The reusable capability format and its ecosystem: the open skill format spec, the vendor-neutral packaging envelope over it, the vendor implementations, the harness mechanisms, the optimizers, the security scanner, the registries and curated packs, and the hosted-execution marketplace.
- Agent Plugins - the vendor-neutral packaging standard bundling Agent Skills and MCP servers into one portable plugin.json folder, from a Vercel-proposed five-vendor TSC.
- Agent Skills open standard - the agentskills.io spec for SKILL.md capability directories.
- Agent-Native - Builder.io’s curated pack of 24 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.
- EvoSkill - Sentient Labs’ Apache-2.0 toolkit that induces SKILL.md skills from a coding agent’s failed benchmark runs, keeping only held-out improvements on a git-branch Pareto frontier, quiet since August.
- GEPA - the MIT reflective prompt optimizer from the Databricks research lineage that mechanically evolves prompts, code, and agent skills against any metric, about 7k stars.
- Headcount - Chris Brock’s 16-department plugin marketplace for Claude Code and ChatGPT, skills owned by write surface and reviewer-class departments that can block.
- OpenCode skills and plugins - OpenCode’s two extension mechanisms: skills for the model, plugins for the harness.
- Sepia - Nanako0129’s research-grounded de-AI writing skill, repairing narrative structure instead of word choice, portable across 77+ agents.
- SkillMD - the verification-first open registry, publishing lint and scanner verdicts per skill, 1,948 of its about 1.13M listed skills safety-reviewed.
- SkillOpt - Microsoft Research’s optimizer that trains skill markdown against held-out validation, skills as trainable parameters.
- skills.md - Hasna’s hosted-execution marketplace, skills that run server-side with quoted per-run credits and a $10-per-month Pro plan.
- skills.sh - Vercel’s directory and leaderboard for the open skills ecosystem.
- SkillSpector - NVIDIA’s Apache-2.0 scanner for agent skills, 71 patterns plus an optional LLM pass scoring each skill SAFE, CAUTION, or DO NOT INSTALL before you install it.
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.
- 2026-09-27 - Added Headcount.
- 2026-09-27 - Added Sepia.
- 2026-10-05 - Added SkillMD.
- 2026-10-06 - Added Agent Plugins.
- 2026-10-06 - Added skills.md.
- 2026-10-12 - Added SkillSpector.
- 2026-10-13 - Added GEPA.
- 2026-10-13 - Added EvoSkill.