For the time being, off the top of my head, I'd say:
- Prompt Engineering tips & tricks apply here (like being complete in the relevant context you provide in your question, and the specific task(s) the agent should do like reasoning, modifying one file, or trying to fix a complex task all at once (not recommended)).
- If you already know which files the agent should look into, mention them to save time and potentially context.
- In my personal workflow, I write down lots of atomic TODOs needed to solve a problem. As I write it down, I'll notice assumptions I'm making, or the fact that the TODO could still be decomposed further into (atomic) subtasks.
- It's best to get a feeling yourself for how Qwen handles your repository. I noticed if I don't specify an architecture for development, it'll make quick & dirty fixes. If I don't tell it to remove debug statements, it won't. This is what was meant with "be precise" – Claude Opus might think for you and act in your best interest. Smaller Qwen models will just do what you ask them to, and no more. They have design knowledge, but you have to explicitly ask them to "activate" that part of their knowledge.