The verifier

cherry check builds the whole site in memory, writes nothing, and runs every rule against the result. It's the difference between "the build passed" and "the site is right."

A worked failure

Add a link to a page that doesn't exist, then check:

cherry check --strict --json

{
  "ok": false,
  "command": "check",
  "error": {
    "code": "check_failed",
    "message": "Checked 12 page(s): 1 error(s), 0 warning(s).",
    "details": {
      "errors": 1,
      "warnings": 0,
      "pages": 12,
      "diagnostics": [
        {
          "file": "content/pages/reading.md",
          "rule": "broken-link",
          "severity": "error",
          "message": "links to /guides/pruning/, which this build does not emit",
          "line": null
        }
      ]
    }
  }
}

Everything needed to fix it is in the diagnostic: the file, the rule, and a message naming the exact href. Exit code 1 tells CI; details.diagnostics tells whatever script is watching. Fix the link, run again:

{
  "ok": true,
  "command": "check",
  "data": {
    "errors": 0,
    "warnings": 0,
    "diagnostics": [],
    "pages": 12
  }
}

The rules

Rule	Catches	Severity
`broken-link`	internal hrefs the build doesn't emit, nav links included	error
`missing-description`	posts and pages without a `description:` (SEO contract)	warning
`missing-alt`	images without alt text	warning
`duplicate-title`	two pages claiming the same title	warning
`feed-missing` / `feed-invalid`	Atom or JSON Feed absent or malformed	error
`stale-overlay` / `untracked-overlay`	theme drift (see themes)	warning

--strict promotes warnings to errors; use it in CI so nothing rots quietly. This site runs check --strict on every commit.

Tip

check accepts --drafts and --future too, so you can verify work-in-progress exactly as serve shows it.

Where it fits

Run it after every meaningful edit, not just before deploys. It's fast, it writes nothing, and the loop is the point: build, check, fix, repeat until exit 0, then ship. The scripting guide shows the same loop driven entirely through envelopes.