---
license: apache-2.0
base_model: Qwen/Qwen3-8B-Base
tags:
- code
- livecodebench
- sft
- lora-merged
- nothink
library_name: transformers
---

# code-nothink-q8b-20260908

Formerly `Qwen3-8B-Base-code-v4-nothink` (HF redirect).

**Arm ID:** `Q8B-NOTHINK`  
**Run ID:** `t30b2507-q8b-nothink-v4-tail151643`

Merged full bf16 weights used for the official DEV256 NoThink evaluation. Tokenizer files in this repo are the **eval-caliber** bundle (`qwen3-v4-tail151643`); they overlay any tokenizer files that were present in the merge directory (the merge tree's `tokenizer.json` was a different, larger file).

**Exploratory result (2 eval seeds), not a preregistered confirmatory claim.**

## Base model

- Hugging Face: [`Qwen/Qwen3-8B-Base`](https://huggingface.co/Qwen/Qwen3-8B-Base)
- Revision: `49e3418fbbbca6ecbdf9608b4d22e5a407081db4`

## Training

- Method: LoRA r64 / α128 on seven projections (`q_proj`, `k_proj`, `v_proj`, `o_proj`, `gate_proj`, `up_proj`, `down_proj`), then merged into full-model bf16 safetensors
- Data: NoThink code SFT (paired V4, physical 2-epoch concat)
- Endpoint (score): **step 142**, **9,455,736** assistant tokens — endpoint-as-score, no checkpoint picking
- Train seed 42; LR `1e-4`; context 8192; AdamW; cosine by assistant-token dose
- Host: local GPU 3 (retrain after mathbox3 host loss); eval tokenizer renderer `qwen3-v4-tail151643`

## Evaluation

- Suite: official LiveCodeBench **DEV256**
- Mode **NoThink**, `max_model_len` **8192**, vLLM **0.28.0**; do not prefill `<think>`
- Metric: sandbox pass@1 = passed / 256
- Seed 12345 used the same merged weights, tokenizer, and vLLM command as seed 3407 except `--seed` and the serve port. Results: `/workspace/code-sft-runs/rstar-eval/official-dev256-seeds/seed12345/`

| seed | arm | arm cap | Base | Base cap | McNemar arm_only / base_only | p |
|---|---|---|---|---|---|---|
| 3407 | 70/256 (27.3%) | 78 | 59/256 (23.0%) | 21 | 25 / 14 | 0.108 |
| 12345 | 84/256 (32.8%) | 75 | 57/256 (22.3%) | 23 | 37 / 10 | 9.8e-05 |
| pooled 512 | — | — | — | — | 62 / 24 | 5.1e-05 |

Mean: arm **77.0 (30.1%)** vs Base **58.0 (22.7%)**, Δ ≈ **+19**.

Arm pass@1 moves a lot across seeds (70 vs 84); Base is stable (57–59). The two-seed pooled paired difference is significant (**p = 5.1e-05**). Still exploratory (2 seeds, not preregistered).

## Provenance note

The same identity (seed 42, 9,455,736 assistant tokens, lr 1e-4, LoRA r64/α128) was previously trained once on another machine and scored 76/256 vs Base 57/256 (McNemar p=0.0019). That host went down and the weights plus eval cache were lost. This repository is the local GPU 3 retrain. The two-run difference (arm −6, Base +2) is single-seed cross-machine noise. This result is a single-seed exploratory outcome, not a confirmatory claim.

## Inference notes

- Use **this repository's** tokenizer and `chat_template.jinja`.
- NoThink: do not prefill `<think>`; if the template accepts `enable_thinking`, keep it false.
- Stop token ids: **151643** (`<|endoftext|>`) and **151645** (`<|im_end|>`).
- Eval sampling used temperature 0.7, top_p 0.8, top_k 20.

## Weight checksum

- `model.safetensors` (16,381,517,208 bytes): `sha256:fdde336f8a504ce0dae4537b0955bbe660e1072ec093e43cce548e5654958a94`

`OFFICIAL_MERGE_RECEIPT.json` is included for merge provenance. LoRA adapter checkpoints are **not** in this repo.