peachycheck

One peachycheck.yml per repository runs the native linters (ruff, pyright, eslint, clang-tidy, clang-format, vale, doc8, codespell, j2lint, gitleaks) and the hooks that apply them while Claude Code or Codex works. It only checks: builds and tests stay in the repository's own CI. Locally, in the agents' hooks and in CI it is the same command with the same configuration, so a change that passes one passes all.

Why: every repository otherwise grows its own mix of pre-commit hooks, CI steps and editor settings that drift apart. peachycheck keeps the shared part in one file an organization publishes, and each repository EXTENDS it, overriding only what it must.

• No opinions. peachycheck only knows how to run and read each linter; every linter runs with its own defaults until an organization or a repository configures it.
• Native linters, native inheritance. Each linter reads its own configuration file. sync writes an organization's base configurations into .peachycheck/; the repository's own ruff.toml, pyrightconfig.json or eslint.config.mjs extends them and adds only its deviations. A finding names the linter, its rule and the rule's documentation.
• Per file. Each file belongs to the nearest folder above it with a peachycheck.yml, and is judged by that repository's configuration; one edit or one lint may span repositories.
• Finding-free. Every finding fails; there is no baseline. On a pull request only the changed files count, on the default branch every file.

Languages

• Python (.py): ruff, ruff format, pyright
• C++ (.cpp, .cc, .cxx, .hpp, .hh, .h, .tpp, .ipp): clang-tidy, clang-format
• TypeScript (.ts, .tsx): ESLint
• reStructuredText (.rst): doc8, vale, codespell
• Jinja (.j2, .jinja, .jinja2): j2lint
• Secrets (every file): gitleaks
• LaTeX (.tex)

Install

uv tool install peachycheck     # or: pipx install peachycheck
peachycheck --version
peachycheck install             # download the pinned vale and gitleaks
peachycheck hooks install       # lint after each edit and before Claude/Codex stop

ruff, codespell, doc8, clang-tidy, clang-format, j2lint and pyright are pinned dependencies (pyright uses Node from PATH or installs it); vale and gitleaks are downloaded into ~/.cache/peachycheck/bin, checked against their sha256 (Linux x64); eslint is the repository's own (node_modules).

Set a repository up

peachycheck init [--extends URL]    # once per repository
peachycheck upgrade [--to 0.2.0]    # later: move it to another version

init prints what it did; run again, it changes nothing:

1. peachycheck.yml, extending --extends (your organization's file, if any) and pinning PEACHYCHECK_VERSION: the installed release, or the installed commit for a git install;
2. .github/workflows/peachycheck.yml, a job that runs the action below (passing SUBMODULES_TOKEN when the repository has a .gitmodules);
3. the base configurations in .peachycheck/ (sync) and, where the repository has none, its own ruff.toml, pyrightconfig.json or eslint.config.mjs holding just the line that extends the base;
4. the pinned vale and gitleaks (install);
5. for a Python project with a pyproject.toml, peachycheck==<version> in the dev dependency group (uv add --dev), when installed from PyPI.

upgrade moves PEACHYCHECK_VERSION, the refs of the action and the reusable workflow in .github/workflows/ and an existing dev pin to the installed version (or --to VERSION) and syncs the configurations again.

CI

The action (action.yml) is the check as one step of a job:

jobs:
  peachycheck:
    runs-on: ubuntu-latest
    steps:
      - uses: drexlerd/peachycheck@v0.1.0
        # with:
        #   version: 0.1.0                          # see below
        #   token: ${{ secrets.SUBMODULES_TOKEN }}  # private submodules
        #   prepare: npm ci                         # what the linters need

The reusable workflow does the same in three lines:

jobs:
  peachycheck:
    uses: drexlerd/peachycheck/.github/workflows/check.yml@v0.1.0
    secrets: inherit

It checks the repository out and installs peachycheck: the version input, else the repository's PEACHYCHECK_VERSION, else the action's own code (so @<commit> installs that commit). A version such as 0.1.0 comes from PyPI, anything else is a git ref of this repository. Then it fails when

1. a tool configuration differs from what the configuration shares (sync --check),
2. a linter finds anything in a changed file (lint --base), or anywhere on a push to the default branch (lint --all).

