Introducing deepsec: The security harness for finding vulnerabilities in your codebase

Vercel open-sourced deepsec, a security harness that uses coding agents (Claude and Codex) to find vulnerabilities in large codebases.

It runs on a user's own infrastructure, supports optional parallel execution via Vercel Sandboxes, and includes a plugin system for custom scanners.

The tool has been tested internally and on customer codebases, with a reported false positive rate of roughly 10-20%.