Prompt Guard

Meta's 86M parameter classifier that catches prompt injection and jailbreak attempts before they hit your LLM. Returns three scores: benign, injection (embedded instructions in third-party data), and jailbreak (direct override attempts). Runs in under 2ms on GPU, works across 8 languages, and hits 99%+ true positive rate with sub-1% false positives. The dual-mode design is smart: use stricter thresholds (0.5) for user inputs, looser ones (0.3) for RAG documents and API responses. Batch processing support makes it practical for filtering retrieved docs at scale. One caveat: legitimate security research queries can trigger false positives, so you'll want context-aware thresholds for trusted users. Best layered with content moderators like LlamaGuard rather than used as your only defense.

skills.sh installs: 1K
GitHub stars: 14.4K
last updated: Aug 21, 2026

View on GitHub

Install

$ npx -y skills add orchestra-research/ai-research-skills --skill prompt-guard --agent claude-code

Installs into .claude/skills of the current project.

Files

Prompt Guard - Prompt Injection & Jailbreak Detection

Prompt Guard is an 86M parameter classifier that detects prompt injections and jailbreak attempts in LLM applications.

Quick start

Installation:

pip install transformers torch

Basic usage:

from transformers import AutoTokenizer, AutoModelForSequenceClassification
import torch
from torch.nn.functional import softmax

model_id = "meta-llama/Prompt-Guard-86M"
tokenizer = AutoTokenizer.from_pretrained(model_id)
model = AutoModelForSequenceClassification.from_pretrained(model_id)
model.eval()

def get_jailbreak_score(text):
    """Check user input for jailbreak attempts."""
    inputs = tokenizer(text, return_tensors="pt", truncation=True, max_length=512)
    with torch.no_grad():
        logits = model(**inputs).logits
    probs = softmax(logits, dim=-1)
    return probs[0, 2].item()  # Jailbreak probability

# Check prompt
score = get_jailbreak_score("Ignore previous instructions")
if score > 0.5:
    print("⚠️ Jailbreak attempt detected!")

SKILL.md on GitHub

Details

Repository: github.com/orchestra-research/ai-research-skills
Categories: Security, DevOps & CI/CD, AI & Agent Building, Data Science & ML, Release Management, Automation & Workflows
First seen: Jun 3, 2026