MiniCPM5-2B — Core AI int8 bundle (dynamic, pipelined engine)

94716b4 verified about 8 hours ago

9.03 kB

license: apache-2.0
base_model: openbmb/MiniCPM5-2B
pipeline_tag: text-generation
library_name: coreai
tags:
  - coreai
  - core-ai
  - coreml
  - apple
  - on-device
  - iphone
  - metal
base_model_relation: quantized

Core AI is Apple's on-device ML runtime in iOS 27 / macOS 27 and the successor to Core ML: PyTorch models are exported with Apple's coreai-torch (LLMs: coreai.llm.export) into .aimodel bundles that run on the GPU or the Neural Engine, e.g. Qwen3-8B 4-bit decodes at 94 tok/s on an M4 Max GPU, MLX 90 under the same protocol (apple-silicon-llm-bench, macOS 27 beta, 2026-06).

This model has no row on DeviceMark, the on-device LLM leaderboard.

MiniCPM5-2B — Core AI (int8 block-32, runs on iPhone)

Apple Core AI (.aimodel) conversion of openbmb/MiniCPM5-2B — OpenBMB's 2.5B on-device LLM (released 2026-09-06, the 1B's 42-layer sibling) with hybrid Think / No-Think reasoning, native tool calling and 128K context; OpenBMB reports it as 2B-class open-source SOTA (LiveCodeBench v6 69.1, AIME 2026 86.5, BFCL v4 66.6, SWE-bench Verified 46.4 on their card). Runs fully on-device on iPhone and Apple Silicon Macs (GPU, pipelined engine).

Part of the community Core AI model zoo: https://github.com/john-rocky/coreai-model-zoo

Use it

⚡ One line — run the kit's task op on this model (import CoreAIOps; no session, no model plumbing, downloads on first use):

let tldr = try await CoreAI.summarize(text, options: .model("minicpm5-2b"))

Every op, one shape — Cookbook.

▶️ Run it (source) — the ChatDemo runner (GUI + CLI, one app for every chat model in the catalog):

git clone https://github.com/john-rocky/coreai-kit
open coreai-kit/Examples/ChatDemo/ChatDemo.xcodeproj
# → Run, then pick "MiniCPM5 2B" in the model picker

# agents / headless (macOS):
cd coreai-kit/Examples/ChatDemo
swift run chat-cli --model minicpm5-2b --prompt "What can you do, offline?"

💻 Build with it — complete; the glue is kit API, copy-paste runs:

import CoreAIKit

let chat = try await ChatSession(catalog: "minicpm5-2b")
let reply = try await chat.respond(to: prompt)
// reply: the answer, generated fully on-device

The take-home is Examples/ChatDemo/Sources/QuickStart.swift — this exact code as one typed function, no UI; the CLI is an argument shell over it, and the GUI drives the same ChatSession across turns for its transcript. Multi-turn? Hold the ChatSession and call respond(to:) per turn — it keeps the conversation history; streamResponse(to:) yields tokens as they decode.

Integration checklist

SPM: https://github.com/john-rocky/coreai-kit → product CoreAIKit
Info.plist: none needed
Entitlements: none on Mac; iPhone needs com.apple.developer.kernel.increased-memory-limit (the 2.7 GB cold specialization passes the default jetsam limit)
First run downloads the model — 2.7 GB (Mac) / 2.7 GB (iPhone) — then it loads from the local cache (Application Support; progress via the downloadProgress callback)
Measure in Release — Debug is ~3× slower on per-token host work

Measured

	decode	prefill	numerics	size
iPhone 17 Pro (A19 Pro, `PipelinedBench`, Release)	22.4 tok/s	27.3 tok/s	24/24 + 24/24 token-exact vs HF fp32 (nat + oracle, the margin-clean alphabet prompt); engine ready 28.9 s cold	2.7 GB
M4 Max (macOS 27, `llm-benchmark`)	127.6 tok/s	2654 tok/s	16/16 token-exact vs the fp32 oracle (margin-aware gate, min margin 0.925)

Free-run check (4 prompts × 30 greedy tokens vs fp32 HF, verify_minicpm5.py): 3/4 exact; the one miss is a name at fp32 probability 0.2126 vs 0.2065 (Emma/Lily, top-2 margin 0.006) — a tie any precision may flip. The fp16 control export scores 4/4, and the per-channel int8 sibling of this bundle scored 2/4 with a real 0.245-margin flip (,→ and), which is why this repo ships per-block-32 scales instead (same recipe, three YAML lines; see Quantization).

