prose-rewriter-4b-v2.2

A paragraph-level prose rewriter: it takes prose written by a large model and re-renders it to be more human, preserving the semantics it was given.

Qwen/Qwen3-4B-Base with a rank-32 LoRA merged in at strength 1.20.

A third less repetition. Every training target that repeats itself -- the same sentence twice, a phrase said again, three sentences opening on the same words, happy, happy -- is now rejected, so the pool only ever shows the model the repetition going away. Rewrites that repeat themselves fall from 13.5% to 8.7%.

Less unsupported content, less slop vocabulary, at the same strength as v2.1. See Evaluation.

Variants

The quants carry the chat template and stop on <|im_end|>, and the adapted output head is kept separate from the token embeddings, stored at Q8_0.

Prompt format

<|im_start|>source
{paragraph}<|im_end|>
<|im_start|>rewrite

The chat template in this repo builds exactly that string, byte for byte, from one message:

messages = [{"role": "source", "content": paragraph}]
tok.apply_chat_template(messages, tokenize=False, add_generation_prompt=True)

It is not a chat model. Every message is rendered as the source paragraph, so a runtime that probes the template with a user message still gets a valid prompt. Send one message per call.

Serving recipe

Sampled at temperature=0.9, top_p=0.9. However, temperature 0.9 hallucinates harder because this release edits harder than v2. It's recommended you use 0.8-0.85 instead.

import torch
from transformers import AutoModelForCausalLM, AutoTokenizer

repo = "chartreuse-verte/prose-rewriter-4b-v2.2"
tok = AutoTokenizer.from_pretrained(repo)
model = AutoModelForCausalLM.from_pretrained(repo, dtype=torch.bfloat16, device_map="cuda").eval()

def rewrite(paragraph):
    text = tok.apply_chat_template(
        [{"role": "source", "content": paragraph}],
        tokenize=False, add_generation_prompt=True,
    )
    ids = tok(text, return_tensors="pt", add_special_tokens=False).input_ids.to(model.device)
    out = model.generate(ids, max_new_tokens=512, do_sample=True, temperature=0.9, top_p=0.9)
    return tok.decode(out[0, ids.shape[1]:], skip_special_tokens=True).strip()

Same thing under llama.cpp. The role is source, which no chat API models, so build the string yourself; <|im_end|> stops it:

llama-cli -m GGUF/prose-rewriter-4b-v2.2-Q8_0.gguf -no-cnv -n 512 --temp 0.9 --top-p 0.9 \
  -p '<|im_start|>source
{paragraph}<|im_end|>
<|im_start|>rewrite
'

Input length

The training pool's median input is 37 words and 80% of it is under 70, so serve it on anything from a full sentence up.

The practical floor is about 15 words. Below it the failure mode is padding, cutting and fabrication rather than gibberish. Below 80 bytes, pass the text through unchanged.

Evaluation

Both releases measured as they ship, baked at strength 1.20, on 365 held-out paragraphs of LLM-written prose that neither model saw in training, at temperature=0.9, top_p=0.95, three swipes each. 1,095 generations an arm.

Pronoun invention numbers for this release, on 400 single-gender roleplay paragraphs:

Paired over the 400 inputs, none of these separates.

Repetition on the 365 paragraphs -- a rewrite that repeats a sentence, a phrase, or a sentence opening:

Paired over the 365 inputs, any repetition falls (t = -3.6), repeated phrases fall (t = -2.8) and anaphora falls (t = -2.5).

Structural, on the same paragraphs:

Paired over the 365 inputs, only sentence count moved separates (t = +2.2). Over the 303 inputs of 51-90 words, no column does.

Unsupported content -- a sentence in the rewrite the input does not entail, scored by NLI with the input alone as the premise:

Paired over the 365 inputs, the unsupported rate falls (t = -2.3); coverage does not move.

The register numbers on the same paragraphs, against the input:

Paired over all 365 inputs, lexicon density falls (t = -2.6). Banned constructions and purple do not separate.

