README.md

---
license: other
license_name: swift-open-license-1.0
license_link: https://huggingface.co/ukisai/Swift-1.5-4bit-MLX/blob/main/LICENSE
base_model: ukisai/Swift-1.5-Qwen3.8-27b
base_model_relation: quantized
library_name: mlx
pipeline_tag: text-generation
tags:
  - mlx
  - quantized
  - 4-bit
  - affine
  - qwen3_8
---

<div align="center">
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  <div style="display:flex;justify-content:center;gap:0.6em;margin-bottom:1em;">
    <a href="https://ukisai.com"><strong>Website</strong></a> &nbsp;&bull;&nbsp;
    <a href="https://ukisai.com/products/swift"><strong>Learn more</strong></a> &nbsp;&bull;&nbsp;
    <a href="https://huggingface.co/ukisai/Swift-1.5-Qwen3.8-27b"><strong>BF16 model</strong></a> &nbsp;&bull;&nbsp;
    <a href="https://huggingface.co/ukisai/Swift-1.5-Qwen3.8-27B-GGUF"><strong>GGUF</strong></a> &nbsp;&bull;&nbsp;
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    <a href="#evaluation"><strong>Evaluation</strong></a> &nbsp;&bull;&nbsp;
    <a href="#license-and-access"><strong>Enterprise licensing</strong></a>
  </div>
</div>

# Swift 1.5 Qwen3.8-27B — 4-bit MLX

**Apple MLX 4-bit affine quantization.** This is Swift 1.5 in native MLX format,
converted with the official Apple MLX-LM converter using 4 bits and group size 64.
Swift 1.5 is UkisAI's reasoning-efficient Qwen3.8-27B derivative, focused on stronger
long-horizon, agentic and coding performance while using fewer thinking tokens.

Swift 1.5 uses **58.5% fewer thinking tokens** than base Qwen3.8-27B while scoring **0.35% higher**, for a **9.18× speed-up** on several tasks.

## Download the complete model

This repository is public. Download the **whole repository from its root**:

```bash
hf download ukisai/Swift-1.5-4bit-MLX --local-dir Swift-1.5-4bit-MLX
```

Install the CLI and patched runtime using the steps in [USAGE.md](USAGE.md).
The full checkpoint is **15.83 GB (14.74 GiB)** and requires all three files:

| Weight shard | Size |
|---|---:|
| [model-00001-of-00003.safetensors](https://huggingface.co/ukisai/Swift-1.5-4bit-MLX/resolve/main/model-00001-of-00003.safetensors?download=true) | 5,328,325,554 bytes |
| [model-00002-of-00003.safetensors](https://huggingface.co/ukisai/Swift-1.5-4bit-MLX/resolve/main/model-00002-of-00003.safetensors?download=true) | 5,354,185,158 bytes |
| [model-00003-of-00003.safetensors](https://huggingface.co/ukisai/Swift-1.5-4bit-MLX/resolve/main/model-00003-of-00003.safetensors?download=true) | 5,144,253,923 bytes |

You also need the root config, index and tokenizer assets; the command above
downloads them together. The previously exposed **3.87 MB
`real-checkpoint-samples.safetensors` was a diagnostic sample**, not a complete
model. Those test files are now archived under `compatibility/mac-check/fixtures.zip`
to keep them out of model-file discovery. Model weights are unchanged.

**Runtime requirement:** use the included MLX-LM patch and [loading instructions](USAGE.md).
Stock MLX-LM and GUI integrations that cannot apply the patch have not been validated
for this complete checkpoint. Full-model generation on a 24 GB Mac has not been
validated; the weights require additional memory for the runtime, cache and macOS.

## Demo

We gave base Qwen3.8-27B and Swift 1.5 27B the same prompt:

> create a 3d little planet globe where I (player can walk around) and it has all these biomes to explore, the globe doesn't have to be too big, but still fun to go around. It's about a boy scout who is camping and goes around exploring.

<video src="https://huggingface.co/ukisai/Swift-1.5-4bit-MLX/resolve/main/swift-1.5-planet-demo.mp4" controls autoplay muted loop playsinline style="width:100%;height:auto;border-radius:12px;"></video>

Try the game yourself here: [https://ukisai.com/swift-games/27b](https://ukisai.com/swift-games/27b)

Base Qwen3.8-27B took 104.6 minutes to build its game. Swift 1.5 took 11.39 minutes.

## Source and quantization

The conversion used the merged Swift 1.5 BF16 export associated with
[`ukisai/Swift-1.5-Qwen3.8-27b` revision `00ccd14e006897d28cb0ed5bf26390e60d274251`](https://huggingface.co/ukisai/Swift-1.5-Qwen3.8-27b/tree/00ccd14e006897d28cb0ed5bf26390e60d274251).
The source repository was subsequently completed with all 18 BF16 shards and runtime
assets at [revision `5ad04445d2686f525e9fbe5c077e6fa0c7df4200`](https://huggingface.co/ukisai/Swift-1.5-Qwen3.8-27b/tree/5ad04445d2686f525e9fbe5c077e6fa0c7df4200).
The later complete-revision link does not change the actual conversion provenance.

