openbmb/minicpm

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✨ Highlights

We are releasing MiniCPM5-2B, the second model in the MiniCPM5 series, following MiniCPM5-1B. It is a dense 2B Transformer that scales up the same training recipe, built for on-device, local deployment, and resource-constrained scenarios, reaching 2B-class open-source SOTA.

🏆 2B-class open-source SOTA: compared with strong open-source models of similar size, MiniCPM5-2B achieves SOTA performance within this comparison set. It remains competitive with 4B-class models overall, while showing its advantages over models of comparable size in coding, mathematics, long-context understanding, tool use, and agentic tasks.

📂 Open High-Quality Data: Alongside the model, we are releasing the high-quality training datasets behind it as part of the UltraData family: UltraX, a high-quality web pre-training dataset; UltraData-Code, featuring L0–L3 tiered code data management to drive a significant leap in coding capabilities; UltraData-SFT-Agent-2609, comprising 500K agent training samples to enhance comprehensive on-device agent capabilities; and UltraData-RL-2609, with 80K+ high-quality RL training samples covering mathematics, code, general knowledge, and long-context reasoning.

🔥 Changelog

• 📌 [2026.09.07] MiniCPM5-2B is released: a compact 2B-class dense model for on-device and resource-constrained use, paired with deployment / fine-tuning Agent Skills.
• [2026.05.19] MiniCPM5-1B is released: a compact 1B-class dense model for on-device and resource-constrained use, paired with deployment / fine-tuning Agent Skills.
• [2026.02.11] MiniCPM-SALA is released: a sparse-and-linear hybrid attention model for million-token context modeling and efficient inference.
• [2025.09.05] MiniCPM4.1 series is released: a trainable sparse-attention model with hybrid reasoning.
• [2025.06.06] MiniCPM4 is released: an end-side model with over 5x generation acceleration on typical edge chips.

🧭 Quick Links

• ✨ Highlights
• 🔥 Changelog
• 📦 Model Downloads
• 🚀 MiniCPM5-2B
  • Introduction
  • Evaluation Results
  • Training Recipe
    • What does RL + OPD bring?
  • Quickstart
  • Deployment and Fine-tuning Cookbooks and Agent Skills
  • Other Supported Frameworks
• 🚀 MiniCPM5-1B
• 🧪 MiniCPM-SALA
• ⚡ MiniCPM4 & MiniCPM4.1 Series
• Legacy topics →: BitCPM4 quantization, MiniCPM4 applications
• 📄 LICENSE · 🏛 Institutions · 📚 Citation

📦 Model Downloads

Current release: MiniCPM5-2B / MiniCPM5-1B（BF16 / GGUF / MLX）：

MiniCPM5-2B

MiniCPM5-1B

Other key releases:

🚀 MiniCPM5-2B

Introduction

MiniCPM5-2B is the second checkpoint in the MiniCPM5 series, scaling the MiniCPM5-1B recipe up to 2B parameters for users who can afford a larger footprint in exchange for stronger capability. It is designed for local assistants, coding agents, tool-use workflows, and reasoning scenarios where a compact model is preferred. The model keeps a small deployment footprint while providing native long-context support.

Evaluation Results

We compare MiniCPM5-2B with strong open-source models in the same size class, including LFM2.5-2.6B, Qwen3.5-2B, and Gemma-4-E2B-it, while also listing larger models such as Qwen3.5-4B, granite-4.2-3B, Nemotron-3-Nano-4B, Gemma-4-E4B-it, and LFM2.5-8B-A1B for reference.

Within this comparison set, MiniCPM5-2B reaches 2B-class open-source SOTA with an average score of 53.9, and also exceeds all of the larger models included here (the highest is 51.1). Its advantages are most visible in code reasoning, math reasoning, long-context understanding, tool use, and multiple agentic tasks.

Training Recipe

The training of MiniCPM5-2B is a full-stack practice of UltraData Tiered Data Management, covering three stages: base training, mid-training, and post-training.

During base training, the model goes through stable training and decay training to build core language capability and training stability. It then enters mid-training to further strengthen target capabilities and adapt to the target data distribution. The training corpus is released alongside the model as Ultra-FineWeb, Ultra-FineWeb-L3, UltraX, UltraData-Code and UltraData-Math.

