- Tiny footprint, real accuracy. 1B parameters, adapter under 100 MB — deployable anywhere a 7B+ model can't go: mobile apps, browser extensions, IoT/embedded agents, offline assistants, cost-sensitive high-throughput API backends.
- Purpose-built for agentic tool use. Trained specifically to parse a tool/function schema plus a natural-language user request and emit a correctly-named, correctly-structured, correctly-valued function call — the core skill every LLM agent framework (LangChain, LlamaIndex, AutoGen, CrewAI, custom ReAct loops, MCP servers) depends on.
- Two-stage training: QLoRA SFT + GRPO reinforcement learning. Most open tool-calling fine-tunes stop at supervised fine-tuning. This adapter adds GRPO (Group Relative Policy Optimization) RL on top, specifically rewarding exact function-name selection and exact argument-value correctness — the two hardest, most failure-prone parts of tool calling for small models.
- Honestly measured, not marketing numbers. Every metric comes from one evaluation harness run end-to-end on a locked, held-out 300-example test split — same parser, same grader, same slice for the base model, the SFT model, and this GRPO-refined v3 adapter.
- Compared to GPT-4o / Claude for function calling: 100% free, fully local, zero per-call cost, fine-tunable, data never leaves your machine.
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Tiny footprint, real accuracy. 1B parameters total, LoRA adapter itself is under 100MB — deployable anywhere a 7B+ model can't go: mobile apps, browser extensions, IoT/embedded agents, offline assistants, cost-sensitive high-throughput API backends.
-
Purpose-built for agentic tool use. Trained specifically to parse a tool/function schema plus a natural-language user request and emit a correctly-named, correctly-structured, correctly-valued function call — the core skill every LLM agent framework (LangChain, LlamaIndex, AutoGen, CrewAI, custom ReAct loops, MCP servers) depends on.
-
Two-stage training pipeline: QLoRA SFT + GRPO reinforcement learning. Most open tool-calling fine-tunes stop at supervised fine-tuning. This adapter goes a step further with GRPO (Group Relative Policy Optimization) reinforcement learning on top of the SFT checkpoint, specifically rewarding exact function-name selection and exact argument-value correctness — the two hardest, most failure-prone parts of tool calling for small models.
-
Honestly measured, not marketing numbers. Every metric below comes from one single evaluation harness run end-to-end on a locked, held-out 300-example test split — same parser, same grader, same slice, for the base model, the SFT model, and this GRPO-refined v3 model. No cherry-picked runs, no mixed benchmarks.
Results
Evaluated on a held-out 300-example test slice drawn from a seeded shuffle of ToolACE (see Split integrity).
The base-model column is the same model with the same prompt and no adapter.
The published weights are SFT + GRPO (see GRPO / RLVR). The SFT column is kept because every
negative result below is measured against it.
Table with columns: metric, v2 (previous release), SFT retrain (pre-GRPO), v3 = SFT + GRPO (published)| metric | v2 (previous release) | SFT retrain (pre-GRPO) | v3 = SFT + GRPO (published) |
|---|
parseable — output is a well-formed call | 0.9933 | 1.0000 | 1.0000 |
valid_name — name exists among the offered tools | 0.9700 | 0.9867 | 0.9867 |
expected_name — name matches gold | 0.9067 | 0.9567 |
GRPO buys +0.0100 on args_exact, the metric that matters here, and gives back 0.0034 (one test example
each) on expected_name and arg_key_overlap. That trade is reported rather than hidden: the mean moves
only +0.0006, so this is a targeted gain on the hardest metric, not a broad improvement.
Full 8-metric benchmark (held-out test set, n=300)
This table mirrors the evaluation format from v2 and shows Base, v2, and v3 side-by-side
across all 8 metrics using a single consistent harness and held-out test slice:
Table with columns: Metric, Base MiniCPM5-1B, v2 (previous release), v3 (this model), Delta (v2 → v3)| Metric | Base MiniCPM5-1B | v2 (previous release) | v3 (this model) | Delta (v2 → v3) |
|---|
| parseable_rate | 0.0133 | 0.9933 | 1.0000 | +0.0067 |
| valid_name_rate | 0.0133 | 0.9700 | 0.9867 | +0.0167 |
| expected_name_rate | 0.0133 | 0.9267 | 0.9533 | +0.0267 |
What the additional metrics mean:
no_schema_copy_rate — the model did not copy the tool schema's own field description
verbatim into an argument value.
no_repetition_rate — the completion did not contain a duplicated function-call block or
degenerate repeated-phrase loop. This model has a known weakness here: it often continues
generating filler content after the tool call completes. Use a parser that extracts the first
completed <function>...</function> block.
stopped_cleanly_rate — the model naturally stopped immediately after the completed
</function> tag with no trailing tokens. Use a parser that treats the first completed
<function>...</function> block as the action boundary — do not rely on natural end-of-generation.
