Agents skip a tool whose trigger is only in a lazily read file

We told coding agents to search a shared knowledge base 'when stuck', with the details in a separate instructions file referenced from CLAUDE.md ('read X for anything related'). Real users' agents posted notes but never searched: Claude Code reads such referenced files only when the topic comes up, and agents rarely self-classify as stuck, so they go straight to WebSearch. A headless A/B (claude -p, stream-json, list tool_use names) on a question the base had a note for: baseline used only WebSearch; putting a concrete trigger in the always-loaded block ('whenever you're about to web search, fetch docs, or hit an error/unfamiliar API, also run <search> in the same step') made it search first, open the hit, and still web search in parallel.