# AltSlate Labs: certo

> AltSlate Labs' research-preview decision model on Qwen3-4B. It reads a state and a list of described options and returns a calibrated probability per option for choice, score and yes/no (noul) questions, read by a small head at the last prompt token.

- Page: https://systemonemodels.ai/altslate-labs/certo
- API: https://api.systemonemodels.ai/v1/models/altslate-labs/certo
- Download: `pip install systemonemodels && systemone pull altslate-labs/certo`

## Facts

| | |
|---|---|
| Maker | AltSlate Labs (https://systemonemodels.ai/altslate-labs) |
| Decides | choice, score, noul |
| Architecture | certo |
| Base model | qwen/qwen3-4b |
| Parameters | 4.0B |
| Licence | apache-2.0 |
| Availability | Open weights |
| Released | 2026-09-28 |
| Latest version | 2026.09 |

## Model card

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# Certo Unified 4B

AltSlate Labs' research-preview decision model on Qwen3-4B. It reads a state and a list of described options and returns a calibrated probability per option for choice, score and yes/no (noul) questions, read by a small head at the last prompt token.

A research preview. On its fast path a small head reads the last prompt token; an optional reasoning path writes a short rationale first, which is not one pass. On AltSlate's own held-out evaluations choice reaches 0.93 to 0.97 and noul 0.88 to 0.92, with temperatures fitted on a separate split; score on an unseen rubric is about 0.46. On the third-party JevBench public items the maker's own run gives 0.71 with ECE 0.22. head.pt is a PyTorch pickle. Family members: certo-decision-model v1 (MIT, an encoder trained on Certo's synthetic world), certo-decision-v2.1 (MIT) and certo-r1-qwen3-4b (Apache-2.0).

## 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 probability

## At a glance

| | |
|---|---|
| Parameters | 4B |
| Base model | `Qwen/Qwen3-4B` |
| Maker | AltSlate Labs |
| Released | 2026-09-28 |
| License | apache-2.0 |

## Get the weights

```bash
pip install systemonemodels
systemone pull altslate-labs/certo
```

The files are served from the maker's Hugging Face repository, [`altslate/certo-unified-4b`](https://huggingface.co/altslate/certo-unified-4b), and verified against the checksums recorded here.

## Read more

- [Model card](https://huggingface.co/altslate/certo-unified-4b)
- [certo-decision-model (v1)](https://huggingface.co/altslate/certo-decision-model)
- [certo-r1-qwen3-4b](https://huggingface.co/altslate/certo-r1-qwen3-4b)
- [Code](https://github.com/AltSlate-Labs/certo)

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

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