Add Static analysis tool written in dart that checks for skill compliance with the open skills specification.

[reidbaker]

Design doc (googler only) go/flutter-dart-skills-lint-publish-plan
Fixes: #59

Review overview:

• .agent/skills/
• • add-dart-lint-validation-rule is a custom skill for working on the linter.
• • The rest were installed with npx. I could use a second opinion about what should be checked in from hosted skills.
• feature_design_docs/ are ai artifacts of unimplemented features. I don't think the contents need review but I am open to opinions about if this kind of thing is something we are ok with checking in.
• knowledge/ is for docs about the structure of the lint codebase. Also ai artifacts. You are welcome to review contents but it is a lower priority.
• lib/src/models
• • These are "just" simple dart models but that means the bar for quality is high. Would appreciate review on on both the structure and documentation/understandability of all of the model objects.
• lib/src
• • This is the bulk of the actual code
• • Would appreciate review on patterns that are bad/wrong and for structural feedback (e.g better method organization)
• tests
• • Most important: Missing classes of tests or areas you think that are easy to regress
• • Patterns that are bad across all the test.
• README.md
• • Any documentation you see that is incorrect
• • Questions you would have as a consumer that are not answered.

Finally any advice you have to make this code more maintainable moving forward. How to integrate it into your cicd etc. I think ci changes should go into a second pr but it may still be valuable to talk about it here.

Features that need to be added.
Ignores for -d so that .dart_tool and other directories can be ignored.

Pre-launch Checklist

• I read the [Contributor Guide] and followed the process outlined there for submitting PRs.
• I read the [Tree Hygiene] wiki page, which explains my responsibilities.
• I read the [Flutter Style Guide] recently, and have followed its advice.
• I signed the [CLA].
• I listed at least one issue that this PR fixes in the description above.
• I updated/added relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or this PR is [test-exempt].
• All existing and new tests are passing.

[reidbaker]

/gemini review

[reidbaker]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces a static analysis linter for Agent Skills, including the core validation engine, CLI entry point, and configuration parsing logic. The review feedback highlights concerns regarding the mutation of global state within the CheckType objects during configuration parsing and rule resolution, suggesting a shift toward immutable configuration objects. Additionally, there is a recommendation to improve the robustness of the YAML frontmatter parsing by moving away from reliance on a single global regular expression.

[gemini-code-assist]

Using a single global regex for parsing YAML frontmatter might fail if the file content is large or if the frontmatter format varies slightly. Consider using a more robust YAML parser that can handle the full file content or a dedicated frontmatter parsing library.

[reidbaker]

Confirmed in chat that johnpryan says not to wait for the second review.