Lien

/ljɛ̃/ — French for "link"

Give AI deep understanding of your codebase through semantic search. 100% local, 100% private.

Lien connects AI coding assistants like Cursor to your codebase through the Model Context Protocol (MCP). Ask questions in natural language, get precise answers from semantic search—all running locally on your machine.

📚 Full Documentation | 🚀 Getting Started | 🔍 How It Works

Features

• 🔒 100% Local & Private - All code analysis happens on your machine
• 🚀 Semantic Search - Natural language queries: "How does authentication work?"
• 🎯 MCP Integration - Works seamlessly with Cursor and other MCP-compatible tools
• ⚡ Fast - Sub-500ms queries, minutes to index large codebases
• 🆓 Free Forever - No API costs, no subscriptions, no usage limits
• 📦 Framework-Aware - Auto-detects Node.js, Laravel, Shopify; supports 15+ languages
• 🏗️ Monorepo Support - Index multiple frameworks in one repository
• 📊 Complexity Analysis - Human-friendly metrics: test paths, mental load, time to understand
• 🔍 Impact Analysis - Find all dependents before refactoring with risk assessment

Quick Start

# Install
npm install -g @liendev/lien

# Setup in your project
cd /path/to/your/project
lien init
lien index

# Configure Cursor - create .cursor/mcp.json
{
  "mcpServers": {
    "lien": {
      "command": "lien",
      "args": ["serve"]
    }
  }
}

# Restart Cursor and start asking questions!

👉 Full installation guide

MCP Tools

Lien exposes 6 powerful tools via Model Context Protocol:

| Tool | Description | |------|-------------| | semantic_search | Natural language code search | | find_similar | Find similar code patterns | | get_files_context | Get file context with test associations | | list_functions | List symbols by pattern | | get_dependents | Impact analysis (what depends on this?) | | get_complexity | Tech debt analysis with human-friendly metrics |

Complexity Metrics

Lien tracks code complexity with intuitive outputs:

• 🔀 Test paths - Cyclomatic complexity as "needs ~X tests for full coverage"
• 🧠 Mental load - Cognitive complexity with nesting penalty
• ⏱️ Time to understand - Halstead effort as readable duration (~2h 30m)
• 🐛 Estimated bugs - Halstead prediction (Volume / 3000)

Documentation

• Installation - npm, npx, or local setup
• Getting Started - Step-by-step configuration for Cursor
• Configuration - Customize indexing, thresholds, performance
• CLI Commands - Full command reference
• MCP Tools - Complete API reference for all 6 tools
• How It Works - Architecture overview

Supported Languages

TypeScript • JavaScript • Vue • Python • PHP • Liquid • Go • Rust • Java • C/C++ • Ruby • Swift • Kotlin • C# • Scala • Markdown

Frameworks: Node.js, Laravel, Shopify (Liquid themes)

Contributing

Contributions welcome! See CONTRIBUTING.md for guidelines.

Support

• 🐛 Issues - Report bugs or request features
• 💬 Discussions - Ask questions and share ideas

License

AGPL-3.0 © Alf Henderson

Lien is free forever for local use. The AGPL license ensures that:

• ✅ You can use Lien locally without restrictions
• ✅ You can modify and distribute Lien freely
• ✅ Improvements get contributed back to the community
• ✅ We can sustain long-term development

For questions about licensing, contact us at [email protected]

Made with ❤️ for developers who value privacy and local-first tools.