⚠️ iPhone context cap: prompt + generated tokens must stay under 1024. The bundle declares a 131072 dynamic KV, and the shipped CoreAIPipelinedEngine caps iOS growing-KV capacity at 1024 (its guard against the iOS compiler miscompiling growing-KV specializations at seq ≥ 2048) — so a phone conversation truncates at absolute position 1024. Chunk or trim the history on iOS; macOS has no cap.

Same recipe as the published MiniCPM5-1B (int8 66.8 tok/s on the same phone) with one YAML changed — per-block-32 scales instead of per-channel. Measured on the Mac before picking it (llm-benchmark, 512p/1024g): int8 per-channel 25.6 tok/s, fp16 80.0, int8 per-block-32 127.6. Per-channel int8 lowers to a slow dequant path on the Mac GPU; block-32 lands on the fast quantized-matmul path, 5× the per-channel decode and 1.6× fp16's, at +155 MB. On the phone the two decode the same (bandwidth-bound), so block-32 wins on both.

Quantization

Weight-only symmetric int8, per-block-32 (a scale per 32-wide block along the input dim; no clipping), applied as a torch pre-export pass via coreai-opt; SDPA / RoPE / RMSNorm stay full precision. The 1B ships the per-channel version of the same config.

uv run coreai.llm.export openbmb/MiniCPM5-2B --experimental --compute-precision float16 \
  --compression-config minicpm5_int8sym_b32.yaml
# minicpm5_int8sym_b32.yaml: quantization_config → op_state_spec.weight = {dtype: int8,
#   qscheme: symmetric, granularity: {type: per_block, block_size: 32}}

Conversion notes

llama → mistral remap. MiniCPM5-2B's model_type is llama (a plain LlamaForCausalLM: 42 layers × hidden 2048, GQA 16:2, head_dim 128, RoPE θ 5e6, untied 130560-vocab head); the stock exporter has no llama graph family, but Mistral's builder is architecturally identical for this config (GQA, no qkv bias, no qk-norm, explicit head_dim honored). One-line remap in the model registry — the same line that ships the 1B.
Chat EOS. Base eos_token is </s>, but the chat template ends turns with <|im_end|> (id 130073). The bundle's tokenizer eos_token is set to <|im_end|> (as Qwen ships) so generation halts cleanly — checked through the engine with the chat template applied: the model thinks, answers, and stops (124-token reply, 131.6 tok/s short-context on the M4 Max, on the published bundle).
Dynamic-shape bundle → the Core AI pipelined engine (the iPhone path); a static iOS export routes to the static-shape engine instead, which this FM-format bundle doesn't target. The 2.67 GB single-file bundle cold-specializes on the phone in 28.9 s (no AOT); that step needs the increased-memory entitlement and ~3 GB of free phone storage.
Thinking. The model thinks by default (<think>…</think> before the answer); pass enable_thinking=False through the chat template for a direct answer. Give generation a generous budget (the kit caps at 4096) — the think trace alone can run several hundred tokens.

Run

import FoundationModels
import CoreAILanguageModels
let model = try await CoreAILanguageModel(resourcesAt: int8BundleURL)   // …/int8
let session = LanguageModelSession(model: model)
print(try await session.respond(to: "Explain on-device AI in one sentence."))

Or in the zoo's CoreAIChat app / the kit's ChatDemo (Model → "MiniCPM5 2B").

Reproduce

Exporter, gate, card and port notes live in the Core AI model zoo: models/minicpm5-2b/, conversion/export_minicpm5.py, knowledge/minicpm5-1b.md.

python3 conversion/zoo_convert.py show minicpm5-2b
python3 conversion/zoo_convert.py run  minicpm5-2b

Credits

Model: MiniCPM5-2B by OpenBMB (openbmb/MiniCPM5-2B, Apache-2.0). Core AI conversion: the Core AI model zoo.