I'm kinda confused about why this even is something that we need an extra feature for when it's basically already built in to the agentic development feature. I just keep a folder of md files and I add whatever one is relevant when it's relevant. It's kinda straight forward to do...
Just like you I don't edit much in these files on my own. Mostly just ask the model to update an md file whenever I think we've figured out something new, so the learning sticks. I have files for test writing, backend route writing, db migration writing, frontend component writing etc. Whenever a section gets too big to live in agents.md it gets it's own file.
It’s a formalisation of the method, and it’s in your global ~/.claude and also per project.
I have mine in a GitHub template so I can even use them in Claude Code for the web. And synchronise them across my various machine (which is about 6 machines atm).
This helps me get an idea of what we’re doing. I get pushback and have to be clear and Opus is good at asking questions.
Then I get it to write a set of documents for Claude Code describing the vision, the solution, the technical choices, the testing plan, the validation approach, how to share with colleagues, future ideas and a table of contents.