| --- |
| license: mit |
| base_model: microsoft/FastContext-1.0-4B-SFT |
| pipeline_tag: text-generation |
| tags: |
| - core-ai |
| - coreml |
| - on-device |
| - ios |
| - iphone |
| - qwen3 |
| language: |
| - en |
| --- |
| |
| # FastContext-1.0-4B-SFT — Core AI (on-device, iPhone) |
|
|
| [microsoft/FastContext-1.0-4B-SFT](https://huggingface.co/microsoft/FastContext-1.0-4B-SFT) |
| converted to Apple **Core AI** for on-device inference, served by the **CoreAIChat** app. |
|
|
| FastContext is a long-context **repository-exploration agent** (Qwen3-4B-Instruct |
| backbone, supervised-fine-tuned on exploration traces: broad first-turn search, |
| multi-turn evidence gathering, and precise file:line citation generation). |
|
|
| ## Contents |
| - `gpu/` — AOT-compiled **GPU (MPSGraph)** bundle, 4-bit linear-INT4, **h18p** |
| (iPhone 17 / iPhone 18 class). ~2.1 GB. Drop-in for CoreAIChat's |
| `Documents/models/fastcontext_4b_gpu`. |
|
|
| > **Device class:** this is an **AOT h18p** bundle (iPhone 17 / 18 class). On-device |
| > specialization of a 4B graph is not viable, so the bundle is precompiled for the |
| > h18p GPU — the same approach Core AI uses for the Gemma-4B bundle. |
|
|
| ## Verified on iPhone 17 Pro (iOS 27) |
| - **Parity** vs HF fp16 (teacher-forced): **23/24 argmax**, perplexity 1.41 — the |
| single flip is a near-tie quant-noise position. |
| - **On-device GPU:** ~**334 tok/s** prefill, ~**16.5 tok/s** decode (512-prompt / |
| 1024-gen), load ~8 s cold, ~0.3 GB resident (weights memory-mapped). |
|
|
| ## Use |
| Install **CoreAIChat**, open the model picker, and select **FastContext 4B**. |
|
|
| ## License |
| MIT, inherited from the base model |
| [microsoft/FastContext-1.0-4B-SFT](https://huggingface.co/microsoft/FastContext-1.0-4B-SFT). |
| See `LICENSE`. |
|
|
