Where Semgrep wins
If your team needs a fully customizable static analysis engine — writing your own rules for your own codebase’s specific risks — Semgrep is the right tool. It’s flexible, fast, and has a large community rule registry.
Where Prbl is different
Prbl trades flexibility for zero setup and a sharp focus. There’s no rule registry to browse and no custom Semgrep syntax to learn — the rules are already tuned to the specific vulnerability classes AI coding tools produce systematically: hardcoded credentials, injection from string concatenation, missing auth on generated routes, and fallback secrets.
Run both
Many teams already run Semgrep for general SAST coverage and add Prbl specifically for the AI-generated portion of their codebase, since that’s the part most existing rule sets weren’t written with in mind.