🍰👑 ChatBerry

ChatBerry is the flagship release of the ChatBerry family — a fine-tuned version of artindnr/strawberry-1, converted from a reasoning ("thinking") model into a direct-answer chat model. Reasoning traces are disabled — ChatBerry responds directly, without emitting a separate chain-of-thought / analysis channel. This release is trained on the largest dataset in the ChatBerry line to date, and outperforms every prior checkpoint, including ChatBerry-1.2.

What's New

ChatBerry is the culmination of the iterative ChatBerry line (1.0 → 1.1 → 1.2), each of which scaled up training data over the last:

Trained on the largest dataset yet in the ChatBerry line
Outperforms ChatBerry-1.2 (and by extension the rest of the line) on response quality and instruction-following
Same direct-chat behavior: no visible reasoning/analysis channel
The current recommended default for anyone looking for a ChatBerry checkpoint

Model Details

Base model: artindnr/strawberry-1 (itself fine-tuned from openai/gpt-oss-20b, 21B parameters)
Architecture: gpt_oss
Fine-tuned by: artindnr
License: Apache 2.0
Languages: Farsi (Persian), English, and multilingual support
Model type: Causal decoder-only chat language model (reasoning disabled)

Training

ChatBerry was fine-tuned from artindnr/strawberry-1 on the largest version yet of the direct chat-style (non-reasoning) SFT data used across the ChatBerry line. As with earlier ChatBerry releases, this SFT pass overrides Strawberry-1's reasoning behavior, teaching the model to skip the analysis channel and go straight to a final answer.

How to Use

ChatBerry uses the gpt-oss chat template (Harmony format) shipped with the base model, so it works with 🤗 Transformers.

Installation

pip install torch --index-url https://download.pytorch.org/whl/cu128
pip install "trl>=0.20.0" "peft>=0.17.0" "transformers>=4.55.0" "kernels>=0.12.0"

This has been verified to work with:

Package	Version
`torch`	2.8.0+cu129
`transformers`	5.14.1
`trl`	1.9.2
`peft`	0.20.0
`accelerate`	1.10.1
`tokenizers`	0.22.0

Generation

import torch
from transformers import AutoModelForCausalLM, AutoTokenizer

MODEL_ID = "artindnr/chatberry"

tokenizer = AutoTokenizer.from_pretrained(MODEL_ID)
model = AutoModelForCausalLM.from_pretrained(
    MODEL_ID,
    torch_dtype=torch.bfloat16,
    device_map="auto",
)

USER_PROMPT = "تو کی هستی و اسمت چیه؟"

messages = [
    {"role": "user", "content": USER_PROMPT},
]

inputs = tokenizer.apply_chat_template(
    messages,
    add_generation_prompt=True,
    tokenize=True,
    return_dict=True,
    return_tensors="pt",
).to(model.device)

outputs = model.generate(
    **inputs,
    max_new_tokens=512,
    temperature=0.6,
    do_sample=True,
)

print(tokenizer.decode(outputs[0][inputs["input_ids"].shape[-1]:], skip_special_tokens=True))

As with earlier ChatBerry releases, there's no need to set a reasoning language system message or parse out separate analysis / final channels — ChatBerry goes straight to its final answer, so decoding just the newly generated tokens with skip_special_tokens=True gives you the plain-text response directly.

Intended Use

ChatBerry is intended for:

General-purpose Farsi and multilingual chat assistants
Applications where direct, low-latency responses are preferred over visible reasoning traces
Use cases that want the best-performing, most data-rich ChatBerry checkpoint available

Limitations

ChatBerry trades away Strawberry-1's explicit chain-of-thought reasoning; for tasks that benefit from visible step-by-step reasoning, artindnr/strawberry-1 may be a better fit.
As with any fine-tune, ChatBerry inherits the general capabilities and limitations of the gpt-oss-20b base model and the strawberry-1 checkpoint it was built from, including the possibility of hallucinated facts.
No formal safety fine-tuning beyond what is inherited from the base model and Strawberry-1 has been applied; use appropriate safeguards in production settings.

License

This model is released under the Apache 2.0 license, consistent with the base gpt-oss-20b model and strawberry-1.

Citation

If you use ChatBerry in your work, please cite:

@misc{chatberry,
  title  = {ChatBerry: A Direct-Answer Chat Fine-tune of Strawberry-1},
  author = {artindnr},
  year   = {2026},
  url    = {https://huggingface.co/artindnr/chatberry}
}