Your AI coding agent starts every session blind. Ask Claude Code, Cursor, or Codex a question about your repo and it does the same thing a new hire would: grep , glob , open a file, read 800 lines, open another file, repeat. That discovery loop burns tokens, wastes time, and still misses cross-file relationships that don't show up in a text search. Codebase context tools fix this. They index your code once into something queryable (a knowledge graph, a vector index, or a virtual filesystem)...