Custos — The bouncer for your AI agents

Custos is a safety and control layer for AI agents. It sits between an agent and the tools it uses—like APIs, files, databases, shell commands, and MCP servers—and checks every action before it runs. You define what the agent is allowed to do, Custos blocks anything outside those rules, and every action is recorded in a tamper-evident audit trail. It’s open source, works with Python and TypeScript, and is built for teams running AI agents in real-world environments.