This is your structured approach to writing specs that won't get you lost three sprints in. It gives you a markdown template covering requirements, architecture, API design, database schemas, and testing strategy. Everything is organized into tables with priority levels and risk assessments. The template includes non-functional requirements with actual numbers (99.9% uptime, 200ms response time) instead of hand-wavy "should be fast" statements. Use it when you need to document a feature properly before building it, or when you're tired of specs that skip over the hard questions like rollback plans and security considerations. It's opinionated about what goes where, which is the point.
npx skills add https://github.com/secondsky/claude-skills --skill technical-specification