What is an Agent Skill?
An agent skill is a folder with a SKILL.md file: YAML frontmatter with a name and a description, then instructions and commands. The agent reads only the description until a task calls for the skill, then loads the rest.
Claude Code reads skills from ~/.claude/skills. Cursor, OpenAI Codex, Devin Desktop (Windsurf), VS Code Copilot and Gemini CLI all document reading ~/.agents/skills, so one file in that folder works across them.
How qURL Fits
The qURL skill at layerv.ai/skills/qurl/SKILL.md teaches an agent to install the qurl CLI, publish a local app privately, give you an address to send, and apply your private access rules, and send invitation emails only to recipients you authorize. Email verification codes stay in each recipient’s browser flow.