Agent Skills 0.5.0

Release Notes

New Skills

• Source-Driven Development (#45) - New skill that grounds framework-specific implementation decisions in official documentation. Covers stack detection, citation format, handling conflicting sources, and an optional documentation cache. Framework-agnostic by design.

Skill Improvements

Performance Optimization (#40)

• Distinguished synthetic (Lighthouse/CI) vs RUM (web-vitals) measurement, with guidance on when each applies.
• Expanded TTFB diagnosis into a decision tree covering DNS, TCP/TLS, and server processing — mirrored in the checklist with TTFB "good" threshold aligned to web.dev (800ms).
• Fixed image optimization examples: hero/LCP images now use aspect-ratio, fetchpriority="high", and explicit width/height; below-the-fold images use loading="lazy" + decoding="async". Removed decoding="sync" from hero examples to avoid blocking the main thread.
• Added art direction + resolution switching example with <picture>, AVIF → WebP → JPG cascade, and realistic sizes attributes.
• Corrected the date-fns tree-shaking example — modern bundlers handle named imports; replaced with dynamic imports and route-level code splitting.
• Added Suspense wrapper to code-splitting examples; clarified ESM + sideEffects: false requirements.

Spec & Task Lifecycle (#42)

• Clarified spec and task file lifecycle (fixes #39).

Documentation & Setup Guides

• Gemini CLI (#43): Improved configuration guide and fixed installation path for skills.
• GitHub Copilot: Corrected skills setup instructions (#21).
• OpenCode: Added integration with agent-driven skill execution; clarified command support and agent-driven design.
• Marketplace install (#37): Added SSH troubleshooting hint.

Cross-Reference Additions (#34)

Added "See Also" sections across multiple SKILL.md files linking to:

• Security checklist references
• Performance resources
• Accessibility resources
• Testing patterns
• Pre-launch checklists (security, performance, accessibility)
• Review guidance (security and performance review checklists)

Contributors

@federicobartoli, @nucliweb, @zerone0x, @bonigarcia, @faisalbasra, @dj2313, @cseas