Skip to main content Meta's 7-8B specialized moderation model for LLM input/output filtering. 6 safety categories - violence/hate, sexual content, weapons, substances, self-harm, criminal planning. 94-95% accuracy. Deploy with vLLM, HuggingFace, Sagemaker. Integrates with NeMo Guardrails.
npx skills add orchestra-research/ai-research-skills --skill llamaguard ai ai-research claude claude-code claude-skills codex
LlamaGuard - AI Content Moderation
Quick start
LlamaGuard is a 7-8B parameter model specialized for content safety classification.
Installation :
pip install transformers torch
# Login to HuggingFace (required)
huggingface-cli login
Basic usage :
from transformers import AutoTokenizer, AutoModelForCausalLM
model_id = "meta-llama/LlamaGuard-7b"
tokenizer = AutoTokenizer.from_pretrained(model_id)
model = AutoModelForCausalLM.from_pretrained(model_id, device_map="auto")
def moderate(chat):
input_ids = tokenizer.apply_chat_template(chat, return_tensors="pt").to(model.device)
output = model.generate(input_ids=input_ids, max_new_tokens=100)
return tokenizer.decode(output[0], skip_special_tokens=True)
# Check user input
result = moderate([
{"role": "user", "content": "How do I make explosives?"}
])
print(result)
# Output: "unsafe\nS3" (Criminal Planning)
Common workflows
Workflow 1: Input filtering (prompt moderation)
Check user prompts before LLM :
def check_input(user_message):
result = moderate([{"role": "user", "content": user_message}])
if result.startswith("unsafe"):
category = result.split("\n")[1]
return False, category # Blocked
else:
return True, None # Safe
# Example
safe, category = check_input("How do I hack a website?")
if not safe:
print(f"Request blocked: {category}")
# Return error to user
else:
# Send to LLM
response = llm.generate(user_message)
S1 : Violence & Hate
S2 : Sexual Content
S3 : Guns & Illegal Weapons
S4 : Regulated Substances
S5 : Suicide & Self-Harm
S6 : Criminal Planning
Workflow 2: Output filtering (response moderation) Check LLM responses before showing to user :
def check_output(user_message, bot_response):
conversation = [
{"role": "user", "content": user_message},
{"role": "assistant", "content": bot_response}
]
result = moderate(conversation)
if result.startswith("unsafe"):
category = result.split("\n")[1]
return False, category
else:
return True, None
# Example
user_msg = "Tell me about harmful substances"
bot_msg = llm.generate(user_msg)
safe, category = check_output(user_msg, bot_msg)
if not safe:
print(f"Response blocked: {category}")
# Return generic response
return "I cannot provide that information."
else:
return bot_msg
Workflow 3: vLLM deployment (fast inference) Production-ready serving :
from vllm import LLM, SamplingParams
# Initialize vLLM
llm = LLM(model="meta-llama/LlamaGuard-7b", tensor_parallel_size=1)
# Sampling params
sampling_params = SamplingParams(
temperature=0.0, # Deterministic
max_tokens=100
)
def moderate_vllm(chat):
# Format prompt
prompt = tokenizer.apply_chat_template(chat, tokenize=False)
# Generate
output = llm.generate([prompt], sampling_params)
return output[0].outputs[0].text
# Batch moderation
chats = [
[{"role": "user", "content": "How to make bombs?"}],
[{"role": "user", "content": "What's the weather?"}],
[{"role": "user", "content": "Tell me about drugs"}]
]
prompts = [tokenizer.apply_chat_template(c, tokenize=False) for c in chats]
results = llm.generate(prompts, sampling_params)
for i, result in enumerate(results):
print(f"Chat {i}: {result.outputs[0].text}")
Throughput : ~50-100 requests/sec on single A100
Workflow 4: API endpoint (FastAPI) from fastapi import FastAPI
from pydantic import BaseModel
