ToolsMay 4, 2026via Vercel Blog
Introducing deepsec: The security harness for finding vulnerabilities in your codebase
Why it matters
Vercel shipped a production-ready coding agent product (deepsec) that automates vulnerability detection across large codebases using Claude Opus and GPT-5.5. This is a concrete application of AI agents solving enterprise security workflows at scale, with real deployment data from Vercel's own monorepos.
Key signals
- deepsec open-sourced as security harness powered by coding agents
- Runs on local infrastructure; supports Claude Opus 4.7 and GPT-5.5 for inference
- Scales to 1,000+ concurrent sandboxes via Vercel Sandboxes for parallel execution
- 10-20% false positive rate; includes revalidation step to reduce noise
- Tested on Dub.co (open source) and Vercel's own monorepos; identified subtle auth edge cases
- Ships with plugin system for custom scanners (regex matchers, auth model tuning)
- Works with both standard and 'cyber' versions of Claude/OpenAI models
- Multi-step workflow: Scan → Investigate → Revalidate → Enrich → Export
The hook
Not a pilot. Vercel just open-sourced an AI security agent that scales to 1,000+ concurrent scans—and it catches what static analysis misses.
Today we’re open sourcing : a security harness powered by coding agents. It runs on your own infrastructure and surfaces hard-to-find issues in large codebases. deepsec
You can run on your laptop without setting up a cloud service for privileged source code access. For inference, you can use your e…