The reusable capability format and its ecosystem: the open spec, the vendor implementations, the harness mechanisms, the optimizer, and the registries and curated packs.
- Agent Skills open standard - the agentskills.io spec for SKILL.md capability directories.
- Agent-Native - Builder.io’s curated pack of fifteen skills plus the app framework they bridge to, the discipline skills portable to any harness.
- Anthropic Agent Skills - Anthropic’s SKILL.md folder format for reusable agent capabilities.
- OpenCode skills and plugins - OpenCode’s two extension mechanisms: skills for the model, plugins for the harness.
- SkillOpt - Microsoft Research’s optimizer that trains skill markdown against held-out validation, skills as trainable parameters.
- skills.sh - Vercel’s directory and leaderboard for the open skills ecosystem.
Its members are compared on shared rows in the Skills Feature Matrix.
Changes #
- 2026-08-24 - Added Agent Skills open standard.
- 2026-08-24 - Added Anthropic Agent Skills.
- 2026-08-24 - Added OpenCode skills and plugins.
- 2026-08-24 - Added skills.sh.
- 2026-08-30 - Added SkillOpt.
- 2026-09-13 - Added Agent-Native.