---
title: "Models, downloads, and storage"
description: "Know what the CLI downloads, where it stores the files, and how much free space the first run needs."
canonical: "https://www.fermionresearch.com/docs/models-downloads/"
source: "Fermion Research"
---

Docs / Getting started

# Models, downloads, and storage

Know what the CLI downloads, where it stores the files, and how much free space the first run needs.

## Released models

| Model | Runnable container | Coded transport | Primary use |
| --- | --- | --- | --- |
| Neutrino-1 8B | 3.88 GB | 2.56 GB | Default general model and tool caller |
| Neutrino-1 0.6B | 328 MB | 238 MB | Small model and canonical speculative draft |
| Neutrino-1 0.6B-Chat | 328 MB | 238 MB | Small conversational model |

## Speech models

The speech commands default to `FermionResearch/Phonon-1`. Every speech command takes `--model` with a repository id, a short alias, or a local model directory.

| Model | Download | On disk | Aliases |
| --- | --- | --- | --- |
| [Phonon-1](https://huggingface.co/FermionResearch/Phonon-1) | 415 MB | 455 MB | phonon, phonon-1, stt, asr |
| [Phonon-1-Big](https://huggingface.co/FermionResearch/Phonon-1-Big) | 581 MB | 822 MB | phonon-1-big, big |
| [Phonon-1-Micro](https://huggingface.co/FermionResearch/Phonon-1-Micro) | 285 MB | 331 MB | phonon-1-micro, micro |

```text
fermion transcribe clip.wav --model micro
fermion serve --model FermionResearch/Phonon-1-Micro
```

A speech model downloads as a single verified archive and unpacks under `~/.cache/fermion/speech`; the archive itself sits in the Hugging Face hub cache. `FERMION_CACHE_DIR` and `HF_HOME` move both.

## The first-run download plan

The CLI downloads only the files required to run the selected model. GGUF and MLX files are not fetched by default.

| Platform | Downloaded | Steady state | Peak free space |
| --- | --- | --- | --- |
| Apple Silicon | 2.56 GB transport | about 3.9 GB | about 6.5 GB |
| Other platforms | 3.88 GB container | about 3.9 GB | about 4 GB |
| 0.6B models | 238 MB transport or 328 MB container | 328 MB | under 600 MB |

On Apple Silicon, the verified transport is deleted after expansion. Set `FERMION_KEEP_TRANSPORT=1` if you want to keep it. Set `FERMION_DOWNLOAD_ALL=1` only when you intentionally want the whole repository.

## Move the model cache

Models use the standard Hugging Face cache under `~/.cache/huggingface/hub`. Move all Hugging Face data with `HF_HOME`, or move only Fermion model downloads with `FERMION_CACHE_DIR`.

```text
export HF_HOME=/big/disk/hf
# or
export FERMION_CACHE_DIR=/big/disk/fermion

fermion chat
```

A small `~/.cache/fermion` directory may also hold generated Transformers configuration directories.

## Disk-space checks and interrupted downloads

Before downloading weights, fermion checks the real cache volume against the model manifest. If the volume is too small, it stops before the transfer and prints the cache path, required bytes, available bytes, and the two cache variables above.

If a download or local expansion is interrupted, run `fermion info`. The command detects incomplete structure and hash mismatches and exits non-zero for automation.

Source: [https://www.fermionresearch.com/docs/models-downloads/](https://www.fermionresearch.com/docs/models-downloads/)