During post-training, we proceed in three steps: SFT, RL, and OPD. We first use 400B tokens of deep-thinking SFT to establish deep-thinking and general chat abilities; the SFT data is released as UltraData-SFT-2605 and Agent SFT data as UltraData-SFT-Agent-2609. We then train specialized RL teachers for math, code, agentic tasks, writing, and related domains(with the corresponding data also open-sourced as UltraData-RL-2609), and use On-Policy Distillation (OPD) to distill these teachers back into one release model.

What does RL + OPD bring?

RL + OPD is a key part of MiniCPM5-2B post-training. During the RL stage, we adopted the critic-based algorithm described in JustRL II, substantially improving training stability and achieving significant gains across multiple domains. On the benchmarks listed below, RL + OPD improves reasoning and general capabilities by an average of ↑10.96 points, and agentic capabilities by ↑6.96 points.

OPD merges the capabilities of 16 expert models produced by RL training, including 5 agentic expert models. At each response position, we compute the full-vocabulary reverse KL divergence between student and teacher logits as the advantage estimate, replacing the original verification-based advantage. OPD directly reuses the prompts used to train each RL teacher as distillation data, so no additional corpus construction is required.

Quickstart

We recommend using the following sets of sampling parameters for generation: temperature=1.0, top_p=0.95, min_p=0.0.

If you encounter repetitive outputs, try: temperature=1.0, top_p=0.95, min_p=0.0, repetition_penalty=1.05.

Please note that the support for sampling parameters varies according to inference frameworks.

vLLM

pip install "vllm>=0.21"
vllm serve openbmb/MiniCPM5-2B --port 8000

curl http://localhost:8000/v1/chat/completions \
  -H "Content-Type: application/json" \
  -d '{
    "model": "openbmb/MiniCPM5-2B",
    "messages": [{"role": "user", "content": "Who are you? Please briefly introduce yourself."}],
    "max_tokens": 128,
    "temperature": 1.0, "top_p": 0.95
  }'

SGLang

pip install "sglang[srt]>=0.5.16"
python -m sglang.launch_server --model-path openbmb/MiniCPM5-2B --port 30000

curl http://localhost:30000/v1/chat/completions \
  -H "Content-Type: application/json" \
  -d '{
    "model": "openbmb/MiniCPM5-2B",
    "messages": [{"role": "user", "content": "Who are you? Please briefly introduce yourself."}],
    "max_tokens": 128,
    "temperature": 1.0, "top_p": 0.95
  }'

Speculative decoding (DSpark): we also release MiniCPM5-2B-DSpark, a DSpark draft model trained for MiniCPM5-2B. Enable it in SGLang to accelerate decoding while keeping the target model’s outputs unchanged:

python -m sglang.launch_server \
  --model-path openbmb/MiniCPM5-2B \
  --trust-remote-code \
  --speculative-algorithm DSPARK \
  --speculative-draft-model-path openbmb/MiniCPM5-2B-DSpark \
  --speculative-dspark-block-size 7 \
  --port 30000

Llama.cpp

llama-server -m MiniCPM5-2B-F16.gguf -a MiniCPM5-2B --port 8080 -ngl 99 -c 8192 --jinja

-c 8192 sets the context length. You can adjust this value as needed.

curl http://localhost:8080/v1/chat/completions \
    -H "Content-Type: application/json" \
    -d '{
        "model": "MiniCPM5-2B",
        "messages": [{"role": "user", "content": "1+1=?"}],
        "temperature": 1.0, "top_p": 0.95, "min_p": 0.0, "max_tokens": 256
    }'

In llama.cpp, the default min_p=0.05 can lead to repetitive output: it filters out tokens whose probability is below 5% of the highest-probability token, potentially discarding the exact tokens needed to break out of a repetition loop. To prevent this, we set min_p=0.0.

