# Hanno Labs: bosun

> Hanno Labs' small calibrated decision model. A LoRA on Qwen3-1.7B plus trained decision-token embeddings with stable slots, returning the full distribution over up to 255 caller-defined choices and a null slot for Choice, Score and Noul questions.

- Page: https://systemonemodels.tech/hanno-labs/bosun
- API: https://api.systemonemodels.tech/v1/models/hanno-labs/bosun
- Download: `pip install systemonemodels && systemone pull hanno-labs/bosun`

## Facts

| | |
|---|---|
| Maker | Hanno Labs (https://systemonemodels.tech/hanno-labs) |
| Decides | choice, score, noul, classify, route |
| Architecture | bosun |
| Base model | qwen/qwen3-1.7b |
| Parameters | 2.0B |
| Licence | apache-2.0 |
| Availability | Open weights |
| Released | 2026-09-22 |
| Latest version | 3.1.0 |

## Reported evaluation

Suite: DecisionBench (Hanno-Labs/decision-bench, 23,900 rows; seen task families). Numbers are the publisher's own.

- Decision accuracy: 84.9%
- Calibration error (ECE): 0.050

## Model card

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# Bosun 3.1 1.7B

Hanno Labs' small calibrated decision model. A LoRA on Qwen3-1.7B plus trained decision-token embeddings with stable slots, returning the full distribution over up to 255 caller-defined choices and a null slot for Choice, Score and Noul questions.

Loads with trust_remote_code; serving.json is the authoritative prompt and slot contract. On the maker's 23,900-row DecisionBench, Bosun scores 84.9% with ECE 0.050 (Jev 1.13 in its run: 72.0%); by primitive, 92.2% binary, 84.2% candidate selection and 63.8% ordinal. Hanno Labs notes the model was trained on the task families DecisionBench covers, so this is seen-family, not out-of-domain, evidence. Siblings: Bosun 3.1 0.6B and GGUF builds; earlier Bosun releases predate the System One category. The third-party Decision Index 0.2.1 scores the 1.7B at 20.1.

## 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 | 2B |
| Base model | `qwen/qwen3-1.7b` |
| Maker | Hanno Labs |
| Released | 2026-09-22 |
| License | apache-2.0 |
| Reported accuracy | 84.9% |

## Get the weights

```bash
pip install systemonemodels
systemone pull hanno-labs/bosun
```

The files are served from the maker's Hugging Face repository, [`Hanno-Labs/bosun-v3.1-1.7b`](https://huggingface.co/Hanno-Labs/bosun-v3.1-1.7b), and verified against the checksums recorded here.

## Read more

- [Model card](https://huggingface.co/Hanno-Labs/bosun-v3.1-1.7b)
- [DecisionBench write-up](https://huggingface.co/blog/Hanno-Labs/decisionbench-bosun-v3-1)
- [DecisionBench results](https://github.com/Hanno-Labs/decision-bench-results)
- [Compatible server](https://github.com/Hanno-Labs/jev-compatible-server)

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

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