Knowledge and project-owned rules

Nice Code has two separate resource surfaces.

The package-owned knowledge base lives in the Nice Code repository under knowledge/, patterns/, skills/, and sources/. Its registry and review dates are maintainer concerns. Contributors run npm run knowledge:compile, npm run knowledge:check, npm run knowledge:outdated, and npm run check:contributor; ordinary projects do not need these commands.

Projects may attach their own guidance and safe deterministic checks without modifying Nice Code:

.nice-code/
  checks.json
  rules/team-java.md
  resources/architecture.md

.nice-code/checks.json is the explicit format. A Markdown rule file can declare the same checks in front matter, so teams can write prose guidance and checks together. IDs must begin with CUSTOM-, and matchers are literal by default or regex when matcherType is set. Checks are scoped by file extension and detected profile, and test files are skipped unless includeTests is true.

The equivalent JSON rule is:

{
  "checks": [
    {
      "id": "CUSTOM-ACME-001",
      "title": "Avoid legacy dates",
      "matcher": "java.util.Date",
      "extensions": ["java"],
      "appliesTo": ["java", "spring-boot"],
      "severity": "warning",
      "message": "Use java.time APIs instead."
    }
  ]
}

Project Markdown resources are advisory context only; they are never merged into Nice Code's trusted knowledge registry. Nice Code does not execute project shell commands as custom rules.

Developer rule authoring

Developers can use the bundled authoring helper instead of hand-writing JSON:

nice-code rules init --project .
nice-code rules validate --project .
nice-code rules compile --project . --apply

Only explicit checks in .nice-code/rules/*.md are compiled. Validation rejects malformed IDs, matchers, scopes, severities, and messages. Existing checks.json files are never silently overwritten.

Use nice-code --changed --project . locally and nice-code --changed --ci --format sarif --project . in CI. Pair it with the project's compiler, formatter, dependency analysis, and test commands.