Skills Lint Validation

Validating Skills with skills_lint

This skill covers day-to-day use: running the linter, walking through a failing run, and writing a custom rule when defaults aren't enough. For first-time wiring (adding the dep, creating the config file, generating a baseline) see skills-lint-setup. The full rule reference (default severities, diagnostic shapes, fixability) lives in RULES.md.

Running the linter

If skills_lint is in pubspec.yaml:

dart run skills_lint -d .agents/skills

If it's installed globally with dart install:

skills_lint -d .agents/skills

Run dart run skills_lint --help (or skills_lint --help) for the full flag list (skip the inline duplicate so it never goes stale).

Workflow for a failing run

1. Run the validator.
2. Read the errors. Each diagnostic names the rule that fired, the offending value, and a suggested fix when one applies.
3. Fix the violations. For fixable rules (check-absolute-paths, check-trailing-whitespace, invalid-skill-name), pass --fix to write the corrections to disk; add --dry-run to preview the diff first.
4. Re-run to confirm the run is clean.

Task progress

• Run validator
• Read errors
• Fix violations (manual or --fix / --fix --dry-run)
• Verify clean run

Authoring a custom rule

Extend SkillRule and pass the rule into validateSkills:

import 'package:skills_lint/skills_lint.dart';

class DeprecatedSkillRule extends SkillRule {
  @override
  final String name = 'deprecated-skill';

  @override
  final AnalysisSeverity severity = AnalysisSeverity.warning;

  @override
  Future<List<ValidationError>> validate(SkillContext context) async {
    final errors = <ValidationError>[];
    final yaml = context.parsedYaml;
    if (yaml == null) return errors;

    if (yaml['metadata']?['deprecated'] == true) {
      errors.add(ValidationError(
        ruleId: name,
        severity: severity,
        file: 'SKILL.md',
        message: 'This skill is marked as deprecated.',
      ));
    }
    return errors;
  }
}

Wire it up in a Dart test:

import 'package:skills_lint/skills_lint.dart';
import 'package:test/test.dart';

void main() {
  test('skills pass with deprecated-skill custom rule', () async {
    final config = await ConfigParser.loadConfig();
    expect(
      config.directoryConfigs,
      isNotEmpty,
      reason: 'Configuration directoryConfigs should not be empty.',
    );
    await validateSkills(
      config: config,
      customRules: [DeprecatedSkillRule()],
    );
  });
}

Related

• skills-lint-setup — first-time wiring.
• RULES.md — canonical rule reference.
• README.md — installation, configuration, integration recipes.