The skills CLI is a tool for managing reusable instruction sets (skills) for AI coding agents. It enables users to discover, install, update, and remove skills from various sources including GitHub, GitLab, local paths, and well-known endpoints. Skills are installed to agent-specific directories (e.g., for Claude Code, Cursor, GitHub Copilot) via symlinking or copying, with tracking via lock files to support updates and reproducibility. The application follows a modular command-based architecture, with each command (add, remove, list, etc.) implemented in separate files. Key reusable components include a provider pattern for extensible skill sources, a lock file system for tracking installed skills, a secure installer with path safety checks, and input sanitization to prevent terminal injection vulnerabilities. The tool also collects anonymous telemetry (with opt-out) to improve the ecosystem.