codegraph/README.md

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# 🔮 CodeGraph

### Supercharge Claude Code with Semantic Code Intelligence

**2x faster exploration • 40% fewer tokens • Zero API costs**

[![npm version](https://img.shields.io/npm/v/@colbymchenry/codegraph.svg)](https://www.npmjs.com/package/@colbymchenry/codegraph)
[![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
[![Node.js](https://img.shields.io/badge/Node.js-18+-green.svg)](https://nodejs.org/)

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---

## 🚀 Why CodeGraph?

Without CodeGraph, Claude Code spawns expensive exploration agents that make dozens of API calls to understand your codebase. **CodeGraph changes that.**

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### ❌ Without CodeGraph
```
Exploring codebase...
↳ 21 tool calls
↳ 37,700 tokens consumed
↳ 70 seconds
↳ ~$0.50-2.00 per exploration
```

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### ✅ With CodeGraph
```
Building context...
↳ 1-3 tool calls
↳ Local MCP (0 tokens)
↳ 35 seconds
↳ $0.00 for exploration
```

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### 📊 Real-World Results

| Metric | Without CodeGraph | With CodeGraph | Improvement |
|--------|-------------------|----------------|-------------|
| **Speed** | 70s | 35s | **2x faster** |
| **Tokens per task** | ~40,000 | ~0 (local) | **40,000 saved** |
| **Cost per exploration** | $0.50-2.00 | $0.00 | **Free** |

---

## ✨ Key Features

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### 🧠 Smart Context Building
One tool call returns everything Claude needs—entry points, related symbols, and code snippets. No more expensive exploration agents.

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### 🔍 Semantic Search
Find code by meaning, not just text. Search for "authentication" and find `login`, `validateToken`, `AuthService`—even with different naming conventions.

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### 📈 Impact Analysis
Know exactly what breaks before you change it. Trace callers, callees, and the full impact radius of any symbol.

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### 🌍 15+ Languages
TypeScript, JavaScript, Python, Go, Rust, Java, C#, PHP, Ruby, C, C++, Swift, Kotlin—all with the same API.

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### 🔒 100% Local
No data leaves your machine. No API keys. No external services. Everything runs on your local SQLite database.

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### ⚡ Always Fresh
Git hooks automatically sync the index on every commit. Your code intelligence is always up to date.

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---

## 🎯 Quick Start

### Step 1: Install

```bash
npm install -g @colbymchenry/codegraph
```

### Step 2: Configure Claude Code MCP

Add to your `~/.claude.json` in the `mcpServers` section:

```json
{
  "mcpServers": {
    "codegraph": {
      "type": "stdio",
      "command": "codegraph",
      "args": ["serve", "--mcp"]
    }
  }
}
```

### Step 3: Add Global Instructions

Create or append to `~/.claude/CLAUDE.md`:

```markdown
## CodeGraph

CodeGraph builds a semantic knowledge graph of codebases for faster, smarter code exploration.

### If `.codegraph/` exists in the project

**Use codegraph tools for faster exploration.** These tools provide instant lookups via the code graph instead of scanning files:

| Tool | Use For |
|------|---------|
| `codegraph_search` | Find symbols by name (functions, classes, types) |
| `codegraph_context` | Get relevant code context for a task |
| `codegraph_callers` | Find what calls a function |
| `codegraph_callees` | Find what a function calls |
| `codegraph_impact` | See what's affected by changing a symbol |
| `codegraph_node` | Get details + source code for a symbol |

**When spawning Explore agents in a codegraph-enabled project:**

Tell the Explore agent to use codegraph tools for faster exploration:

Explore the codebase to understand [task].

This project has CodeGraph initialized - use these tools for faster lookups:
- codegraph_search to find relevant symbols
- codegraph_callers/codegraph_callees to trace call graphs
- codegraph_context to get related code for the task
- codegraph_node with includeCode=true to read specific functions

**For quick lookups in the main session:**
- Use `codegraph_search` instead of grep for finding symbols
- Use `codegraph_callers`/`codegraph_callees` to trace code flow
- Use `codegraph_impact` before making changes to see what's affected

**Note:** CodeGraph provides CODE context, not product requirements. For new features, clarify UX preferences with the user before implementing.

### If `.codegraph/` does NOT exist

At the start of a session, ask the user if they'd like to initialize CodeGraph:

"I notice this project doesn't have CodeGraph initialized. Would you like me to run `codegraph init -i` to build a code knowledge graph? This enables faster code exploration via semantic search and call graph analysis."

If they agree, run:
codegraph init -i
```

### Step 4: Initialize Your Projects

```bash
cd your-project
codegraph init -i    # Initialize and index
```

### Step 5: Restart Claude Code

Restart Claude Code for the MCP server to load. The tools will be available in any project with a `.codegraph/` directory.

