Why are engineers so obstinate about this stuff? You really need a GUI built for you in order to do this? You can't take the time to just type up this instruction to the LLM? Do you realize that's possible? You can just write instructions "Don't modify XYZ.ts file under any circumstances". Not to mention all the tools have simple hotkeys to dismiss changes for an entire file with the press of a button if you really want to ignore changes to a file or whatever. In Cursor you can literally select a block of text and press a hotkey to "highlight" that code to the LLM in the chat, and you could absolutely tell it "READ BUT DON'T TOUCH THIS CODE" or something, directly tied to specific lines of code, literally the feature you are describing. BUT, you have to work with the LLM and tooling, it's not just going to be a button for you or something.
You can also literally do exactly what you said with "going a step further".
Open Claude Code, run `/init`. Download Superwhisper, open a new file at project root called BRAIN_DUMP.md, put your cursor in the file, activate Superwhisper, talk in stream of consciousness-style about all the parts of the code and your own confidence level, with any details you want to include. Go to your LLM chat, tell it to "Read file @BRAIN_DUMP.md" and organize all the contents into your own new file CODE_CONFIDENCE.md. Tell it to list the parts of the code base and give it's best assessment of the developer's confidence in that part of the code, given the details and tone in the brain dump for each part. Delete the brain dump file if you want. Now you literally have what you asked for, an "index" of sorts for your LLM that tells it the parts of the codebase and developer confidence/stability/etc. Now you can just refer to that file in your project prompting.
Please, everyone, for the love of god, just start prompting. Instead of posting on hacker news or reddit about your skepticism, literally talk to the LLM about it and ask it questions, it can help you work through almost any of this stuff people rant about.