Model details
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Base model: openbmb/MiniCPM5-1B — a compact, efficient, Llama-architecture 1B-parameter language model from OpenBMB, ideal for resource-constrained inference, edge computing, and low-latency serving.
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Adapter type: LoRA (Low-Rank Adaptation) via PEFT, rank r=32, alpha=64, dropout=0.05
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Target modules: q_proj, k_proj, v_proj, o_proj, gate_proj, up_proj, down_proj (full attention + MLP coverage)
Quickstart
from transformers import AutoModelForCausalLM, AutoTokenizer
from peft import PeftModel
base = AutoModelForCausalLM.from_pretrained("openbmb/MiniCPM5-1B")
tok = AutoTokenizer.from_pretrained("openbmb/MiniCPM5-1B")
model = PeftModel.from_pretrained(base, "ewinregirgojr/MiniCPM5-1B-Agentic-Tooluse-QLoRA-v3")
Prefer not to deal with adapter loading, or want a single-file local build? See the related repos below for a merged full-weight checkpoint and quantized GGUF files for llama.cpp / Ollama / LM Studio.
Ideal use cases
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Local, private, offline AI agents that need to call tools/APIs without sending data to a cloud LLM provider
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Home automation and smart-home assistants (small enough to run on a Raspberry Pi-class device or a home server)
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Mobile and embedded applications where a 7B+ model is impractical
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High-throughput, cost-sensitive backend services orchestrating many tool calls per request
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Any LangChain / LlamaIndex / AutoGen / MCP-based agent that needs a cheap, fast, locally-hostable function-calling backbone
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Research and experimentation on small-model reasoning, LoRA fine-tuning, and RL-based (GRPO) post-training for structured generation
Base model architecture
MiniCPM5-1B uses a standard LlamaForCausalLM architecture:
Table with columns: Property, Value| Property | Value |
|---|
| Parameters (total) | 1,080,632,832 |
| Parameters (non-embedding) | 679,552,512 |
| Architecture | LlamaForCausalLM |
| Layers | 24 |
| Attention heads (GQA) | 16 Q / 2 KV |
| Context length | 131,072 tokens |
| Training | SFT → RL (GRPO) fine-tune on openbmb/MiniCPM5-1B |
Thinking mode
MiniCPM5-1B has a built-in <think>...</think> chat template. The same checkpoint can act as a fast assistant or a deliberate chain-of-thought reasoner — controlled by a single flag:
prompt = tokenizer.apply_chat_template(
messages, tools=tools, add_generation_prompt=True,
enable_thinking=False,
tokenize=False,
)
prompt = tokenizer.apply_chat_template(
messages, tools=tools, add_generation_prompt=True,
enable_thinking=True,
tokenize=False,
)
Important: always use enable_thinking=False for tool/function calling. With thinking ON the model spends its token budget inside <think>...</think> and may not reach a completed function call. All benchmark numbers in this card use thinking OFF.
Citation
If you use this model, please cite the base model paper:
@article{minicpm4,
title = {MiniCPM4: Ultra-Efficient LLMs on End Devices},
author = {MiniCPM Team},
journal = {arXiv preprint arXiv:2506.07900},
year = {2025}
}
And the ToolACE dataset used for fine-tuning:
@article{toolace,
title = {ToolACE: Winning the Points of LLM Function Calling},
author = {Liu, Ying and others},
journal = {arXiv preprint arXiv:2409.00920},
year = {2024}
}
ModelScope
The base model is also available on ModelScope (for users in China and East Asia):
(The fine-tuned adapter/GGUF builds are currently HuggingFace-only.)
v3 model family (this release)
Previous releases
FAQ
Is this a full model or an adapter? This repo is a LoRA adapter — small, fast to download, must be loaded on top of the base MiniCPM5-1B model via PEFT. If you want a single ready-to-serve checkpoint, use the Merged-FP16 or GGUF repos linked above instead.
Can I run this on CPU / a laptop / a phone? Yes — the whole point of a 1B-parameter model is that it's small enough for CPU inference, laptops, and (via the GGUF quantized builds) even lower-power edge devices.
How does this compare to using GPT-4o / Claude for function calling? This model trades some absolute accuracy for massive gains in cost, latency, privacy, and deployability — you get a locally-hostable, fine-tunable, fully open-weight alternative for agentic tool-use workloads where sending every request to a large hosted API isn't practical or affordable.
What license is this under? Apache 2.0, matching the base model.
Base model
Built on MiniCPM5-1B by OpenBMB.
Limitations