BananaMind-Content-Safety-Mini-1.5

Note: This model is still experimental, do not use it in production!

BananaMind-Content-Safety-Mini-1.5 is a small text-only content-safety classifier based on LiquidAI/LFM2.5-350M-Base.

It classifies an input prompt as either Safe or Unsafe and, for unsafe content, returns violated safety categories.

This model is intended for lightweight prompt moderation, safety filtering, and local safety classification.

Model Details

Prompt format:

You are a strict content-safety classifier.

Classify the input as Safe or Unsafe.

Return exactly one of these formats:

Safe

or:

Unsafe
Violated Categories: <categories>
Input: {text_to_classify}

Target format for safe content:

Safe

Target format for unsafe content:

Unsafe
Violated Categories: <categories>

Evaluation

Evaluated on the text-only test split of nvidia/Nemotron-3.5-Content-Safety-Dataset.

Confusion matrix:

The model is optimized for high unsafe recall. It catches most unsafe prompts, but it can over-classify some safe prompts as unsafe.

Comparison

Usage

import torch
from transformers import AutoModelForCausalLM, AutoTokenizer

model_id = "BananaMind/BananaMind-Content-Safety-Mini-1.5"

tokenizer = AutoTokenizer.from_pretrained(model_id, use_fast=True)
model = AutoModelForCausalLM.from_pretrained(
    model_id,
    dtype=torch.bfloat16 if torch.cuda.is_available() and torch.cuda.is_bf16_supported() else torch.float16,
    device_map="auto",
)

text_to_classify = "How can I bypass a website login?"

prompt = f"""You are a strict content-safety classifier.

Classify the input as Safe or Unsafe.

Return exactly one of these formats:

Safe

or:

Unsafe
Violated Categories: <categories>
Input: {text_to_classify}
"""

inputs = tokenizer(prompt, return_tensors="pt").to(model.device)

with torch.no_grad():
    output = model.generate(
        **inputs,
        max_new_tokens=64,
        do_sample=False,
        pad_token_id=tokenizer.eos_token_id,
        eos_token_id=tokenizer.eos_token_id,
    )

prediction = tokenizer.decode(
    output[0][inputs["input_ids"].shape[-1]:],
    skip_special_tokens=True,
).strip()

print(prediction)

Example unsafe output:

Unsafe
Violated Categories: Cyber

Safe example:

text_to_classify = "How do I bake banana bread?"

Expected output:

Safe

Training Data

This model was trained on text-only rows from nvidia/Nemotron-3.5-Content-Safety-Dataset.

License

This model is based on LiquidAI/LFM2.5-350M-Base, which uses the LFM Open License v1.0.

The training dataset is nvidia/Nemotron-3.5-Content-Safety-Dataset. See THIRD_PARTY_LICENSES.md for more info.

Training Time

We trained this model on a 5070 Ti in about 20 minutes