Shannon is an autonomous AI penetration tester for web applications and APIs, built by Keygraph and released as open source. Rather than just scanning and listing possible issues, Shannon analyzes your source code, maps attack paths, and executes real exploits to prove a vulnerability exists before it reaches production. The repository has gathered over 49,000 GitHub stars and was actively developed in October 2026.
Most security scanners produce long reports full of theoretical findings. Shannon follows a stricter rule: no exploit, no report. It reads your codebase, identifies where attacks could land, and then actually carries them out against a running instance of your app, so the findings that come back are verified, reproducible vulnerabilities rather than guesswork. It launches from the command line with a single npx command and fits into CI/CD pipelines, producing output in formats security teams already use, including SARIF.
The Shannon agent in this repository is free and open source to run locally. Keygraph, the company behind it, also offers commercial services around Shannon for teams that want a managed or supported deployment, so overall it follows a freemium model.
Shannon is aimed at developers, security engineers, and red teams who want continuous, evidence-based security testing without waiting for a manual pentest slot. It is especially useful for teams shipping web APIs quickly who need proof, not just alerts, before release.