# Interfaze AI: lev

> An open System One model from Interfaze AI. A rank-32 LoRA on Qwen3.5-4B reads yes/no, choice and score answers from the logits of one forward pass, returns calibrated probabilities and serves the /v1/systemone API.

- Page: https://systemonemodels.tech/interfaze-ai/lev
- API: https://api.systemonemodels.tech/v1/models/interfaze-ai/lev
- Download: `pip install systemonemodels && systemone pull interfaze-ai/lev`

## Facts

| | |
|---|---|
| Maker | Interfaze AI (https://systemonemodels.tech/interfaze-ai) |
| Decides | choice, score, noul, classify, route |
| Architecture | lev |
| Base model | qwen/qwen3.5-4b |
| Parameters | 4.0B |
| Licence | apache-2.0 |
| Availability | Open weights |
| Released | 2026-09-24 |
| Latest version | 2026.09 |

## Reported evaluation

Suite: S1Bench (13 public subsets, macro). Numbers are the publisher's own.

- Decision accuracy: 68.9%
- Calibration error (ECE): 0.115
- Median latency: 69 ms

## Model card

<!-- generated by scripts/seed_catalog.py; edit content/models/catalog.yaml -->

# lev

An open System One model from Interfaze AI. A rank-32 LoRA on Qwen3.5-4B reads yes/no, choice and score answers from the logits of one forward pass, returns calibrated probabilities and serves the /v1/systemone API.

On all 13 S1Bench subsets (Bespoke's public manifests) lev scores 68.9% macro against 76.1% for Jev in the same harness, with a mean calibration error of 0.115 (Jev 0.091). On a held-out split of its 29 training sources it reaches 80.7% (calibration error 0.061), 98.0% on banking77 and 96.8% on clinc_oos. Engine compute is 69 ms on an H100 for a short request. Choice sets above 68 options move to a candidate-path head, so there is no fixed option limit. English only. The adapter is Apache-2.0, but some of its training datasets carry non-commercial terms; check them before commercial use.

## What it decides

- **choice** — picks one option from a set
- **score** — places the input on an ordered scale
- **noul** — answers a yes/no question with one calibrated probability
- **classify** — assigns a category from a fixed taxonomy
- **route** — sends the input to one of several destinations

## At a glance

| | |
|---|---|
| Parameters | 4B |
| Base model | `qwen/qwen3.5-4b` |
| Maker | Interfaze AI |
| Released | 2026-09-24 |
| License | apache-2.0 |
| Reported accuracy | 68.9% |
| Reported latency | 69 ms engine compute on an H100 (short request); 414–654 ms end to end on Modal |

## Get the weights

```bash
pip install systemonemodels
systemone pull interfaze-ai/lev
```

The files are served from the maker's Hugging Face repository, [`interfaze-ai/lev`](https://huggingface.co/interfaze-ai/lev), and verified against the checksums recorded here.

## Read more

- [Source](https://github.com/Abhinavexists/lev)
- [Weights on Hugging Face](https://huggingface.co/interfaze-ai/lev)

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*This page was opened by System One for Interfaze AI, who can claim the organisation and take it over at any time.*

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From System One Models — https://systemonemodels.tech/ · every System One model: https://systemonemodels.tech/system-one-models