---

## 📋 Requirements

- Node.js >= 18.0.0

---

## 💻 CLI Usage

```bash
codegraph init [path]       # Initialize in a project
codegraph index [path]      # Full index
codegraph sync [path]       # Incremental update
codegraph status [path]     # Show statistics
codegraph query <search>    # Search symbols
codegraph context <task>    # Build context for AI
codegraph hooks install     # Install git auto-sync hook
codegraph serve --mcp       # Start MCP server
```

## 📖 CLI Commands

### `codegraph init [path]`

Initialize CodeGraph in a project directory. Creates a `.codegraph/` directory with the database and configuration.

```bash
codegraph init                    # Initialize in current directory
codegraph init /path/to/project   # Initialize in specific directory
codegraph init --index            # Initialize and immediately index
codegraph init --no-hooks         # Skip git hook installation
```

### `codegraph index [path]`

Index all files in the project. Extracts functions, classes, methods, and their relationships.

```bash
codegraph index                   # Index current directory
codegraph index --force           # Force full re-index
codegraph index --quiet           # Suppress progress output
```

### `codegraph sync [path]`

Incrementally sync changes since the last index. Only processes added, modified, or removed files.

```bash
codegraph sync                    # Sync current directory
codegraph sync --quiet            # Suppress output
```

### `codegraph status [path]`

Show index status and statistics.

```bash
codegraph status
```

Output includes:
- Files indexed, nodes, edges
- Nodes by kind (functions, classes, methods, etc.)
- Files by language
- Pending changes (if any)
- Git hook status

### `codegraph query <search>`

Search for symbols in the codebase by name.

```bash
codegraph query "authenticate"           # Search for symbols
codegraph query "User" --kind class      # Filter by kind
codegraph query "process" --limit 20     # Limit results
codegraph query "validate" --json        # Output as JSON
```

### `codegraph context <task>`

Build relevant code context for a task. Uses semantic search to find entry points, then expands through the graph to find related code.

```bash
codegraph context "fix checkout bug"
codegraph context "add user authentication" --format json
codegraph context "refactor payment service" --max-nodes 30
```

### `codegraph hooks`

Manage git hooks for automatic syncing.

```bash
codegraph hooks install    # Install post-commit hook
codegraph hooks remove     # Remove hook
codegraph hooks status     # Check if hook is installed
```

### `codegraph serve`

Start CodeGraph as an MCP server for AI assistants.

```bash
codegraph serve                          # Show MCP configuration help
codegraph serve --mcp                    # Start MCP server (stdio)
codegraph serve --mcp --path /project    # Specify project path
```

## 🔌 MCP Tools Reference

When running as an MCP server, CodeGraph exposes these tools to AI assistants:

### `codegraph_explore` ⭐ Recommended for complex tasks

Deep exploration that returns a condensed brief. Use this for features, refactoring, or multi-file changes to keep your main context clean.

```
codegraph_explore(task: "implement user authentication", keywords: "auth,login,user")
```

**Returns:** Key files, entry points, types, functions, data flow, and suggested next steps.

### `codegraph_context`

Build context for a specific task. Good for focused queries.

```
codegraph_context(task: "fix checkout validation bug", maxNodes: 20)
```

### `codegraph_search`

Quick symbol search by name. Returns locations only.

```
codegraph_search(query: "UserService", kind: "class", limit: 10)
```

### `codegraph_callers` / `codegraph_callees`

Find what calls a function, or what a function calls.

```
codegraph_callers(symbol: "validatePayment", limit: 20)
codegraph_callees(symbol: "processOrder", limit: 20)
```

### `codegraph_impact`

Analyze what code would be affected by changing a symbol.

```
codegraph_impact(symbol: "UserService", depth: 2)
```

### `codegraph_node`

Get details about a specific symbol. Use `includeCode: true` only when needed.

```
codegraph_node(symbol: "authenticate", includeCode: true)
```

### `codegraph_status`

Check index health and statistics.

### Context Usage Best Practices

| Approach | Context Impact | When to Use |
|----------|----------------|-------------|
| `codegraph_explore` | **Low** - condensed summary | Complex features, refactoring |
| Multiple tool calls | **High** - each result accumulates | Avoid for complex tasks |
| `codegraph_context` | **Medium** | Focused, single-area queries |

