Llama Guard
The strongest classifier here — but read the licence before you ship it.
Llama Guard is Meta's safety-classification model family, fine-tuned to classify prompts and responses against a configurable taxonomy — and unusually, the taxonomy is a parameter you can edit rather than a fixed list, so your categories can be your own. As a purpose-trained model it outperforms rule-based scanners on nuanced content. The caveat we will not bury: it ships under Meta's Llama Community License, not an OSI-approved open-source licence. It is free for most use but carries acceptable-use terms and a scale threshold, so it is not open source in the sense the rest of this list is.
What it does well
- +Best classification quality of the options here
- +Editable taxonomy — your safety categories, not a vendor's
- +Runs entirely on your own hardware
- +Classifies both prompts and responses
Where it falls short
- −Not open source — Llama Community Licence with acceptable-use terms
- −Licence carries a monthly-active-user threshold; check it applies to you
- −Needs GPU capacity alongside your main model
Llama Guard as an alternative to
Where Llama Guard shows up in our comparisons, and how it ranked.
Llama Guard head-to-head
Straight comparisons against the tools people weigh it against.