skills/ is the canonical, agent-agnostic location for SKILL.md-format workflow guides.
Route to skills by the description field in each SKILL.md frontmatter, which states when that skill applies. Load only the skills the task needs; do not bulk-load the library.
Read skills/SKILLS.md when the task spans several skills, or when you need the composition order between them. It is a routing map, not a prerequisite for every conversation.
Cursor and Claude Code load the same skills via their respective pointer mechanisms (.cursor/rules/agent_skills.mdc, CLAUDE.md). For Codex (this file), the skills are background context — refer to them when the user's task overlaps a skill's subject.
.cursor/rules/ holds the *.mdc style and policy rules (C++ codestyle, Python codestyle, docs style, extension structure, build instructions, pip packaging, ...). Load them on demand when editing code that falls under their domain.
Skills are authored once under skills/. .claude/skills/ contains symlinks into skills/ so Claude Code's native skill discovery works without duplication. .cursor/skills/ is retired.