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Pyrex 8B Instruct Uncensored — a sharp, uncensored coding model.
Strong at code · honest by design · runs anywhere.

Model · Benchmarks · Usage · GGUF · Training


Introduction

Pyrex 8B Instruct Uncensored is a real, trained model — built with our own data recipe, our own QLoRA fine-tune, and our own evaluation pipeline on Hugging Face GPU compute. It is a coding-first instruction model designed for real developer work: writing code, fixing bugs, explaining technical problems, and driving agent loops.

Key strengths

  • Coding-first — trained mostly on high-quality code instructions (OpenCoder real-user data, CodeAlpaca, evol-codealpaca), so it writes clean and correct code.
  • Uncensored — answers directly and honestly, without refusals.
  • Agentic / tool-use ready — function-calling data was part of training; suited for OpenAI-compatible APIs and agent workflows.
  • Portable — full-precision safetensors plus GGUF quants for Ollama, llama.cpp and LM Studio.

Uncensored usage note. This model has no safety-alignment softening built in. It can produce content that is explicit, offensive, or otherwise unsuitable for some audiences. Use it responsibly and at your own discretion — the model and its authors assume no liability for outputs.

Model details

Property Value
Parameters 7.6B
Architecture Transformers · RoPE · SwiGLU · RMSNorm · GQA
Context window Up to 32k native (trained at 3072)
Base Coding-specialized instruct model (uncensored variant)
Method QLoRA (4-bit NF4) + LoRA r=48, α=96
Chat format chatml (`<
License Apache-2.0

Benchmarks

Measured with greedy pass@1 on HumanEval — 164 unseen problems, official unit tests executed in a sandbox. No sampling luck, no leaked answers.

HumanEval benchmark

Model HumanEval pass@1
Base (untuned) 29.3% (48/164)
Pyrex (previous) 41.5% (68/164)
Pyrex 8B Instruct Uncensored 52.4% (86/164)

+23.1 points over the base on unseen problems.

Usage

Requirements

  • transformers >= 4.44 for best apply_chat_template support.
  • Any recent PyTorch build (CUDA or CPU).

Python

from transformers import AutoModelForCausalLM, AutoTokenizer

model_id = "ImposterOnline/Pyrex-8B-Instruct-Uncensored"
tok = AutoTokenizer.from_pretrained(model_id)
model = AutoModelForCausalLM.from_pretrained(model_id, device_map="auto", torch_dtype="auto")

messages = [{"role": "user", "content": "Explain async/await in Python."}]
text = tok.apply_chat_template(messages, tokenize=False, add_generation_prompt=True)
out = model.generate(**tok(text, return_tensors="pt"), max_new_tokens=512)
print(tok.decode(out[0], skip_special_tokens=True))

Chat format is chatml. System prompt is optional; when used it is a system message before the user turn.

Server / agentic

Works with any OpenAI-compatible server (vLLM, llama.cpp server, Ollama, Text Generation Inference). Function calling was part of training.

vllm serve ImposterOnline/Pyrex-8B-Instruct-Uncensored

GGUF

Quantized builds live in Pyrex-8B-Instruct-Uncensored-GGUF.

File Size Notes
pyrex-q4_k_m.gguf 4.4 GB Fast, recommended daily driver
pyrex-q5_k_m.gguf 5.1 GB Higher quality
pyrex-q8_0.gguf 8.1 GB Fast, best quality
pyrex-f16.gguf 15.2 GB Full precision
# Ollama (Modelfile ships in the GGUF repo)
ollama create pyrex-8b -f Modelfile
ollama run pyrex-8b "Write a Python function that merges overlapping intervals."

# llama.cpp
./llama-cli -m pyrex-q4_k_m.gguf \
  -p "<|im_start|>user\nYour question here\n<|im_end|>\n<|im_start|>assistant\n" \
  -n 512 -c 8192

Training

Parameter Value
Data ~95k cleaned examples (code + tool-use + general)
Sequence length 3072
Loss masking Assistant-only (completion-only SFT)
Optimizer AdamW · lr 2e-4 · cosine · warmup 3%
Epochs 1
Hardware Hugging Face A100 GPU job

Data sources (credited): OpenCoder-LLM/opencoder-sft-stage1 (realuser + largescale-diverse), sahil2801/CodeAlpaca-20k, theblackcat102/evol-codealpaca-v1, databricks/databricks-dolly-15k, NousResearch/hermes-function-calling-v1.

The pipeline is config-driven and reproducible — prepare_data.py → train_qlora.py → eval_humaneval.py → publish.sh — in the companion repo Arhan-w/pyrut.

License

Apache-2.0.

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Evaluation results