Codebase Index

AST-aware codebase indexing with semantic search, exposed as an MCP server. Think Cursor's codebase awareness, but for Claude Code (or any MCP client).

What it does: Parses your codebase with tree-sitter, chunks it intelligently (functions, components, hooks, stores, configs, classes with method extraction, types), embeds locally with Ollama, stores in LanceDB, and exposes semantic search via MCP.

Quick Start

# Prerequisites
brew install ollama
ollama serve
ollama pull nomic-embed-text

# Clone the tool (one-time)
git clone https://github.com/LevelPanic/codebase-index.git ~/codebase-index
cd ~/codebase-index && npm install

# In your repo
cd ~/your-project
npx tsx ~/codebase-index/src/cli/index.ts init          # generates config + wires .mcp.json
npx tsx ~/codebase-index/src/cli/index.ts index --full   # build the index

The init command automatically:

• Creates codebase-index.config.json with detected file patterns
• Adds .codebase-index/ to .gitignore
• Wires the MCP server into .mcp.json with the correct path

Restart Claude Code and it has search_codebase and get_file_context tools.

How It Works

Your repo files
     │
     ▼
  tree-sitter AST parsing
     │
     ▼
  Smart chunks (functions, components, hooks, stores, configs, classes, types, Prisma models)
     │
     ▼
  Ollama embeddings (nomic-embed-text, local, free)
     │
     ▼
  LanceDB vector storage (just files on disk)
     │
     ▼
  MCP server (stdio) → search_codebase / get_file_context

• Chunking is AST-aware — not dumb line splits. Each function, component, type definition, and Prisma model is its own chunk.
• Context-enriched — function chunks include referenced type definitions inline, so embeddings capture the full picture.
• Smart truncation — large chunks keep signature + head + tail instead of cutting off at the bottom (preserves return statements and JSX output).
• Class method extraction — large classes are split into individual method chunks instead of one truncated blob.
• Chunk type detection — React hooks (useXxx), Zustand/Redux stores, config objects, and barrel files are all detected and tagged.
• Small type batching — tiny adjacent type aliases are merged into a single chunk to reduce embedding calls.
• Embeddings are local — Ollama runs on your machine. No API keys, no network, no cost.
• Storage is embedded — LanceDB is just a directory on disk. No database server.
• Branch-aware — when on a feature branch, search results for modified files return live content from disk.

Configuration

The config file codebase-index.config.json goes at your repo root. It's optional — the tool works with zero config on any TypeScript/JavaScript project.

{
  "include": ["src/**/*.{ts,tsx,js,jsx}"],
  "exclude": ["**/node_modules/**", "**/dist/**"],
  "output": ".codebase-index",
  "baseBranch": "main",
  "embedding": {
    "provider": "ollama",
    "url": "http://localhost:11434",
    "model": "nomic-embed-text"
  },
  "tags": []
}

Tags

Tags let you add custom metadata dimensions to your chunks. Each tag has rules that match against file paths or content, and the tag values become filterable in the MCP search tool.

{
  "tags": [
    {
      "name": "layer",
      "defaultValue": "other",
      "rules": [
        { "pattern": "app/api/", "value": "backend" },
        { "pattern": "components/", "value": "frontend" },
        { "pattern": "lib/", "value": "shared" }
      ]
    },
    {
      "name": "domain",
      "defaultValue": "general",
      "rules": [
        { "pattern": "billing", "value": "billing" },
        { "pattern": "auth", "value": "auth" },
        { "contentPattern": "Stripe|stripe", "value": "billing" }
      ]
    }
  ]
}

With these tags configured, search_codebase automatically gets layer and domain as optional filter parameters.

Monorepo Example

{
  "include": [
    "apps/**/*.{ts,tsx,js,jsx}",
    "packages/**/*.{ts,tsx,js,jsx}",
    "apps/**/schema.prisma"
  ],
  "tags": [
    {
      "name": "platform",
      "defaultValue": "all",
      "rules": [
        { "pattern": "facebook", "value": "meta" },
        { "pattern": "tiktok", "value": "tiktok" },
        { "pattern": "google-ads", "value": "google" }
      ]
    },
    {
      "name": "app",
      "defaultValue": "unknown",
      "rules": [
        { "pattern": "apps/web/", "value": "web" },
        { "pattern": "apps/api/", "value": "api" },
        { "pattern": "packages/", "value": "packages" }
      ]
    }
  ]
}

CLI

Run commands via npx tsx ~/codebase-index/src/cli/index.ts <command> from your repo directory. Or create a shell alias:

alias cbi="npx tsx ~/codebase-index/src/cli/index.ts"

cbi init [--force]     Generate config + wire .mcp.json
cbi index              Incremental index (changed files only)
cbi index --full       Full reindex (drop and rebuild)
cbi stats              Show index statistics
cbi serve              Start MCP server (stdio)

Indexing

• Full index: Parses all files, embeds everything, rebuilds the database. ~15-20 min for ~5K files on Apple Silicon.
• Incremental index: Only re-embeds files changed since last indexed commit. ~10 seconds for typical daily changes.
• Stats: Shows chunk counts broken down by type and configured tags.

MCP Tools

search_codebase

Semantic search across the codebase. Returns relevant code chunks ranked by similarity.

Parameter	Type	Description
query	string	Natural language search query
limit	number	Max results (default 10)
<tag_name>	enum	Filter by any configured tag

get_file_context

Get all indexed chunks for a specific file. Shows the file's structure — functions, components, types.

Parameter	Type	Description
file_path	string	Relative path from repo root

Chunk Types

The chunker detects and labels each chunk:

Type	What it captures
function	Functions and arrow functions
component	React components (JSX-returning functions in .tsx/.jsx)
hook	React hooks (useXxx naming convention)
store	Zustand/Redux stores (create(), *Store, *Slice)
config	Plain object/array literals (route maps, constants, configs)
class	Class overview with method listing
method	Individual methods extracted from large classes
type	Type aliases, interfaces, enums
model	Prisma model/enum/type blocks
summary	File-level overview (imports + export listing)

Prerequisites

• Node.js 18+
• Git — the repo must be a git repository with at least one commit
• Ollama running locally with an embedding model (ollama serve && ollama pull nomic-embed-text)
• C++ compiler (for tree-sitter native module — Xcode CLI tools on macOS, build-essential on Linux)

How Freshness Works

The index tracks the base branch (default: main). When you're on a feature branch:

1. Search results are returned from the index as normal
2. If a result points to a file modified on your branch (git diff main...HEAD)
3. The tool reads the live file from disk and re-parses it
4. You get current content, not stale indexed content

This means the index only needs to track main — feature branch changes are always live.

Using in Multiple Repos

Clone once, use everywhere. Run init in each repo — it auto-detects the structure and wires everything up:

cd ~/project-a && npx tsx ~/codebase-index/src/cli/index.ts init
cd ~/project-b && npx tsx ~/codebase-index/src/cli/index.ts init

Each repo gets its own config, its own .codebase-index/ directory, and its own .mcp.json entry.

License

MIT