## 📚 Library Usage

CodeGraph can also be used as a library in your Node.js applications:

```typescript
import CodeGraph from '@colbymchenry/codegraph';

// Initialize a new project
const cg = await CodeGraph.init('/path/to/project');

// Or open an existing one
const cg = await CodeGraph.open('/path/to/project');

// Index with progress callback
await cg.indexAll({
  onProgress: (progress) => {
    console.log(`${progress.phase}: ${progress.current}/${progress.total}`);
  }
});

// Search for symbols
const results = cg.searchNodes('UserService');

// Get callers of a function
const node = results[0].node;
const callers = cg.getCallers(node.id);

// Build context for a task
const context = await cg.buildContext('fix login bug', {
  maxNodes: 20,
  includeCode: true,
  format: 'markdown'
});

// Get impact radius
const impact = cg.getImpactRadius(node.id, 2);

// Sync changes
const syncResult = await cg.sync();

// Clean up
cg.close();
```

## ⚙️ How It Works

### 1. Extraction

CodeGraph uses [tree-sitter](https://tree-sitter.github.io/) to parse source code into ASTs. Language-specific queries (`.scm` files) extract:

- **Nodes**: Functions, methods, classes, interfaces, types, variables
- **Edges**: Calls, imports, extends, implements, returns_type

Each node gets a unique ID based on its kind, file path, name, and line number.

### 2. Storage

All data is stored in a local SQLite database (`.codegraph/codegraph.db`):

- **nodes** table: All code entities with metadata
- **edges** table: Relationships between nodes
- **files** table: File tracking for incremental updates
- **node_vectors** / **vector_map**: Embeddings for semantic search (using sqlite-vss)

### 3. Reference Resolution

After extraction, CodeGraph resolves references:

1. Match function calls to function definitions
2. Resolve imports to their source files
3. Link class inheritance and interface implementations
4. Apply framework-specific patterns (Express routes, etc.)

### 4. Semantic Search

CodeGraph uses local embeddings (via [@xenova/transformers](https://github.com/xenova/transformers.js)) to enable semantic search:

1. Code symbols are embedded using a transformer model
2. Queries are embedded and compared using cosine similarity
3. Results are ranked by relevance

### 5. Graph Queries

The graph structure enables powerful queries:

- **Callers/Callees**: Direct call relationships
- **Impact Radius**: BFS traversal to find all potentially affected code
- **Dependencies**: What a symbol depends on
- **Dependents**: What depends on a symbol

### 6. Context Building

When you request context for a task:

1. Semantic search finds relevant entry points
2. Graph traversal expands to related code
3. Code snippets are extracted
4. Results are formatted for AI consumption

## ⚙️ Configuration

The `.codegraph/config.json` file controls indexing behavior:

```json
{
  "version": 1,
  "projectName": "my-project",
  "languages": ["typescript", "javascript"],
  "exclude": [
    "node_modules/**",
    "dist/**",
    "build/**",
    "*.min.js"
  ],
  "frameworks": ["express", "react"],
  "maxFileSize": 1048576,
  "gitHooksEnabled": true
}
```

### Options

| Option | Description | Default |
|--------|-------------|---------|
| `languages` | Languages to index (auto-detected if empty) | `[]` |
| `exclude` | Glob patterns to ignore | `["node_modules/**", ...]` |
| `frameworks` | Framework hints for better resolution | `[]` |
| `maxFileSize` | Skip files larger than this (bytes) | `1048576` (1MB) |
| `gitHooksEnabled` | Enable git hook installation | `true` |

## 🌐 Supported Languages

| Language | Extension | Status |
|----------|-----------|--------|
| TypeScript | `.ts`, `.tsx` | Full support |
| JavaScript | `.js`, `.jsx`, `.mjs` | Full support |
| Python | `.py` | Full support |
| Go | `.go` | Full support |
| Rust | `.rs` | Full support |
| Java | `.java` | Full support |
| C# | `.cs` | Full support |
| PHP | `.php` | Full support |
| Ruby | `.rb` | Full support |
| C | `.c`, `.h` | Full support |
| C++ | `.cpp`, `.hpp`, `.cc` | Full support |
| Swift | `.swift` | Basic support |
| Kotlin | `.kt` | Basic support |

## 🔧 Troubleshooting

### "CodeGraph not initialized"

Run `codegraph init` in your project directory first.

### Indexing is slow

- Check if `node_modules` or other large directories are excluded
- Use `--quiet` flag to reduce console output overhead
- Consider increasing `maxFileSize` if you have large files to skip

### MCP server not connecting

1. Ensure the project is initialized and indexed
2. Check the path in your MCP configuration is correct
3. Verify `codegraph serve --mcp` works from the command line
4. Check Claude Code logs for connection errors

### Missing symbols in search

- Run `codegraph sync` to pick up recent changes
- Check if the file's language is supported
- Verify the file isn't excluded by config patterns

---

## 📄 License

MIT

---

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**Made for the Claude Code community** 🤖

[Report Bug](https://github.com/colbymchenry/codegraph/issues) · [Request Feature](https://github.com/colbymchenry/codegraph/issues)

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