GitHub Actions

The linter auto-detects GitHub Actions via the GITHUB_ACTIONS environment variable and emits inline PR annotations by default — no extra flag required.

Lint + Format check

.github/workflows/herb.yml

name: Herb

on:
  push:
    branches: [main]
  pull_request:

jobs:
  herb:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - uses: actions/setup-node@v4
        with:
          node-version: 20
      - name: Lint HTML+ERB templates
        run: npx --yes @herb-tools/linter

      - name: Check HTML+ERB formatting
        run: npx --yes @herb-tools/formatter --check

The formatter requires an explicit path in CI — without one it reads from stdin, which --check rejects. Adjust app/views to match where your templates live.

Formatter is in experimental preview

@herb-tools/formatter prints an experimental-preview banner on every invocation, and --check will fail on any codebase that hasn't already been run through herb-format. Before wiring this step into CI, see Adopting the formatter below.

Adopting the formatter

--check only passes on an already-formatted tree. Run the formatter once, commit the result in its own change, then enable the CI step:

npx --yes @herb-tools/formatter

Review the diff, commit it separately from unrelated changes, and only then add the --check step to your workflow.

Stricter lint gate

Fail the build on warnings in addition to errors:

- name: Lint HTML+ERB templates
  run: npx --yes @herb-tools/linter --fail-level warning

Quieter lint annotations

Large codebases can produce a lot of info and hint offenses, which show up as notice annotations on the pull request. Use --log-level to keep the annotations focused:

- name: Lint HTML+ERB templates
  run: npx --yes @herb-tools/linter --log-level warning

Offenses below the level are still counted in the summary and still respected by --fail-level, they just don't get annotated.

To apply the same level to local runs as well, set it in .herb.yml instead of passing the flag:

.herb.yml

linter:
  logLevel: warning

The CLI flag takes precedence, so you can keep the config as the default and still pass --log-level hint in a workflow that should see everything.

Parser analysis (Ruby)

herb analyze reports how many templates parse cleanly and exits non-zero when any issue is detected (see lib/herb/cli.rb), so it can gate the build on its own.

Append these steps to the herb job above to also run the parser analyzer, or put them in a separate job if you prefer to parallelize:

- uses: ruby/setup-ruby@v1
  with:
    bundler-cache: true

- name: Analyze HTML+ERB templates
  run: bundle exec herb analyze .