Drafter please? πŸ₯Ί

#2
by Mk2Oracle - opened

I've been waiting for someone to finally do this training because I don't have the GPU power to do it myself. I put my bet on someone doing this given 12B + the quality of opus reasoning would have turned this into a powerful assistant.

Ahem... I'm guessing we can't use gemma's default assistant drafter on this? Not sure how compatibility is when it comes to those things.

Owner

GGUF / llama.cpp: still not really there β€” mainline doesn't recognize the assistant arch yet (unknown model architecture: 'gemma4_assistant'). There's a working experimental fork (reffdev/llama.cpp @ gemma4-mtp, ~70–87% acceptance, up to ~60% faster) and an official WIP PR (#23398), so proper support is coming β€” just not on master today.

vLLM: yes, and you can use Gemma's stock assistant directly. The Gemma 4 MTP spec-decoding PR (#41745) was merged May 6, 2026, and the 12B gemma4_unified_assistant checkpoint is officially supported. Even though this model is fine-tuned, the stock assistant plugs right in and works well (spec decoding is lossless, so output is unchanged). Just point the speculative config at it:

vllm serve <this fine-tuned 12B> \
  --speculative-config '{"method":"mtp","model":"google/gemma-4-12B-it-assistant","num_speculative_tokens":1}'
Owner

Quick update β€” this moved fast: llama.cpp mainline just merged Gemma 4 MTP support today (PR #23398), so GGUF spec-decode now works on master (not just vLLM).
I'll publish the MTP draft GGUF in this repo today β€” so you won't have to set anything up, just download it alongside the model and point llama.cpp at it:

llama-server -m gemma-4-12B-it-<your-quant>.gguf \
  --model-draft MTP/gemma-4-12B-it-MTP-Q8_0.gguf \
  --spec-type draft-mtp --spec-draft-n-max 4 -ngl 999 -fa on

Works with any quant of the main model (just grab a llama.cpp build from today or later). It's a fine-tune so the draft stays lossless and you still get a solid speedup.

Owner

finished!

finished!

got it working, love it ! ty for your work! at Q6 + draft 3 really made this thing fly also what did you do to this model to say "You are testing my patience" 🀣

Wow! The model is working in lightning speed mode!
By the way, is the --temp 1.0 argument for Llama.cpp the optimal one for coding for example? Wouldn't be --temp 0.7 or even --temp 0.5 better? Just asking.

EDIT: disregard, seems Gemma 4 behaves unusually well at higher temperature compared to most coding models

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