Transformers

pip install -U "transformers>=5.6" accelerate torch

from transformers import AutoModelForCausalLM, AutoTokenizer
model_id = "openbmb/MiniCPM5-2B"
tokenizer = AutoTokenizer.from_pretrained(model_id)
model = AutoModelForCausalLM.from_pretrained(
    model_id,
    torch_dtype="auto",
    device_map="auto",
)
messages = [{"role": "user", "content": "Who are you? Please briefly introduce yourself."}]
inputs = tokenizer.apply_chat_template(
    messages,
    tokenize=True,
    add_generation_prompt=True,
    enable_thinking=True,
    return_dict=True,
    return_tensors="pt",
).to(model.device)
outputs = model.generate(**inputs, max_new_tokens=128)
print(tokenizer.decode(outputs[0][inputs["input_ids"].shape[-1]:], skip_special_tokens=True))

Tool Calling

For tool / function calling, SGLang is the recommended backend. MiniCPM5-2B emits XML-style tool calls and SGLang’s built-in minicpm5 parser converts them to OpenAI-compatible tool_calls natively:

python -m sglang.launch_server --model-path openbmb/MiniCPM5-2B --port 30000 \
    --tool-call-parser minicpm5      # or: --tool-call-parser auto

GitHub Cookbooks and Agent Skills

MiniCPM5-2B uses the standard LlamaForCausalLM architecture, so mainstream inference engines can load it directly: no custom kernels, no model-code fork. For step-by-step deployment and fine-tuning instructions, use the GitHub cookbooks below. Agent Skills are linked as GitHub resources for users working with Cursor / Claude Code style coding agents.

Deployment

Fine-tuning

Other Supported Frameworks

In addition to the deployment and fine-tuning frameworks listed above, MiniCPM5-2B is also supported by FlagOS for multi-chip deployment.

FlagOS Overview

To enable large-scale deployment across different AI chips, Beijing Zhiyuan Research Institute, together with numerous research institutions, chip manufacturers, system vendors, and algorithm and software organizations both domestically and internationally, jointly initiated and established the FlagOS Open Source Community.

The FlagOS community is dedicated to building a unified, open-source system software stack for various AI chips, encompassing core open-source projects such as a large-scale operator library, a unified AI compiler, parallel training and inference frameworks, and a unified communication library. It aims to create an open technology ecosystem connecting the “model-system-chip” layers. By enabling “develop once, deploy across chips”, FlagOS unlocks the computational potential of hardware, breaks down the ecosystem silos between different chip software stacks, and effectively reduces migration costs for developers.The FlagOS community fosters an AI hardware and software ecosystem, overcomes single-vendor closed-source monopolies, promotes widespread deployment of AI hardware technologies, and is committed to rooted in China while embracing global collaboration.

Official website express: https://flagos.io

🚀 MiniCPM5-1B

MiniCPM5-1B is the first model in the MiniCPM5 series. It is a dense 1B Transformer built for on-device, local deployment, and resource-constrained scenarios, reaching 1B-class open-source SOTA.

🧪 MiniCPM-SALA

First large-scale Sparse + Linear Attention hybrid for million-token context (2026-02). HuggingFace · ModelScope

⚡ MiniCPM4 and MiniCPM4.1 Series

8B-scale trainable sparse attention with hybrid reasoning (2025-09 / 2025-06). MiniCPM4.1-8B · MiniCPM4-8B · ModelScope

Quantization (BitCPM4) and MiniCPM4 applications (Survey / MCP / Intel AIPC Client): see docs/README-legacy.md.

📄 LICENSE

Model LICENSE

• This repository and MiniCPM models are released under the Apache-2.0 License.

Statement

• As a language model, MiniCPM generates content by learning from a vast amount of text.
• However, it does not possess the ability to comprehend or express personal opinions or value judgments.
• Any content generated by MiniCPM does not represent the viewpoints or positions of the model developers.
• Therefore, when using content generated by MiniCPM, users should take full responsibility for evaluating and verifying it on their own.

🏛 Institutions

This project is developed by the following institutions:

• Modelbest Inc.
• THUNLP
• Gaoling School of Artificial Intelligence of RUC

📚 Citation

• Please cite our paper: MiniCPM4 if you find our work valuable.

@article{minicpm4,
  title={Minicpm4: Ultra-efficient llms on end devices},
  author={MiniCPM, Team},
  journal={arXiv preprint arXiv:2506.07900},
  year={2025}
}