checkleft

Status: experimental / under active development. Not yet recommended for general use. The CLI behavior, built-in checks, and library API may change without notice.

checkleft is a repository convention checker. It runs built-in and external checks against the files in a source tree and reports findings as human-readable output or JSON.

Install

cargo install checkleft

Usage

Run from the root of a Git or Jujutsu repository:

checkleft run
checkleft run --verbose
checkleft run --all
checkleft run --external-checks-url https://example.com/CHECKS.yaml
checkleft list

checkleft looks for CHECKS.yaml or CHECKS.toml files from the repository root down to the file being evaluated.

The root config can also set settings.external_checks_url to merge an externally hosted root config before applying local root and child overrides. The CLI flag --external-checks-url provides the same behavior for repos that do not yet have a root config file.

Minimal config

checks:
  - id: typo
    check: typo

Notes

• checkleft shells out to git or jj to discover repository state.
• Some built-in checks are specific to Bazel- or monorepo-style workflows.
• JS/TS external checks in source mode cache built wasm artifacts under a repo-scoped path in ${XDG_CACHE_HOME:-$HOME/.cache}/checkleft/, and share the JS toolchain install across repos when the pinned toolchain inputs match. Those entries are derived-only and can be deleted to force a rebuild.