For people working with small local models like Qwen 35b what's even more important us that the LLM is good at coding in the language in which the agent harness

For people working with small local models like Qwen 35b what's even more important us that the LLM is good at coding in the language in which the agent harness is written so that it can write skills. I really like pi but had a few instances now where Qwen wasn't able to extend it because it isn't very good at writing typescript. Does that sound familiar to anyone, and did you find any fixes?