With Claude the context window is quite small. But with adding too much context it often seems to get worse. If the context is not carefully narrowly picked and too unrelated, the LLMs often start to do unrelated things to what you've asked.
At some point it's not really worth anymore creating the perfect prompt, just code it yourself. Also saves the time to carefully review the AI generated code.
There's probably a sweet spot. Same with people. Too much context (especially unnecessary context) can be confusing/distracting, as well as being too vague (as it leaves room for multiple interpretations). But generally, I find the more refined and explicit you are, the better.