Claude Code now has built-in LSP (Language Server Protocol) support, enabling compiler-accurate code navigation instead of plain-text grep searches. LSP gives AI coding agents the same structural code intelligence an IDE provides: precise go-to-definition, find-all-references, type diagnostics, and safe renames. Benchmarks on the vuejs/core repo (~149K lines of TypeScript) show LSP reduces token usage by 31-33% and cost by 3-14% compared to grep, while also eliminating missed references that grep-only runs produced on Sonnet 4.6. Setup requires three commands: install the language server binary, install the matching Claude Code plugin, and reload. Trade-offs include memory overhead (rust-analyzer can use several GB), cold-start indexing time on large repos, and per-language configuration requirements.
