PSA: Gemma 4 12B is NOT completely broken for coding and tool calling, you need a special chat template

This is a PSA for people like me who tried it and hit the wall with tool calls failing left and right, so much so that harnesses like OpenCode just didn't work: There is a fix for that. You need to pass a better chat template file, [which is available](https://gist.github.com/jscott3201/ad69c4ffbd79f18b11a0f6a94c94fadf) (I did not write it). [See also this comment.](https://www.reddit.com/r/LocalLLaMA/comments/1twmw4o/comment/oppmvdg/) To actually use it with llama.cpp, **first compile llama.cpp from source,** then download the chat template file I linked above, then try this (8 bit quant in this case): ./build/bin/llama-server -hf unsloth/gemma-4-12b-it-GGUF:UD-Q8_K_XL --host 127.0.0.1 --port 8899 --jinja --chat-template-file ./custom-pub-chat-template-gemma4.jinja I'm not saying the results are great, or good, or better or worse than Qwen 3 9B or any other model! But with this setting, the tool calling bugs go away and you can genuinely evaluate its capabilities in opencode. So, please do that before forming a judgement of the model's coding ability. But once you've done that, judge away 😀 I'm posting because I see so many "I can't code with Gemma 4 12B, tool calls never work" comments that it's tough to cut through the noise when discussing the model. Thanks to u/HVACcontrolsGuru for bringing the solution to my attention. I hope I'm not stealing their thunder, just thought it was time to call more eyeballs to this.