GVS5H Framework Lets Five Qwen Models Match Claude Fable 5 on Coding

Original title: Five Qwen3.8-27B models match Fable 5 Using GVS5H Harness
78AI Score
Executive Summary

GVS5H introduces a ledger-based zero-shot self-orchestration method where multiple model instances coordinate via a shared filesystem. Experiments show five Qwen3.8-27B instances match Claude Fable 5's performance on hard LiveCodeBench problems without training, offering a low-cost path to frontier coding capabilities.

Full Report

Contents3 sections

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

GVS5H: Gorilla vs. 5 Humans

Results

Accuracy on LiveCodeBench, single call versus with manager, for seven models against Claude Fable 5's single-call score

Opus 5 ran on an earlier version of the scaffold, in a single pass served through OpenRouter rather than five on a pinned backend.

Average cost per task against accuracy, single call versus with manager, on a log-scale cost axis

What one pass costs — LCB-100, 5 passes, single call vs manager, against Fable 5

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 eleven open and closed-weight models on the 100 latest hard LiveCodeBench problems, the method yields gains of up to 25.6 percentage points on pinned backends and offers two routes to frontier-level accuracy. Orchestrated Qwen3.8 Flash Next reaches 93.0% pass@1 against Fable 5's 90.4% at 9% of the cost, and locally served, open-weight Qwen3.8-27B rises from 66.8% to 92.4%. 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.

— the paper

Running the code

Needs uv and an API key for the model you want to test.

BASH
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/.