Show HN: Fence – Jiminy Cricket for AI coding agents

Hi everyone, I'm Andrios, founder of hoop.dev (YC W21).

2 weeks ago, I told our eng team they could spend 20% of their week on side projects. The result: They came out with 3 open source projects. Tools we're using ourselves.

Fence is the first one. It prevents an agent, confused or poorly prompted, to execute a catastrophic command before it happens. This could be 'rm -rf~’, ‘rm -fr~’ or even ‘sudo rm -rf $HOME’. It’s different from a denylist, because it reads the intention, not only the string.

We use this for Claude Code and Codex. We want to see adoption before jumping to Cursor next.

The team is very excited to release this, so please to drop any comments with feedback or issues you find:

github.com/hoophq/fence