I pretty clearly say I still use CLAUDE.md/AGENTS.md

I've just been trimming down to the recommended < 100 lines and I keep only super high level info in there and allow the agents to figure things out by reading the code.

I wouldn't use a blog post from Nov 2025 be my guiding light.

Anthropic over the past few months have said they've cut their system prompts 80%. These are current best practices. The models are good enough and can figure things out on their own BETTER than you can present the info in markdown files and "decision" documents.