Model details
Table with columns: Base, This | Base | This |
|---|
| Base model | ornith-ai/Ornith-1.5-35B-A3B | same hybrid GatedDeltaNet + MoE |
| Relation | — | REAP 20% expert prune |
| Experts / layer | 256 | 205 (51 removed) |
| Active / token | 8 | 8 |
| Layers | 40 | 40 |
| On-disk BF16 | ~67 G | ~56 G |
| Library | transformers ≥ 5.8.1 | transformers ≥ 5.8.1 |
| License | MIT | MIT |
Shared expert, vision tower, embeddings, and lm_head are untouched. Router weights renormalized after prune. config.json text_config.num_experts is 205. Architecture: Qwen3_5MoeForConditionalGeneration.
Quickstart
pip install -U "transformers>=5.8.1"
from transformers import AutoModelForImageTextToText, AutoTokenizer
model_id = "oxfrug/Ornith-1.5-35B-A3B-REAP-20pct"
tok = AutoTokenizer.from_pretrained(model_id)
model = AutoModelForImageTextToText.from_pretrained(
model_id, torch_dtype="auto", device_map="auto"
)
messages = [{"role": "user", "content": "Write a one-line Python lambda that squares a number."}]
text = tok.apply_chat_template(messages, tokenize=False, add_generation_prompt=True)
inputs = tok(text, return_tensors="pt").to(model.device)
out = model.generate(**inputs, max_new_tokens=256, temperature=0.6, top_p=0.95)
print(tok.decode(out[0][inputs.input_ids.shape[1]:], skip_special_tokens=True))
vLLM (>=0.19.1), 2× 80GB recommended for long context:
vllm serve oxfrug/Ornith-1.5-35B-A3B-REAP-20pct \
--tensor-parallel-size 2 \
--max-model-len 262144 \
--enable-auto-tool-choice --tool-call-parser qwen3_xml \
--reasoning-parser qwen3 \
--trust-remote-code
Sampling: general temperature=0.6, top_p=0.95, top_k=20. Ornith is a reasoning model — the assistant turn opens with <think>…</think> unless the server splits it into reasoning_content.
Benchmarks
This checkpoint was not re-run on SWE-bench / Terminal-Bench / GPQA. Do not copy the base card’s 79 SWE-bench / 67.8 Terminal-Bench numbers onto this prune.
vs base (this checkpoint)
Table with columns: Base, This | Base | This |
|---|
| Experts / layer | 256 | 205 |
| Disk (BF16) | ~67 G | ~56 G |
| Active params / token | ~3B | ~3B |
Proxy (same recipe, not this checkpoint)
The same REAP 20% recipe on Qwen/Qwen3.5-35B-A3B (0xSero/Qwen3.5-28B, greedy, 0-shot) dropped coding a few points and raised WikiText perplexity. Ornith is a Qwen3.5 hybrid (GatedDeltaNet + MoE); expect a comparable tax, not these exact numbers.
Table with columns: Benchmark, Original Qwen3.5-35B, REAP 20%, Delta| Benchmark | Original Qwen3.5-35B | REAP 20% | Delta |
|---|
| HumanEval pass@1 | 76.2% | 73.2% | −3.0 |
| HumanEval+ pass@1 | 72.0% | 70.1% | −1.9 |
| WikiText-2 PPL (10k tok) | 6.83 | 9.51 | +2.68 |
Source: 0xSero’s card, not a run of oxfrug/Ornith-1.5-35B-A3B-REAP-20pct.
Smoke (this checkpoint)
Greedy, thinking off, 3090 offload. Not a published coding bench.
Table with columns: Prompt, Base, This| Prompt | Base | This |
|---|
square lambda / is_even | match | match |
get_weather with the base card tools= schema | well-formed <tool_call><function=get_weather> / Paris | same |
How it was made
Same mix as 0xSero/Qwen3.5-28B, not Cerebras’ 24k×16k agentic mix:
theblackcat102/evol-codealpaca-v1 × 250
open-r1/Mixture-of-Thoughts code / math / science × 250 each
- 1000 sequences, max length 1024 (3090 VRAM; 0xSero used 4096)
- seed 42,
prune_method=reap, renormalize_router_weights=true
- Layerwise observer (model does not fit in 60 G RAM)
No xlam / SWE-smith traces — extra risk for Ornith’s tool-calling specialists.
Intended use
Local / self-hosted coding and tool-calling with Ornith-1.5 quality, at ~11 GB less disk than the unpruned BF16. Accept a quality tax vs the 35B-A3B base.
Limits
- Expert prune, not a quant and not a fine-tune.
- Shorter calibration sequences (1024 vs 4096) than the Qwen3.5-35B sibling run.
- Hybrid GatedDeltaNet + MoE: REAP only touches MoE experts.
- Do not claim base Ornith-1.5 SWE-bench / Terminal-Bench / GPQA scores for this file.
License
MIT, same as the base. Prune by oxfrug.
Citation
@misc{lasby2025reap,
title = {REAP the Experts: Why Pruning Prevails for One-Shot MoE Compression},
author = {Mike Lasby and Ivan Lazarevich and Nish Sinnadurai and Sean Lie and Yani Ioannou and Vithursan Thangarasa},
year = {2025},
eprint = {2510.13999},
archivePrefix = {arXiv}
}
@misc{ornith_1_5,
title = {{Ornith-1.5}: From Self-Scaffolding to Self-Improvement},
url = {https://ornith.ai/ornith_1_5.html},
author = {{Ornith Team}},
year = {2026}
}