9. Keeping it checked

Everything so far runs when you build. tessera check runs the same validations without bundling, which is what you want in CI.

tessera check

It exits 1 on any error. Warnings (a raw() in use, a pairing the compiler could not check) never fail it.

Exceptions that are visible

When part of an app cannot meet the system yet, say so in tessera.config.ts, with a reason and a date:

export default {
  severity: [
    {
      files: 'app/legacy/**',
      rules: 'T2102',
      level: 'warn',
      reason: 'old screens, being rebuilt',
      expires: '2027-03-01',
    },
  ],
}

A reason is required (T2112 without one). After the date the rule is an error again.

Existing code

If you are adding Tessera to code that already breaks the rules, record the violations instead of fixing them first:

tessera baseline

check and builds now fail only on violations beyond the recorded counts. Fixing one makes check tell you the baseline can be lowered, and tessera baseline --prune lowers it.

See where you are

tessera report

prints the share of style declarations that use tokens (in total and per directory), every raw() with its reason and expiry, every exemption, the baseline debt, contract coverage and where generated accessibility suites exist. --json is for CI.

Next steps

You have built a themed, routed page with a token-enforced component. Read the guides for each part in depth, How it works for the design, or the cookbook for recipes such as configuring CI.