# GVS5H: Five Qwen3.8-27B Models Match Claude Fable 5 on LiveCodeBench Hard

> Source: <https://github.com/slee-persis/GVS5H>
> Published: 2026-09-12 13:10:54+00:00

**Abstract.** Frontier coding performance is typically bought with larger proprietary models at high cost. We introduce ledger-based zero-shot self-orchestration, a training-free method in which fresh instances of one model decompose problems and coordinate through a shared filesystem holding a plan, notes and current solution. Across nine open and closed-weight models on the 100 latest *hard* LiveCodeBench problems, the method yields gains of up to 23.2 percentage points on pinned backends and offers two routes to frontier-level accuracy. Orchestrated GPT-5.6-Terra reaches 88.0% pass@1 against Fable 5's 90.4% at 19% of the cost, and locally served, open-weight Qwen3.8-27B rises from 69.2% to 92.4%, slightly exceeding Fable 5. Gains are not universal: some models are unchanged or worse. Transcript analysis attributes the gain to decomposition and persistent context. Inference-time organization can approach frontier coding accuracy at a fraction of the cost, or slightly exceed it on self-hostable weights.

Needs [uv](https://docs.astral.sh/uv/) and an API key for the model you want to test.

```
cd codebase/v2-current
export OPENAI_API_KEY=...

LCB_RELEASE=release_v6 \
ESCALATION_CLOUD_MAX_TOKENS=128000 \
ESCALATION_CLOUD_TIMEOUT=7200 \
MULTIAGENT_MODEL=openai:gpt-5.6-terra \
uv run --no-project --python 3.12 --with 'datasets<4' --with numpy --with anthropic \
  python escalation/run_bench.py --engine multiagent --only lcb --lcb 100 --parallel 8
```

- `--engine multiagent` runs the manager;`--engine single` is the one-call baseline.
- Other models: `anthropic:<model>` ,`dashscope:<model>` ,`openrouter:<model>` , each with its own`*_API_KEY` .
- The pass@1 score prints at the end. Results are written to `runs/results.json` , workspaces to`runs/ws/` .

Code is under the [MIT License](/slee-persis/GVS5H/blob/master/LICENSE). The paper, figures and run data are under
[CC BY 4.0](/slee-persis/GVS5H/blob/master/LICENSE-CC-BY-4.0). The LiveCodeBench fork, the benchmark problem statements
and the LaTeX template files keep their own licenses. See [NOTICE.md](/slee-persis/GVS5H/blob/master/NOTICE.md) for
which license covers which path.