smart-quotes --diff {{files}}
• Fix: hk util fix-smart-quotes {{files}}

forbid-submodules

Pkl: Builtins.forbid_submodules

Forbid git submodules in the repository

• Check: hk util forbid-submodules

harper

Pkl: Builtins.harper

Grammar checker for prose and documentation

• Check: harper-cli lint {{files}}

harper-commit-message

Pkl: Builtins.harper_commit_message

Grammar checker for commit message

• Check: harper-cli lint {{commit_msg_file}}

hk-test

Pkl: Builtins.hk_test

Run step-defined hk's tests

• Glob: hk.pkl, .config/hk.pkl
• Check: hk test --quiet

just-format

Pkl: Builtins.just_format

Justfile formatter

• Glob: **/justfile, **/*.just

• Fix:

  xargs -d'
  ' -I {} -- just --fmt --unstable --justfile {}

ls-lint

Pkl: Builtins.ls_lint

Directory and filename naming linter

• Glob: **/*
• Check: ls-lint

lychee

Pkl: Builtins.lychee

Fast, async, stream-based link checker

• Check: lychee --no-progress {{files}}

mixed-line-ending

Pkl: Builtins.mixed_line_ending

Detect and fix mixed line endings

• Check (diff): hk util mixed-line-ending --diff {{files}}
• Fix: hk util mixed-line-ending --fix {{files}}

newlines

Pkl: Builtins.newlines

Ensure files end with newline

• Check (diff): hk util end-of-file-fixer --diff {{files}}
• Fix: hk util end-of-file-fixer --fix {{files}}

no-commit-to-branch

Pkl: Builtins.no_commit_to_branch

Prevent direct commits to protected branches

• Check: hk util no-commit-to-branch

textlint

Pkl: Builtins.textlint

Pluggable natural language linter

• Glob: **/*.md, **/*.markdown, **/*.txt
• Check: textlint {{files}}
• Fix: textlint --fix {{files}}

trailing-whitespace

Pkl: Builtins.trailing_whitespace

Detect and remove trailing whitespace

• Check (diff): hk util trailing-whitespace --diff {{files}}
• Fix: hk util trailing-whitespace --fix {{files}}

typos

Pkl: Builtins.typos

Source code spell checker

• Check (diff):

  output=$(typos --force-exclude --diff {{files}})
  [ -z "$output" ] && exit 0
  printf "%s" "$output"
  exit 1

• Fix: typos --force-exclude --write-changes {{ files }}

vale

Pkl: Builtins.vale

Prose linter for markup and code comments

• Check: vale sync && vale {{ files }}

YAML

ryl

Pkl: Builtins.ryl

Re-implementation of yamllint in Rust

• Check: ryl {{files}}
• Check (diff): ryl --diff {{files}}
• Check (list files): ryl --list-files {{files}}
• Fix: ryl --fix {{files}}

Add a tool of your own

If there is no builtin, define a step with glob, check, and an optional fix command. Only enable batching if the tool can process independent subsets of files correctly.

See custom steps for a complete example, or contributing to contribute a reusable definition.