Cleo solves the "works on my machine" problem for Claude Code setups. You define a manifest once — listing rules, skills, agents, commands, hooks, and MCP configurations stored in any git repository — and cleo install gives every team member the identical environment. cleo update pulls the latest versions; cleo.lock pins exact commit SHAs so installs are reproducible and auditable. There's no central registry or account required: packages resolve directly from GitHub using a simple vendor/name format. Every install runs validation on paths, refs, manifest shape, and hook sizes before anything is written. Cleo installs as either a Claude Code plugin or a standalone CLI via pip.