MiniCPM5-2B

OpenBMB

Parameters

2.5B

Architecture

LlamaForCausalLM

Released

08.09.2026

License

Apache License 2.0

Open Weights Commercial Use Multimodal BF16 MiniCPM en zh

Input Modalities

text

Output Modalities

text

Context (native)

131,072 tokens

Context (extended)

131,072 tokens

Openness Index Score 100.0/100

About

MiniCPM5-2B (openbmb/MiniCPM5-2B, released September 8, 2026 under the Apache 2.0 License) is the second model in the MiniCPM5 series - a dense 2B Transformer (2.52B parameters) built for on-device, local deployment and resource-constrained scenarios, reaching 2B-class open-source SOTA (average score 53.9 in its comparison set, exceeding even the larger models listed, highest of which scores 51.1). It stays competitive with 4B-class models overall, with advantages in coding, mathematics, long-context understanding, tool use and agentic tasks, and provides native long-context support (128K context).

Its training is a full-stack practice of UltraData Tiered Data Management (arXiv 2602.09003): base training (stable + decay phases) and mid-training build core language and target capabilities on the open Ultra-FineWeb/UltraX/UltraData-Code (L0-L3 tiered)/UltraData-Math corpora; post-training runs SFT (400B tokens of deep-thinking SFT), RL with the critic-based algorithm of JustRL II (scaling small LLMs to 128K reasoning), and On-Policy Distillation (OPD) merging 16 expert models produced by RL (including 5 agentic experts) into one release model via full-vocabulary reverse-KL advantage estimates - improving reasoning/general capabilities by an average of +10.96 points and agentic capabilities by +6.96. All datasets are released as part of the UltraData family.

Training Data UltraData family: UltraX, UltraData-Code (L0-L3 tiered), UltraData-SFT-2605, UltraData-SFT-Agent-2609, UltraData-RL-2609, Ultra-FineWeb, Ultra-FineWeb-L3, UltraData-Math. 400B tokens of deep-thinking SFT.

Benchmark Scores

Benchmark Score Date Standing
Humanity's Last Exam
stem_reasoning
12.88%
—
#59/71
better than 17%
MMLU-Pro
knowledge
34.84%
—
#37/48
better than 23%
BFCL-V4
general_agent
86.26%
—
#7/27
better than 77%
SWE-bench Verified
coding_agent
52.75%
—
#48/60
better than 20%
GPQA Diamond
stem_reasoning
54.43%
—
#67/80
better than 16%
BrowseComp-zh
general_agent
60.36%
—
#5/13
better than 67%
SuperGPQA
knowledge
32.88%
—
#21/28
better than 26%
BrowseComp
general_agent
41.12%
—
#33/45
better than 27%
AA-LCR
long_context
70.24%
—
#29/42
better than 32%
Gaia2
general_agent
100.00%
—
#1/12
better than 100%

Architecture

Decoder Block input Embedding vocab 131K · d 2048 Full Attention GQA 16:2 · dₕ 128 ×42 Dense FFN silu · d 6144 Final Norm LM Head vocab 131K output
Attention
Grouped Query Attention (16:2)
Layers
42
Hidden size
2048
Context
131K tokens
RoPE θ
5M
Parameters
2516.8M

Source: Hugging Face config.json · LlamaForCausalLM · model repo

Type: LlamaForCausalLM
Attention: GQA
Decoder: standard

Training Pipeline

  1. 1
    pretraining

    Base Training (Stable + Decay)

    Base training with stable training and decay training phases to build core language capability and training stability. Uses Ultra-FineWeb, Ultra-FineWeb-L3, UltraX, UltraData-Code, and UltraData-Math corpora.

  2. 2
    sft

    Supervised Fine-Tuning (Deep-Thinking SFT)

    400B tokens of deep-thinking SFT to establish deep-thinking and general chat abilities. Uses UltraData-SFT-2605 and UltraData-SFT-Agent-2609 (500K agent samples).

  3. 3
    rl

    RL + On-Policy Distillation (OPD)

    RL training using critic-based algorithm (JustRL II) for improved stability. Specialized RL teachers for math, code, agentic tasks, writing. OPD merges 16 expert models (5 agentic) using full-vocabulary reverse KL divergence. Uses UltraData-RL-2609 (80K+ samples). RL + OPD improves reasoning by avg +10.96 points and agentic capabilities by +6.96 points.

Training & Evaluation Datasets

NameRoleSizeModalitiesCollection
UltraX-Preview pretraining — text —
UltraData-Code pretraining — text, code —
UltraData-SFT-2605 finetune 400B tokens text —
UltraData-SFT-Agent-2609 finetune 500K samples text —
UltraData-RL-2609 rl 80K+ samples text —
Ultra-FineWeb pretraining — text —

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