---
license: apache-2.0
base_model: Qwen/Qwen3.5-9B
pipeline_tag: image-text-to-text
library_name: transformers
language:
- en
tags:
- qwen3.5
- chat
- creative-writing
- altworld
---

# Altworld Astrea: The New Frontier of Creative Writing

**[Try Astrea →](https://chat.altworld.io)** · **[Get an API key](https://altworld.io/developer)** · **[Read the docs →](https://astrea.altworld.io/docs/)**

Today, we are introducing **Altworld Astrea** — our first openly released
model. Astrea is a compact 9B-parameter model built for one thing: writing
that feels written. It sounds human, it keeps the story straight, and it
beats bigger models at both. You say something, it answers back.

**Altworldbench — overall writing quality.** Elo from 794 blind matchups on
our release pool — both rivals are bigger models built for creative writing:

| | Elo |
|---|---:|
| **Astrea 9B** | **1114** |
| Rocinante-X 12B | 1097 |
| Wayfarer-2 12B | 1045 |

Astrea is available today on [chat.altworld.io](https://chat.altworld.io),
and the full model weights are right here under Apache-2.0, so anyone can
download it and run it locally. An OpenAI-compatible
[API](https://astrea.altworld.io/docs/) is open with simple prepaid pricing.

## What makes Astrea different

### It sounds like a person

Most AI prose gives itself away in the first paragraph: the stock phrases,
the "it wasn't X — it was Y", the em-dash pileups, every reply opening the
same way. We count those tells. Astrea scores **2.5** — roughly two and a
half tells slipping into every thousand words. Every other model we tested
leaves between 8 and 19 per thousand.

### It understands the scene, not just the sentence

Judged blind, story against story, Astrea wins on the things that make
writing actually work: characters whose motivations hold together, a detail
planted early paying off later, the tone you asked for instead of generic
fantasy voice. That depth is what puts it ahead of models three billion
parameters bigger.

### It stays grounded

If the lantern went out, it stays out. If your sword was taken, it doesn't
reappear in your hand two scenes later. That's grounding — remembering what's
true in the story — and creative models are notoriously bad at it. Astrea
keeps **73 of 100** scenes straight. The strongest 12B prose model manages
**44**.

### All of it at 9B

Every rival on our board is both bigger than Astrea *and* purpose-built for
creative writing. Astrea isn't beating generalists — it's beating the
specialists, with three billion fewer parameters. That also means it runs
faster, serves cheaper, and fits on hardware the bigger models can't.

## Altworldbench

We test every release on **Altworldbench**, our own creative-writing
benchmark. Same prompts and settings for every model, every story judged
blind.

**Head-to-head wins** — share of blind matchups Astrea wins:

| | wins |
|---|---:|
| vs Rocinante-X | 52% |
| vs Wayfarer-2 | 65% |

**AI-sounding writing** — lower is better:

| | score |
|---|---:|
| **Astrea 9B** | **2.5** |
| Rocinante-X | 8.1 |
| Wayfarer-2 | 8.3 |
| Muse | 8.8 |
| Violet Lotus | 12.8 |

**Keeps the story straight** — out of 100:

| | score |
|---|---:|
| **Astrea 9B** | **73** |
| Violet Lotus | 68 |
| Muse | 64 |
| Wayfarer-2 | 61 |
| Rocinante-X | 44 |

**Writes the length you ask for** — % of the time:

| | % |
|---|---:|
| **Astrea 9B** | **93** |
| Rocinante-X | 88 |
| Violet Lotus | 83 |
| Wayfarer-2 | 78 |
| Muse | 25 |

All rivals are open 12B creative-writing models.

## See for yourself

Two samples from our test set — unedited, exactly as Astrea wrote them.

> **SCENE:** The rescue party returns with empty stretchers and one boot.
> **ACTION:** I ask the search captain to tell the families myself.

> The captain sets the boot on the table. It is a heavy boot, the kind the
> welders wear, with the steel cap dented in and the laces frayed. The
> stretchers are empty now, returned to the hangar. The rescue party came
> back in four, and one of them did not return.
>
> The families are waiting in the corridor. They have not eaten in days.
> The ration scrip is worthless now that half the station is gone, and the
> spin-section has slowed to a crawl. The air smells of recycled carbon and
> old sweat. You do not speak of the lost. You do not speak of the dead.
>
> The captain turns to you. He does not speak. The boot is on the table. He
> steps back.
>
> You stand. You take the boot. You walk into the corridor. The families
> look at you. There is nothing to say. You set the boot on the floor and
> say, "Your children did not come back."

> **SCENE:** Your partner swore your cargo of walrus ivory to two different
> buyers.
> **ACTION:** I go to the lesser buyer first and offer him the truth and a
> discount.

> The lesser buyer squints at you through a greasy half-door in Uppsala's
> timber shed. The air smells of pine pitch and old fish.
>
> He does not lie. The other party is already buying that ivory. Three
> measures from Helsingjar, not yours. You tell him the truth, offer him a
> discount of two dirhams. He laughs, spits. "The other man has my seal. He
> paid me in hacksilver and a vow over the sacred waters. You offer scraps,
> and I must burn them for luck."
>
> He turns away. The floorboards are wet. Frost lies thin on Lake Mälaren
> beyond the sheds, and the ice does not hold for a barge. The cargo
> remains in the gloom: twenty tusks, the colour of a seal's eye, unsworn
> to you now.