It checks out submodules (private ones need the token) and runs prepare, if given, before the linters: what they need, such as npm ci for ESLint or a CMake configure that writes compile_commands.json for clang-tidy. It builds and tests nothing; that is the repository's own CI. An organization can wrap the action in a reusable workflow of its own that pins one peachycheck for all its repositories; a job that runs the action keeps its name, so a required status check stays the same.

Locally

peachycheck sync [--check] # write (or compare) .peachycheck/, the base configurations
peachycheck lint [--fix]   # findings in files changed since the merge base
peachycheck lint --all     # findings anywhere
peachycheck lint FILE...   # findings in these files

Configuration

A repository's peachycheck.yml extends peachycheck's defaults (src/peachycheck/defaults/peachycheck.yml), then the files it EXTENDS, then its own keys, in MegaLinter's style:

EXTENDS: https://raw.githubusercontent.com/my-org/standards/<commit>/peachycheck.yml
PEACHYCHECK_VERSION: 0.1.0
DISABLE_LINTERS: [SPELL_VALE]
FILTER_REGEX_EXCLUDE: ^vendor/
PYTHON_RUFF_ARGUMENTS: [--preview]

• Merging. Later files win, mappings merge key by key, and the keys CONFIG_PROPERTIES_TO_APPEND names append their lists. EXTENDS takes a path or URL, or a list of them; a relative one resolves against the file that names it.
• Paths. The sources of FILES are paths relative to the file that names them. A file extended by its GitHub raw URL (https://raw.githubusercontent.com/<owner>/<repo>/<ref>/<path>) is read from a snapshot of that repository at that ref, cached in ~/.cache/peachycheck/extends/, so an organization's folders (rules, Vale styles) resolve too. Pin a commit or tag: a cached ref is never fetched again. Other URLs work for single files without relative paths.
• Selecting linters. ENABLE_LINTERS (only these), DISABLE_LINTERS, FILTER_REGEX_EXCLUDE (a path regex for every linter) and, per linter, <LINTER>_FILTER_REGEX_INCLUDE, <LINTER>_FILTER_REGEX_EXCLUDE and <LINTER>_ARGUMENTS (appended to its command).

Base and overrides

FILES names the files sync writes into the repository's .peachycheck/ folder: those under general for every repository, those under a marker file (such as pyproject.toml or package.json) for each repository that has it; a later entry wins, and a folder, such as Vale's styles, brings every file below it.

FILES:
  general: {.vale.ini: rules/.vale.ini}
  pyproject.toml: {ruff.toml: rules/ruff.toml}
  CMakeLists.txt: {.clang-tidy: rules/.clang-tidy}
``` The folder is
generated and committed, so editors and CI read it offline; `sync --check`
fails when it differs. A base file is read from `.peachycheck/`, so its
paths start there: `"../**/tests/**"` for ruff's per-file ignores,
`"extraPaths": ["../src"]` for pyright.

A repository overrides a base setting in its own configuration, which
inherits the base natively:

| tool | the repository's own file |
|---|---|
| ruff | `ruff.toml` (or `[tool.ruff]`): `extend = ".peachycheck/ruff.toml"` |
| pyright | `pyrightconfig.json`: `"extends": ".peachycheck/pyrightconfig.json"` |
| ESLint | `eslint.config.mjs`: `import base from "./.peachycheck/eslint.config.mjs"; export default [...base, ...]` |
| Vale | `.vale.ini` with `StylesPath = .peachycheck/styles` and the base's styles |
| clang-tidy | `.clang-tidy` with deviations only: `lint` lays it over the base (`Checks` joined, `CheckOptions` merged) |

A linter gets the repository's own file, else the base, else none: then
it runs with its defaults, or, for Vale and ESLint, which cannot run
without a configuration, it is skipped. Coarse switches stay in
`peachycheck.yml`: `DISABLE_LINTERS`, `<LINTER>_FILTER_REGEX_EXCLUDE`,
`<LINTER>_ARGUMENTS`.

### Linters

| linter | files | tool |
|---|---|---|
| `PYTHON_RUFF`, `PYTHON_RUFF_FORMAT` | `.py` | ruff |
| `PYTHON_PYRIGHT` | `.py` | pyright in the repository's environment (`.venv`, or `PYTHON_PYRIGHT_PYTHON`) |
| `J2LINT` | `.j2`, `.jinja`, `.jinja2` | j2lint |
| `RST_DOC8`, `SPELL_VALE`, `SPELL_CODESPELL` | `.rst` | doc8, vale, codespell |
| `TYPESCRIPT_ESLINT` | `.ts`, `.tsx` | the repository's `node_modules/.bin/eslint` |
| `CPP_CLANG_TIDY` | C++ | clang-tidy on the repository's `compile_commands.json`; results are kept per file until it, a header it includes or a `.clang-tidy` above it changes (`~/.cache/peachycheck/results`, restored and saved by the CI action) |
| `CPP_CLANG_FORMAT` | C++ | clang-format with the nearest `.clang-format` (else LLVM's style) |
| `REPOSITORY_GITLEAKS` | every file | gitleaks |

### Generated files and compile commands

`GENERATED` names a JSON manifest whose entries list generated files, which
`lint` never checks (and `init` pins no dev dependency into a generated
`pyproject.toml`):