Dialogue: the number of spoken lines changes on 1.6% of rewrites against v2.1's 0.8% (t = +1.7, does not separate), and of the rewrites whose input carried quoted speech, 1.0% lost the quotes entirely -- the same for both.

Markup round-trip on 365 tagged paragraphs -- every marker handed back in order, with the same counts: 79.5% for v2.1, 78.1% here.

A note on strength

Every number above is measured at the strength the release is baked at, which is not the same as measuring the adapter. LoRA strength is spent at merge time (W + (B @ A) * 2.40 here), and the metrics move with it: read at the adapter's natural 1.0 this same checkpoint is a materially different artifact.

Both releases ship at 1.20, so every difference above is the training pool and not the strength. 1.20 is where banned constructions bottomed out on the strength sweep: 1.15 carries a third more of them.

Training

Corrupt forward, train backward. The human paragraph is the target; an on-policy LLM manufactures the input by slop-ifying it.

The target side is human prose: published contemporary literary fiction, r/WritingPrompts (Mollymo/Human-to-AI-writing), AO3 (midwestern-simulation-active/ao3_random_subset), a scrape of bluemoonroleplaying.com -- the only human writing in the pool already in the deployment's own register -- and a sliver of fanfiction.net (atom-in-the-universe/fanfics-10k-10k).

The input side is manufactured from those targets, weighted and share-capped so that no single generator's tics dominate:

Pairs pass invariant gates before they reach the GPU: POV, tense, who is in the scene, the gender of who is in the scene, the number of spoken lines, grammatical correctness on the target side, no repetition on the target side, content recall stratified by target length, and NLI entailment both ways. Two further screens shape what reaches training -- a floor on how much a pair actually changes, and a floor on the sentence-length variety of the target, applied at a higher threshold for long paragraphs than short ones.

Loss on the target paragraph only. Everything before rewrite is masked.

The merge

Merged at strength 1.20. Rank 32 with alpha 64 is a LoRA scaling of 2.0, so the effective scaling is 2.40: W + (B @ A) * 2.40. Merged in float32, stored bfloat16.

lm_head is adapted, and Qwen3-4B-Base ties lm_head.weight to embed_tokens.weight. This checkpoint is untied: the merged output head is stored separately and the input embeddings are bit-identical to the base model's, which is what training assumed. config.json says tie_word_embeddings: false and it means it. Do not re-tie it, and if you convert to another format, check that the head survived.

Limitations

• Not an instruct model. It has one job and one prompt. There is nothing to ask it.
• Works on fictional prose only. May not work on technical documentation.
• One paragraph per call. Longer input degrades; split it.
• Still invents people occasionally. A phantom pronoun appears in 0.8% of rewrites. Check the output when the cast matters.
• Truncates. It drops below 0.75x the input's length on 21.4% of paragraphs. Usually that is the slop going; check the output when length matters.
• Still repeats itself. 8.7% of rewrites repeat a sentence, a phrase or a sentence opening the input did not. Check the output for loops.
• Will not pass AI detectors. Pangram and such will still know because this model preserves word choices and certain sentence structures.
• English only, narrative register (third and first person fiction, dialogue with quoted speech).
• Short input pads, cuts and invents. The floor is about 15 words. See Input length.
• Repeats a noun sooner than an LLM would. Human prose reuses a plain noun where generated prose uses a synonym, and this model has learned that habit.

License

The weights in this repository are released under the GNU Affero General Public License, version 3. The full text is in LICENSE.

This is a derivative of Qwen/Qwen3-4B-Base, which is licensed under Apache License 2.0. That license is preserved and its terms continue to apply to the base weights this model was built from; the AGPL covers the combined work as distributed here. Apache-2.0 is one-way compatible with AGPLv3, which is what makes this combination possible.

If you run a modified version of this model as a network service, AGPL section 13 requires you to offer the corresponding source of your modifications to its users.