## Availability

- **Talk to Astrea** — chat with it now at
  [chat.altworld.io](https://chat.altworld.io) — no account needed for your
  first turns.
- **Build with the API** — an OpenAI-compatible endpoint at
  `api.altworld.io` — create a key and load credits at
  [altworld.io/developer](https://altworld.io/developer), then
  [start in the docs](https://astrea.altworld.io/docs/).
- **Play Astrea** — Astrea powers the voices of
  [Altworld](https://altworld.io), our life simulator and story sandbox.
- **Download the weights** — this repository: Apache-2.0, BF16 safetensors.

## Build with the API

The Astrea API is **OpenAI-compatible**: if your code already talks to an
OpenAI-style endpoint, point it at our base URL, swap the model name, and it
works — streaming included.

```bash
curl https://api.altworld.io/v1/chat/completions \
  -H "Authorization: Bearer $ASTREA_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "astrea",
    "messages": [{"role": "user", "content": "Open a story in a lighthouse, first person, no cliches."}],
    "stream": true
  }'
```

## Model details

Altworld Astrea (release name Astrea-R8-Chat-9B) was trained on top of the
Qwen3.5-9B base model using multi-round LoRA supervised fine-tuning,
alternating conversational and narrative rounds and checking every round
against Altworldbench. The released checkpoint is the merged BF16 model.

The chat template works bare: no system prompt, no flags, it just answers —
with no visible reasoning block. Explicit thinking is available per-request
with `enable_thinking=True`.

Recommended sampling:

```json
"temperature": 0.8,
"min_p": 0.025,
"repetition_penalty": 1.08
```

Use `temperature 0.2` for factual chat.

## Limitations

- Like any compact model, Astrea can miss nuance or state things confidently
  and wrongly. Verify anything high-stakes independently.
- English dominates its training and evaluation. Other languages will work,
  but with weaker guarantees.
- This release is text-first: the architecture inherits vision support, but
  visual behavior was not part of the release evaluation.
- Astrea is not certified for medical, legal, financial, or other
  high-stakes use.

We plan to keep improving and openly releasing Astrea models — tell us what
to fix. The fastest way to reach us is the Altworld Discord, or open a
Discussion on this repository.

---

## The fine print

**Evaluation protocol.** The pooled Elo is 1113.7 with a 95% bootstrap
interval of 1089.1–1140.9 on a frozen seven-model pool (794 comparisons for
Astrea's entry). The interval overlaps Astrea R8 and Rocinante-X-12B-v1, so
the supported claim is #1 on point estimate and statistical parity with the
top cluster — not a statistically separated win. Pairwise judgments were
made blind by GLM-5p1 and DeepSeek-V4-Flash, with Kimi-K2.6 adjudicating
disagreements; grounding, slop, length/POV/tense, and bare-chat checks
combine deterministic rules with LLM judging. Separately from the narrative
pool: 92.27% pass on 207 held-out bare-chat prompts, 0.00% accidental
fiction, 20/20 on unseen identity paraphrases. One constructed multi-turn
memory probe answered indirectly at temperature 0.2 while fine at 0.8 —
test your own dialogue distributions.

**Running it locally.** Validated in production on vLLM 0.25 (A40, and
2×RTX 3090 with `--tensor-parallel-size 2` — set `NCCL_P2P_DISABLE=1` on
consumer dual-GPU boards):

```bash
vllm serve Altworld/Astrea-R8-Chat-9B \
  --dtype bfloat16 --max-model-len 32768 --gpu-memory-utilization 0.90
```

The base architecture natively supports 262k context; the hybrid
linear-attention layers keep the KV cache small, so serve what your VRAM
affords. With Transformers, load via `AutoProcessor` +
`AutoModelForMultimodalLM` and apply the bundled chat template
(`enable_thinking` defaults off). An MLX-LM smoke run behaved worse than
vLLM at temperature 0.2 despite numerically matched logits — validate your
exact engine. GGUF quants are planned; llama.cpp supports the Qwen3.5
family.

**Lineage and license.** Base model
[Qwen/Qwen3.5-9B](https://huggingface.co/Qwen/Qwen3.5-9B), Apache-2.0; this
derivative is released under the same license — see `NOTICE`. Fine-tuning
preference data used gold responses from MIT-licensed open-weight models
(GLM-5.2, DeepSeek-V4-Flash) with on-policy rejected sides; no closed-model
outputs anywhere. Early-stage data ancestry credits: Athanorlite-DPO
(CC-BY-4.0), jondurbin/gutenberg-dpo-v0.1 (CC-BY-4.0),
nbeerbower/gutenberg2-dpo and gutenberg-moderne-dpo (Apache-2.0),
Pageshift-Entertainment/LongPage, allenai/tulu-3-sft-mixture (ODC-BY,
license-filtered), nothingiisreal/Reddit-Dirty-And-WritingPrompts
(Apache-2.0, SFW file only). Thanks to the Qwen team for the base model.