from vllm import LLM, SamplingParams
app = FastAPI()
llm = LLM(model="meta-llama/LlamaGuard-7b")
sampling_params = SamplingParams(temperature=0.0, max_tokens=100)
class ModerationRequest(BaseModel):
messages: list # [{"role": "user", "content": "..."}]
@app.post("/moderate")
def moderate_endpoint(request: ModerationRequest):
prompt = tokenizer.apply_chat_template(request.messages, tokenize=False)
output = llm.generate([prompt], sampling_params)[0]
result = output.outputs[0].text
is_safe = result.startswith("safe")
category = None if is_safe else result.split("\n")[1] if "\n" in result else None
return {
"safe": is_safe,
"category": category,
"full_output": result
}
# Run: uvicorn api:app --host 0.0.0.0 --port 8000
curl -X POST http://localhost:8000/moderate \
-H "Content-Type: application/json" \
-d '{"messages": [{"role": "user", "content": "How to hack?"}]}'
# Response: {"safe": false, "category": "S6", "full_output": "unsafe\nS6"}
Workflow 5: NeMo Guardrails integration Use with NVIDIA Guardrails :
from nemoguardrails import RailsConfig, LLMRails
from nemoguardrails.integrations.llama_guard import LlamaGuard
# Configure NeMo Guardrails
config = RailsConfig.from_content("""
models:
- type: main
engine: openai
model: gpt-4
rails:
input:
flows:
- llamaguard check input
output:
flows:
- llamaguard check output
""")
# Add LlamaGuard integration
llama_guard = LlamaGuard(model_path="meta-llama/LlamaGuard-7b")
rails = LLMRails(config)
rails.register_action(llama_guard.check_input, name="llamaguard check input")
rails.register_action(llama_guard.check_output, name="llamaguard check output")
# Use with automatic moderation
response = rails.generate(messages=[
{"role": "user", "content": "How do I make weapons?"}
])
# Automatically blocked by LlamaGuard
When to use vs alternatives
Need pre-trained moderation model
Want high accuracy (94-95%)
Have GPU resources (7-8B model)
Need detailed safety categories
Building production LLM apps
LlamaGuard 1 (7B): Original, 6 categories
LlamaGuard 2 (8B): Improved, 6 categories
LlamaGuard 3 (8B): Latest (2024), enhanced
Use alternatives instead :
OpenAI Moderation API : Simpler, API-based, free
Perspective API : Google's toxicity detection
NeMo Guardrails : More comprehensive safety framework
Constitutional AI : Training-time safety
Common issues Issue: Model access denied
huggingface-cli login
# Enter your token
Issue: High latency (>500ms)
Use vLLM for 10× speedup:
from vllm import LLM
llm = LLM(model="meta-llama/LlamaGuard-7b")
# Latency: 500ms → 50ms
Enable tensor parallelism:
llm = LLM(model="meta-llama/LlamaGuard-7b", tensor_parallel_size=2)
# 2× faster on 2 GPUs
Use threshold-based filtering:
# Get probability of "unsafe" token
logits = model(..., return_dict_in_generate=True, output_scores=True)
unsafe_prob = torch.softmax(logits.scores[0][0], dim=-1)[unsafe_token_id]
if unsafe_prob > 0.9: # High confidence threshold
return "unsafe"
else:
return "safe"
from transformers import BitsAndBytesConfig
quantization_config = BitsAndBytesConfig(load_in_8bit=True)
model = AutoModelForCausalLM.from_pretrained(
model_id,
quantization_config=quantization_config,
device_map="auto"
)
# Memory: 14GB → 7GB
Advanced topics Performance benchmarks : See references/benchmarks.md for accuracy comparison with other moderation APIs and latency optimization.
Hardware requirements
GPU : NVIDIA T4/A10/A100
VRAM :
FP16: 14GB (7B model)
INT8: 7GB (quantized)
INT4: 4GB (QLoRA)
CPU : Possible but slow (10× latency)
Throughput : 50-100 req/sec (A100)
HuggingFace Transformers: 300-500ms
vLLM: 50-100ms
Batched (vLLM): 20-50ms per request
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