Two Requests That Look Similar But Need Different Mechanisms

A technical-writing team working in a docs-only repository makes two requests:

• Request A: "Every response Claude gives in this repo — no matter what we ask — should be bullet points only, no prose paragraphs, and should never suggest code changes since this repo has no code."
• Request B: "When someone asks Claude to draft a new API reference page, it should pull the OpenAPI spec, follow our house style for parameter tables, and flag anything undocumented — but only when someone actually asks for a new page, not on every message."

1. Which mechanism fits Request A, and specifically why would a skill with a very broad description be the wrong tool even if you tried hard to make it auto-trigger on everything?
2. Which mechanism fits Request B, and what frontmatter field keeps it from firing outside of an explicit ask?
3. A team member proposes solving both with one skill that has no disable-model-invocation and an extremely generic description like "helps with anything in this repo." Explain concretely what would go wrong.