Scoping Instruction Files

Use when the user asks how to write, scope, or organize agent instruction files — "what should go in my CLAUDE.md?", "should I split CLAUDE.md into a rules folder?", "how do I scope rules to certain files or directories?", "CLAUDE.md or AGENTS.md?", "why does the agent ignore my rules?", "one big file or many small ones?" Walks through the instruction-budget ceiling and the would-the-agent-err-without-this-line test for every candidate line, precedence and nesting schemes (closest-file-wins vs concatenated hierarchies), glob-conditional loading (Amp @-mention globs, Cursor description/globs/alwaysApply), and single-file-vs-modular tradeoffs for team alignment. Not for run…