Lint

The wmill lint command validates Windmill YAML files (flows, schedules, and triggers) against their schemas. It scans a directory tree, infers each file's type from its filename (.flow.yaml, .schedule.yaml, .http_trigger.yaml, etc.), and reports missing required fields, unknown properties, or invalid values.

Usage

wmill lint [directory] [options]

If no directory is provided, the current directory is used. The command respects the includes/excludes patterns from your wmill.yaml.

Options

Option	Description
--json	Output machine-readable JSON instead of formatted text.
--fail-on-warn	Exit non-zero on warnings (e.g. skipped native triggers).
--locks-required	Fail if any script or inline script that needs a lock is missing one.

Native triggers (triggers whose schema depends on a dynamic service_config) are skipped with a warning — no static schema is available for them.

Examples

Lint every YAML file under the current directory:

wmill lint

Lint a specific folder and emit JSON for CI tooling:

wmill lint f/my_project --json

Fail the build if any script/flow/app inline script is missing its lockfile:

wmill lint --locks-required

--locks-required

--locks-required checks standalone scripts, flow inline scripts, normal app inline scripts, and raw app backend scripts. It applies to languages that need a lock: bun, python3, php, go, deno, rust, and ansible.

The flag can also be enabled globally in wmill.yaml:

locksRequired: true

When set, wmill sync push runs the same verification before pushing, failing fast if anything is missing.

CI integration

A typical GitHub Actions step:

- name: Validate Windmill YAML files
  run: |
    npm install -g windmill-cli
    wmill lint --fail-on-warn --locks-required

Pair wmill lint with wmill generate-metadata to (re)generate any missing lockfiles before linting.