All 1,199 source tensors are accounted for, including 333 vision and 15 MTP tensors.
Eligible linear and embedding weights use 4-bit affine storage; 609 remaining tensors
retain their original BF16 values after the documented layout mapping. All 18 source
shards and runtime assets were verified by SHA-256. No base Qwen or alternate derived
checkpoint weights were substituted.

The saved checkpoint contains three weight shards. The original tokenizer, chat
template, processor/config assets, license and notices are included.
`QUANTIZATION_MANIFEST.json` records the fixed settings and validation results, while
`UPLOAD_MANIFEST.json` records release-file checksums.

## Evaluation

See the [Swift 1.5 source model card](https://huggingface.co/ukisai/Swift-1.5-Qwen3.8-27b#evaluation)
for the source model's evaluations and methodology. Those results were not independently
re-run on this MLX quantization. No broad accuracy or long-context benchmark was run for
this release.

## Validation and use

The validation results below are preserved historical build/component evidence,
not a new full-model Apple run. The approximately 15.83 GB tensor payload
requires additional runtime/cache and OS memory; do not force it onto a
16 GiB Mac or raise system limits.

**Install the included MLX-LM architecture patch before loading this model.**
[`USAGE.md`](USAGE.md) provides the pinned official revision, patch commands and a text
generation example. The source configuration declares
`Qwen3_5ForConditionalGeneration` / `qwen3_5`; the patch preserves that configuration
and the inherited Swift text behavior.

Validation passed on Linux CPU with MLX 0.32.2 and patched MLX-LM 0.32.0: complete
source hashing, strict mapping and reload, finite floating tensors, exact BF16 remainder
preservation, tokenizer/chat-template/processor loading, and a short text-generation
smoke test that returned `Hello from Swift.`.

CPU smoke tests use FP32 floating-point arithmetic with the original packed 4-bit
tensors. This avoids a reproduced accumulation issue in MLX 0.32.2's Linux BF16
quantized-matmul path; checkpoint files and stored BF16 values are unchanged. Follow
the Linux branch in `USAGE.md`.

Apple Silicon checks passed for all 2,379 native tensor headers. Real packed text,
vision and MTP weight samples passed native BF16 Metal execution and matched the FP32
reference within BF16 tolerance. These checks verify native Mac MLX compatibility,
but **full 27B Apple Silicon generation was not tested**.

The vision encoder and an explicit MTP step passed real-weight component checks.
Integrated image/video chat and speculative generation are not implemented in this
patch. Component validation does not establish those end-to-end runtime features.

The `compatibility/` directory retains the MLX-LM patch, reproducible instructions,
source/tensor validation evidence, and the documented runtime limitations. Internal
project names, machine paths and cloud-instance details have been redacted from the
current published copies; older commits remain unchanged.

## License and access

Swift 1.5 is a derivative of [Qwen3.8-27B](https://huggingface.co/Qwen/Qwen3.8-27B)
(Copyright 2026 Alibaba Cloud, [Apache License 2.0](https://huggingface.co/ukisai/Swift-1.5-4bit-MLX/blob/main/LICENSE-APACHE-2.0)). UkisAI's
contribution, including the adapted weights, is licensed under the
**[Swift Open License v1.0](https://huggingface.co/ukisai/Swift-1.5-4bit-MLX/blob/main/LICENSE)**. See [NOTICE](https://huggingface.co/ukisai/Swift-1.5-4bit-MLX/blob/main/NOTICE) for the change notice and
attribution details.

Personal, research, educational, evaluation and commercial use are free for individuals
and organizations with gross annual revenue, including affiliates, of up to US$1,000,000.
Above that threshold, commercial use requires a separate Swift Enterprise License.
Contact [UkisAI](https://ukisai.com/contact) for terms.

Nothing in the Swift Open License limits rights in Qwen3.8-27B itself under Apache 2.0.
The accompanying Apple MLX-LM code has a separate [MIT notice](compatibility/MLX-LM-LICENSE).

## Citation

```bibtex
@misc{swift-1.5-qwen3.8-27b,
  title  = {Swift 1.5 Qwen3.8-27B},
  author = {UkisAI},
  year   = {2026},
  url    = {https://huggingface.co/ukisai/Swift-1.5-Qwen3.8-27b}
}
```

## Acknowledgements

We acknowledge the [NVIDIA Innovation Lab](https://www.nvidia.com/en-us/data-center/innovation-lab/),
[Amazon Web Services](https://aws.amazon.com/), and
[Google Cloud](https://cloud.google.com/) for providing compute credits and
infrastructure support for Swift's development, training, and evaluation.