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This checkpoint is a derivative of google/gemma-3-4b-it. Lexsi Labs' modifications are licensed under the Lexsi Labs Source Available License (LSAL) v1.2 (https://github.com/Lexsi-Labs/SafeTune/blob/main/LICENSE.md), a noncommercial license; organizational use requires the acknowledgement or permission described in its Section 1A. The base-model material remains subject to the Gemma Terms of Use, and you must not use this model for any use restricted by Gemma Terms of Use Section 3.2.

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Gemma-3-4B-it SafeTune code SFT drift

Safety-degraded checkpoint. This model is intentionally less safe than its base. Do not deploy it in a production, user-facing, or agentic system (LSAL Section 4).

google/gemma-3-4b-it fine-tuned (SFT) on code data. The fine-tune erodes the model's safety behaviour (safety drift). SafeTune uses this checkpoint to measure drift and to test recovery methods.

This checkpoint is a research artifact released with SafeTune for reproducing safety-drift and recovery experiments.

Base model google/gemma-3-4b-it
Role SFT drift (safety-degraded)
Developed by Lexsi Labs (Lithasa Technologies Pvt. Ltd.)
License LSAL v1.2 (Lexsi modifications) + base-model license; see License
Contact support@lexsi.ai

Usage

import torch
from transformers import AutoModelForCausalLM, AutoTokenizer

model_id = "Lexsi/gemma3-4b-code-sft-drift"
tokenizer = AutoTokenizer.from_pretrained(model_id)
model = AutoModelForCausalLM.from_pretrained(model_id, dtype=torch.bfloat16, device_map="auto")

messages = [{"role": "user", "content": "Explain what a hash function is in two sentences."}]
inputs = tokenizer.apply_chat_template(messages, add_generation_prompt=True, return_tensors="pt", return_dict=True).to(model.device)
out = model.generate(**inputs, max_new_tokens=256, do_sample=False)
print(tokenizer.decode(out[0][inputs["input_ids"].shape[-1]:], skip_special_tokens=True))

License

This is a derivative work of google/gemma-3-4b-it; the NOTICE file states the modification.

  • Lexsi Labs' modifications are licensed under the Lexsi Labs Source Available License (LSAL) v1.2: free for academic research and teaching; organizational use requires acknowledgement or permission (Section 1A); commercial use requires a separate license (Section 2); drifted checkpoints may not be deployed in production (Section 4).
  • The base-model material remains subject to the Gemma Terms of Use, including the use restrictions in its Section 3.2 and the Gemma Prohibited Use Policy, which apply to this model.

Files: LICENSE-LSAL-1.2.md, NOTICE

  • GEMMA_TERMS_OF_USE.md

Citation

@inproceedings{seth2026safetune,
  title     = {SafeTune: A Unified, Faithful Library for Auditing and
               Repairing Safety Drift in Fine-Tuned {LLM}s},
  author    = {Seth, Pratinav and Sadhu, Saisab and Kaushal, Anshul and
               Sankarapu, Vinay Kumar},
  booktitle = {Proceedings of the 2026 Conference on Empirical Methods in
               Natural Language Processing: System Demonstrations},
  publisher = {Association for Computational Linguistics},
  year      = {2026}
}
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