π» Gemma4-12B-Coder β safetensors master (full precision) β¨
Composer 2.5 Γ Fable 5 Β· v1 / code edition
This is the full-precision safetensors master for my Gemma 4 12B coding fine-tune β the same model many of
you have been running as GGUF, now in its original weights. π§ π» A focused fine-tune of Gemma 4 12B on
verifiable Python coding data: it reasons in the open (edge cases, complexity, approach) and then writes a
clean, runnable solution.
π― What this repo is for
This repo holds the un-quantized master weights (model.safetensors, bf16). Use it to:
- π§ Roll your own quants β make custom GGUF / MLX / AWQ / GPTQ builds from full precision.
- π§ͺ Fine-tune further β it's a clean base for your own LoRA / continued training.
- π€ Run it in
transformers (needs a recent build with gemma4_unified support).
π Just want to run it? You don't need this repo β grab a ready-made quant from the
GGUF repo β (runs in ~4.5 GB of
VRAM / unified memory in LM Studio, Ollama, llama.cpp, Janβ¦). This master is for builders. π
π Announcements
π v2 is almost here! Initial training of v2 is done and it's in benchmarking + final QA. So many of you
flagged the agentic behavior β so this round I significantly grew the dataset (especially agentic data).
v2 is focused on agentic + coding. Targeting a release this Friday or Saturday (US Pacific). π
π£ Context length is 256K. This master ships with the corrected max_position_embeddings = 262144 (256K) β the
well-known upstream Gemma 4 metadata bug (config.json once said 131072) is already fixed here, so anything you
quantize/convert from these weights inherits the full 256K. π Thanks to the community member who spotted it!
π€ Run it in transformers
π§ Thinking mode: it thinks in Gemma's native thought channel before answering (keep enable_thinking=true,
the default chat template handles it). Recommended sampling: temp 1.0, top_p 0.95, top_k 64; for coding you can
also go greedy (temp 0) for more deterministic solutions. Needs a recent transformers that knows the
gemma4_unified architecture.
π¦ Ready-made GGUF quants
All from the GGUF repo:
β οΈ GGUF needs a recent llama.cpp β this is the gemma4_unified architecture, older builds won't load it.
β‘ Optional: free speed with MTP (lossless)
There's a tiny Gemma 4 MTP draft model in my main reasoning repo β
MTP/ folder. It's the
stock Gemma 4 drafter, so it pairs with any Gemma 4 12B quant β including these coder quants β for
lossless speculative decoding (byte-for-byte identical output, just faster). Because it's trained on base Gemma 4,
the hit-rate on this fine-tune is a bit lower than on vanilla Gemma 4, but it's free and has no downside. Add three
flags (--model-draft, --spec-type draft-mtp, --n-gpu-layers-draft); see the
main repo for the full command. ποΈ
π Training data (the interesting part π³)
A distillation of two complementary chain-of-thought sources over verifiable Python coding tasks
(algorithmic / function-level problems with deterministic tests):
- π₯ Main β Composer 2.5 real CoT. Genuine model-authored reasoning traces; each solution was run against the
task's tests and only passing ones were kept. The reasoning you learn from leads to code that actually works.
- π₯ Aux β Fable 5 redo. The problems where Composer 2.5 got it wrong, handed to Fable 5 to re-derive a fresh,
self-consistent CoT and a correct solution β again gated on passing the tests. Recovers the hard cases the main
teacher missed. These are synthetic (rationalized) CoT and are tagged separately.
Real CoT for solid coverage + synthetic "second-attempt" CoT to patch the failures β all verified by execution
before training. β
β οΈ Good to know
- Reduced refusals: task-focused training with no safety hedging, so it refuses less than the base model. It is
not safety-aligned β add your own guardrails for production. Use responsibly. π
- Specialized for Python / algorithmic coding; general-knowledge facts/numbers should still be double-checked.
- English-centric.
π Base & License
- License: Apache 2.0. Gemma 4 is released by Google under
Apache 2.0 (unlike the older Gemma 1/2/3 terms), so this fine-tune is
Apache 2.0 too β free to use, modify, and redistribute. π
- Base model:
google/gemma-4-12B-it.
- Personal/hobby project β shared as-is, no warranty. Have fun, and happy hacking! πΎβ¨