codenano

The lightweight AI coding agent SDK extracted from Claude Code.

Built by extracting Claude Code's production architecture. All the power, none of the bloat. Open source, fully customizable, production-ready.

💡 Based on Claude Code — The same battle-tested engine that powers Anthropic's official coding assistant, now available as a standalone SDK.

Why codenano?

🚀 Claude Code's Core, 97% Lighter

• 5,500 lines of pure, focused code
• Claude Code: 150,000+ lines (IDE integration, UI, etc.)
• Same agent engine, zero overhead

⚡ What Claude Code Does, You Can Do

npm install codenano

Build your own Claude Code in 60 seconds. No IDE required. No restrictions.

🎯 Battle-Tested Architecture

Extracted from Claude Code's production engine. Proven at scale, optimized for developers.

Quick Start

Get your first agent running in 3 lines:

import { createAgent, coreTools } from 'codenano'

const agent = createAgent({
  model: 'claude-sonnet-4-6',
  tools: coreTools(),  // Read, Edit, Write, Glob, Grep, Bash
})

const result = await agent.ask('Read package.json and summarize it')
console.log(result.text)

That's it. No complex setup. No configuration hell. Just pure productivity.

Streaming? Built-in.

for await (const event of agent.stream('What files are here?')) {
  if (event.type === 'text') process.stdout.write(event.text)
}

Multi-turn conversations? Easy.

const session = agent.session()
await session.send('Read main.ts')
await session.send('Now explain what it does')

Custom Tools

import { defineTool } from 'codenano'
import { z } from 'zod'

const readFile = defineTool({
  name: 'ReadFile',
  description: 'Read a file from disk',
  input: z.object({ path: z.string() }),
  execute: async ({ path }) => fs.readFileSync(path, 'utf-8'),
  isReadOnly: true,
})

const agent = createAgent({
  model: 'claude-sonnet-4-6',
  tools: [readFile],
})

codenano vs Claude Code

Same engine. Different philosophy.

Think of it this way:

• Claude Code = Complete car (engine + body + interior)
• codenano = Just the engine (build your own car)

When to use codenano:

• Building custom AI coding tools
• Integrating agents into your product
• Need full control over behavior
• Want to understand how it works

When to use Claude Code:

• Just want to code with AI assistance
• Prefer official Anthropic support
• Happy with IDE integration

What You Get

🛠️ 17 Built-in Tools

Ready to use, zero configuration:

• File Operations: Read, Edit, Write
• Code Search: Glob (pattern matching), Grep (regex search)
• Execution: Bash commands
• Advanced: Web search, web fetch, notebooks, LSP, and more

🎨 Three Tool Presets

coreTools()      // Essential 6 tools
extendedTools()  // Core + 5 more
allTools()       // All 17 tools

🔧 Production Features

• ✅ Auto-compact (handles context overflow)
• ✅ Retry & fallback (resilient API calls)
• ✅ Token budgeting (cost control)
• ✅ Permission system (security)
• ✅ Hook system (lifecycle events)
• ✅ Streaming support (real-time output)

System Structure

Clean, modular architecture:

codenano/
  src/
    agent.ts           # Core agent loop
    session.ts         # Multi-turn conversations
    tools/             # 17 built-in tools
    prompt/            # System prompt builder
    provider.ts        # Anthropic SDK + Bedrock
    compact.ts         # Auto-compact logic
  tests/               # 191 tests
  examples/            # Ready-to-run demos
  docs/                # Comprehensive guides

191 tests. 100% production-ready.

Documentation

Testing

# Unit tests (191 tests)
npm test

# With coverage
npx vitest run --coverage

# Integration tests (requires API key)
ANTHROPIC_API_KEY=sk-xxx npm run test:integration

Roadmap

Coming Soon:

• Hook system (16 event types)
• Sub-agent spawning
• Memory system (cross-session persistence)
• MCP protocol support
• Session persistence
• Git integration
• Cost tracking

Why Choose codenano?

For Startups

Ship your AI coding product faster. Stop wrestling with bloated frameworks. Get to market in days, not months.

For Enterprises

Production-ready from day one. Battle-tested architecture, comprehensive testing, full control over your stack.

For Developers

Actually enjoyable to use. Clean APIs, great docs, zero magic. Build what you want, how you want.

License

MIT License.

Get Started Now

npm install codenano

Questions? Check the docs or open an issue.

Ready to build? See examples/ for inspiration.