Promptfoo
mit-licensed, free for ten thousand probes a month, and the only free tool here that tests agent tool access.
the most capable thing here you can run today, and the only free option that understands your application rather than just your model.
mit-licensed with a genuinely usable free allowance — 10,000 red-team probes a month — covering more than 50 named vulnerability types: prompt injection, jailbreaking, rag document exfiltration, system-prompt override, malicious resource fetching, pii leakage, unauthorised data access and tool and function discovery.
that last one matters. promptfoo frames its testing as 'dynamic attacks tailored to your application' including agent tool discovery, which puts it at the application and agent layer rather than probing a bare model. garak, its closest free rival, tests a single model and cannot tell you anything about what an agent does with its tools.
the description above is ours, condensed from the ranking. pricing moves — check it on the vendor's own page before you rely on it.
- category
- ai red-teaming tools
- pricing
- free
- website
- promptfoo.dev
the most capable thing here you can run today, and the only free option that understands your application rather than just your model.
we researched this category against vendors' own pricing pages and licence files. that is where this line comes from — not from the vendor, and not from anything they paid for.
more ai red-teaming tools
Garak
we checked thisfreeapache 2.0 from nvidia, twenty-plus probe modules, and a peer-reviewed paper behind it.
Adversa AI
we checked thisnot publishedthe most itemised attack taxonomy and the only vendor naming five compliance frameworks — behind a demo form.