Show HN: Governor, a firewall for AI agent spend and tool calls

A developer released Governor, a Node 18+ dependency-free proxy that sits between AI agents and Anthropic, OpenAI or xAI APIs to enforce per-agent spending caps and tool-call rules, with every decision signed into an audit log. Governor inspects tool calls inside each model reply before the agent receives them, blocking calls a rule denies and holding calls a rule flags for human approval, with rules checked in order and unmatched calls passing through. Setup requires changing the SDK base URL and issuing each agent its own Governor key with its own caps and tool rules.

Watch Governor stop an AI agent Each button makes a scripted agent call an AI model through Governor. The model here is fake no real AI, no cost , but every call goes through the real Governor, and every decision is signed into its audit log. No sign-up. 1. Make the agent act Loading... The rules on this agent's key ... Checked in order; the first rule that matches a tool call decides it. Calls no rule matches pass. 2. What Governor decided Press a button on the left. Results show here, newest first. How this works in your own setup 1. Governor runs as a small proxy Node 18+, no dependencies between your agents and Anthropic, OpenAI or xAI. 2. You change the base URL in your SDK and give each agent its own Governor key with its own caps and tool rules. 3. Governor sees the tool calls inside each model reply before your agent does. It blocks the ones a rule denies and holds the ones a rule says need a person.