# Graph Indexer FAQ > Answers about Graph Indexer: what it is, how it differs from grep, privacy, cost, speed, languages, monorepos, agents, Node.js 22.5+ and the MIT license. This page answers the questions developers most often ask about Graph Indexer, a local code graph and search engine that AI coding agents call over MCP. Each answer is self-contained and links to the page with the full detail. For setup start with [Install Graph Indexer](/install/), for the mechanics read [How Graph Indexer works](/how-it-works/), and for the measurements see the [benchmarks](/benchmarks/) and the comparison [Graph Indexer vs grep](/graph-indexer-vs-grep/). The eight tools are listed on the [tools page](/tools/), and supported languages on the [languages page](/languages/). ## Frequently asked questions ### What is Graph Indexer? Graph Indexer is a free, MIT-licensed code graph and search engine for AI coding agents, served locally over MCP. It parses your repository with tree-sitter and answers exact questions about references, callers, change impact and edits, in small replies. ### What is MCP and why does Graph Indexer use it? MCP, the Model Context Protocol, is the open standard through which AI agents call external tools. Graph Indexer runs as an MCP server over stdio, so any MCP-capable agent can call its eight read-only tools without a plugin written for that agent. ### How is Graph Indexer different from grep? Grep matches text; Graph Indexer binds each reference to the definition it points at. On 400 nestjs symbols checked against the TypeScript compiler, find_references reached 99.7% precision and 96.2% recall, while grep for the name reached 12.8% precision. ### Does Graph Indexer use embeddings or a language model? No. Search is lexical plus graph: BM25 over names, signatures, docs and bodies, a small concept thesaurus, and PageRank centrality. It needs no model, no embeddings, no downloads and no network. ### Which programming languages does Graph Indexer support? Sixteen bundled tree-sitter grammars: JavaScript, TypeScript, TSX, Python, Go, Java, Kotlin, Scala, C#, Rust, C, C++, Ruby, PHP, Bash and CSS. Binding is deepest for TypeScript, JavaScript, Python, Go, Java, C# and Rust. See the languages page for details. ### Does Graph Indexer send my code anywhere? Graph Indexer itself makes no network calls and sends no telemetry; it talks to the agent over stdio and never reads outside the repository. The agent still sends what it reads, including Graph Indexer replies, to its own model provider. ### Is Graph Indexer free? What does it cost? Graph Indexer is free and open source under the MIT license, with no account or API key. The only cost is your agent's model usage, which tends to fall: real Claude Code sessions answering code questions cost 16% less than without it. ### How fast is Graph Indexer? A full index of nestjs, 1,641 files and 96k lines, takes 3.7 seconds. After that only changed files are re-parsed. Warm graph tool calls take 1 to 4 ms, search about 30 ms, and hook or CLI queries answer in about 0.1 seconds. ### Does Graph Indexer work on large monorepos? Yes. It indexed the Twenty CRM monorepo, 28,512 files and about 2.3 million lines, in 51 seconds, then re-synced unchanged in 1.8 seconds. Precision against the TypeScript compiler was 99.9% and recall 92.4% on its server package. ### Where is the index stored, and should I commit it? The index is a SQLite file at .graph-indexer/index.db inside your repository. The init command adds the folder to .gitignore. Do not commit or share it: it holds excerpts of your code, so treat it like the repository. Deleting it is safe. ### Can the index be out of date? Not at answer time. Graph Indexer re-syncs with the files on disk before every tool call, using a file watcher plus stat sweeps, and re-validates files right before quoting their lines, so edits the agent made a second ago are included. ### How do I install the Graph Indexer plugin for Claude Code? Run /plugin marketplace add MaquinaTech/graph-indexer, then /plugin install graph-indexer@graph-indexer. The plugin bundles the MCP server, three hooks and a read-only code-structure sub-agent. Alternatively run npx graph-indexer init in the repository. ### Which AI coding agents does Graph Indexer work with? The init command configures Claude Code, Cursor, VS Code Copilot, Codex, Gemini CLI, OpenCode, Kilo Code, Junie, Zed and Devin. Any other client that can run an MCP server over stdio can use it through a manual configuration. ### What Node.js version does Graph Indexer need? Node.js 22.5 or newer, because the index uses the built-in node:sqlite module. There are no npm dependencies, no native builds and nothing to compile. Install and wire up your agents with npx graph-indexer init. ### What are the limits of Graph Indexer? It is not a type checker: generics, reflection, any and string-token dependency injection are only partly visible, and Java was the weakest language measured. Fixing real issues showed no measurable saving, and the agent benchmarks use small samples. --- Updated: 2026-10-08 · Graph Indexer 3.0.0 · https://graph-indexer.vercel.app/faq/