```yaml
GENERATED: {file: manifest.json, list: sources, path: path, where: {ownership: generated}}

clang-tidy needs the build's compile_commands.json: the first of build/peachycheck/compile_commands.json and build/compile_commands.json, or the path(s) CPP_CLANG_TIDY_COMPILE_COMMANDS names. Configure CMake with CMAKE_EXPORT_COMPILE_COMMANDS=ON (in CI through the action's prepare); without the file, each C++ file reports that as a problem.

Hooks

peachycheck hooks install adds two hooks to ~/.claude/settings.json and ~/.codex/hooks.json and prints the diff (trust Codex's once with /hooks):

• after each edit (Edit|Write|MultiEdit, Codex's apply_patch), peachycheck hook post-edit fixes and lints the edited files and feeds the findings back to the agent, with every linter but the slow ones (stage: stop, by default clang-tidy);
• before the agent stops, peachycheck hook stop lints the files changed since the merge base with all linters (no builds or tests); it blocks the stop on a failure, at most twice in a row, then lets the agent stop and shows what remains.

Each edited file counts for its own repository (the nearest folder above it with a peachycheck.yml), so a Codex patch that spans repositories is judged file by file. The Stop hook checks every repository with changes at or below the session's folder (its own, and side-by-side worktrees under a parent folder, three levels deep), each with its own lint. Files of no such repository are left alone, so one install serves the whole user. A repository whose .venv has another version of peachycheck (its dev pin) answers with that version. PEACHYCHECK_HOOKS=off turns them off; peachycheck hooks uninstall [--claude] [--codex] removes exactly these entries.

Claude Code plugin

Instead of peachycheck hooks install, Claude Code can take the same two hooks from this repository as a plugin (or add the marketplace drexlerd/peachycheck under a cloud project's settings):

/plugin install peachycheck --marketplace drexlerd/peachycheck

The plugin runs peachycheck hook post-edit after each Edit|Write|MultiEdit and peachycheck hook stop before Claude stops, with the peachycheck on PATH (install it as above). Without one, each hook prints a one-line notice and exits 0. Use either the plugin or peachycheck hooks install, not both, or each hook runs twice.

Findings

Each file's findings come with a link to the documentation of each rule:

a.py has 1 findings; fix each one:
  a.py:17: PYTHON_RUFF:N802 Function name `mixedCase` should be lowercase → https://docs.astral.sh/ruff/rules/invalid-function-name

A tool such as an agent loop can use peachycheck as a library: linting.lint_errors(root, base) returns these messages for the files changed since base.

Develop

uv sync
uv run pytest
uv run ruff check . && uv run ruff format --check . && uv run pyright
uv run peachycheck lint --all

The tests use the sample organization in tests/fixtures/org.

Release

Set version in pyproject.toml, merge, then tag the merge commit:

git tag v0.1.0 && git push origin v0.1.0

Before tagging, point .github/workflows/check.yml at the action of the new release (uses: drexlerd/peachycheck@v<version>). .github/workflows/release.yml checks that the tag matches the version and that check.yml uses its action, runs the checks, builds with uv build, publishes to PyPI by trusted publishing (environment pypi) and creates the GitHub release with the distributions.

Once, before the first release, add a pending publisher on PyPI (Account settings, Publishing, "Add a new pending publisher", GitHub): project peachycheck, owner drexlerd, repository peachycheck, workflow release.yml, environment pypi; and create the environment pypi in this repository's settings (Environments).

License

peachycheck is licensed under the GNU Affero General Public License v3.0 only (AGPL-3.0-only, see LICENSE).