v2.1 (2026-08-03)
Recalibrated merge. Same training, better weight blending: +1.8 points on
HumanEval-164 over the previous build (74.4 vs 72.6), reproduced across
three independent adapters. If you pulled this model before August 2026,
re-pull for the stronger build.
What it is good at
- It answers. Base Qwen3-4B spends its whole budget inside
<think> on
34% of ordinary prompts and returns nothing. This model answers 34/34 on
the same suite, with 140x less reasoning text and no thinking-mode flag to
manage.
- Agent-shaped reasoning. Trained on genuine multi-step agent sessions,
so plans, tool selection and terminal workflows come out structured
instead of improvised.
- Small enough to keep open. 4B parameters, and the GGUF build is 2.5 GB.
Laptop, old GPU, modest desktop — it runs offline, with your code staying
on your machine.
Evaluation
Measured on identical harnesses, greedy decoding, Q4_K_M builds, thinking
disabled on every row.
Table with columns: Base Qwen3-4B, This model (v2.1) | Base Qwen3-4B | This model (v2.1) |
|---|
| Prompts answered (34-prompt suite) | 27/34 | 34/34 |
| HumanEval-164 | 79.3 | 74.4 |
| Held-out agent-trace loss | 2.846 | 1.876 |
| BFCL simple_python | 95.3 | 92.3 |
| BFCL multiple | 94.5 | 90.0 |
Choosing between this and the base
Take this model for local agent and coding work where you want
structured, reliable answers every time: it fits the agent-session
distribution far better and never silently returns empty.
Take the base model if your workload is maximum-accuracy function
calling in a tool-calling harness, where its few extra points matter more
than reasoning style.
Model details
- Base: Qwen/Qwen3-4B (4B, Apache-2.0)
- Method: QLoRA (nf4, r16, alpha 32) on all-linear targets, completion-only
loss masking, 30% general-instruction replay mix, seed-averaged weights,
merged at scale 0.6 (v2.1 recalibration)
- Data: genuine Claude Fable 5 agent sessions + gpt5.5-terminal
transcripts, deduplicated and decontaminated against the reported benchmarks
- Method report: doi:10.5281/zenodo.21676407
Provenance & licensing
Fine-tuned from Qwen/Qwen3-4B (Apache-2.0). Training data:
Glint-Research/Fable-5-traces
(AGPL-3.0) and
Roman1111111/gpt5.5-terminal
(MIT). Because those traces originate from third-party assistants, the
providers' terms may apply to downstream training and distillation. If you
plan to build on this model commercially, confirm your use aligns with those
terms.
Citation
@misc{aglawe2026agenttrace,
author = {Aglawe, Ankit},
title = {Agent-Trace Fine-Tuning of Small Language Models under Constrained Compute},
year = {2026},
publisher = {Zenodo},
doi = {10.5281/zenodo.21676407},
url = {https://doi.org/10.5281/zenodo.21676407}
}
Acknowledgements
The Qwen team for the base model; Glint-Research and Roman1111111 for the
trace datasets; empero-ai for the recipe this series iterates on.