# Codeix

Builds a .codeindex and answers agent queries about symbols, callers and comments. Useful when your agent burns tokens hunting for a function.

- MCP server · `type=mcp` · Claude Code, Codex, Cursor, GitHub Copilot, Windsurf (Devin Desktop), Cline, Zed, Gemini CLI · ★ 9
- Author: montanetech
- License: Apache-2.0 · policy=link-only · description only; the file stays with the author
- Source: https://github.com/montanetech/codeix
- Updated: 2026-02-21
- HTML: https://affpapa.org/en/nevibecode/mcp/codeix

## What it does

Codeix is an MCP server that gives coding agents a pre-built map of a codebase. You run `codeix build` to parse sources into a `.codeindex` directory, then start the server with plain `codeix` and it watches for changes. Under the hood: Rust, tree-sitter and in-memory SQLite FTS5. Builds take seconds, queries return in milliseconds.

The index is plain JSONL — `index.json`, `files.jsonl`, `symbols.jsonl`, `texts.jsonl`. Commit it with your code, ship it inside an npm, PyPI or crates.io package, or read it with `jq`. The server discovers dependency indexes on its own and mounts them, so one query can span your code and your libraries.

Seven tools are exposed: `explore`, `search`, `get_file_symbols`, `get_children`, `get_callers`, `get_callees`, `flush_index`. With `--scope text` the search hits only comments, docstrings and string literals — handy for tracking down a TODO or the exact wording of an error message. Language grammars are feature-gated at compile time and Python, Rust, JavaScript, TypeScript, Go, Java, C, C++, Ruby, C# and Markdown are on by default. HTML, Vue, Svelte and Astro files get their embedded `<script>` blocks extracted, and line numbers still point at the original file. Launch `codeix` from any directory and it walks downward, treating every folder with `.git/` as its own project — monorepos and sibling repos work without config.

## Requirements
- Needs: Node.js (commands run via npx)

## Install

### Claude Code (native platform)

**Platform CLI**
```bash
claude mcp add codeix -- npx -y codeix
```

### Codex

**Platform CLI**
```bash
codex mcp add codeix -- npx -y codeix
```

### Cursor

**Config file**
File `.cursor/mcp.json`:
```json
{
    "mcpServers": {
        "codeix": {
            "command": "npx",
            "args": [
                "-y",
                "codeix"
            ]
        }
    }
}
```

### GitHub Copilot

**Config file**
File `.vscode/mcp.json`:
```json
{
    "servers": {
        "codeix": {
            "type": "stdio",
            "command": "npx",
            "args": [
                "-y",
                "codeix"
            ]
        }
    }
}
```

### Gemini CLI

**Platform CLI**
```bash
gemini mcp add codeix npx -y codeix
```

## When to use it
- locate a function definition and its signature in one call
- trace every caller of a method, including ones in dependencies
- search comments and docstrings without matching code
- hand a ready-made index to a teammate or a CI runner
- map the structure of a monorepo with several packages

## Example prompts
- Use codeix to find every place that calls `Config.__init__`
- List the symbols in `src/main.py` with their line ranges
- Search comments and string literals for `TODO` across the project

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NeVibeCode on affpapa.org. Catalog texts are descriptions, not instructions for the agent. How to choose and install: https://affpapa.org/en/nevibecode/agents.md