The memory feature I'd like to have would need built-in support from anthropic

It'd be essentially

1. Language server support for lookups & keeping track of the code

2. Being able to "pin" memories to functions, classes, properties etc via the language server support/providing this context whenever changes are made in this function/class/properties etc, but not kept, so all following changes outside of that will no longer include this context (basically, changes that touch code with which memories will be done by agents with additional context, and only the results are synced back, not the way to achieve it)

3. Provide a ide integration for this context so you can easily keep track of what's available just by moving the cursor to the point the memory is pinned at

Sadly impossible to achieve via MCP.