Install a greppable code index so agents locate files/symbols without rescanning the project every session — generates an index.sh (dirs/files/symbols with file:line, per repo or workspace member), wires .gitignore + CLAUDE.md, offers a SessionStart refresh hook, then runs a validation pipeline (syntax, edge-case sandbox, measured recall check, staleness detection, optional A/B benchmark). Use whenever the user wants to set up code indexing, complains that the agent re-scans/re-explores the whole project to find things, asks to make agent search faster/cheaper, or mentions a project index, code map, symbol index, or ctags-like setup for agents.
