CLI tools are better about this IME. I use one called opencode which is very transparent about their prompts. They vendor the Anthropic prompts from CC; you can

CLI tools are better about this IME. I use one called opencode which is very transparent about their prompts. They vendor the Anthropic prompts from CC; you can just snag them and tweak to your liking. Unfortunately the “user instructions” a lot of online chat interfaces provide is often deemphasized in the system prompt