@leanspec/mcp - MCP Server Integration Wrapper

Status: ✅ Complete · Priority: High · Created: 2025-11-18 · Tags: mcp, integration, npm-package, developer-experience

Project: lean-spec
Team: Core Development

Overview

Create a lightweight CLI wrapper that makes lean-spec mcp more discoverable and easier to use. The existing lean-spec CLI has many features, making MCP setup less obvious. This dedicated package provides a simple entry point for users to quickly onboard MCP with their preferred IDE/tools.

Problem: lean-spec is a full-featured CLI tool. When users configure MCP servers in their IDE, they need to know to use lean-spec mcp, which isn't obvious. Also, the package name lean-spec doesn't clearly indicate MCP functionality.

Solution: Ship @leanspec/mcp as a thin wrapper. IDEs can call npx @leanspec/mcp directly, which just delegates to lean-spec mcp. This makes the MCP server more discoverable and the package name more intuitive.

Design

Package Structure

@leanspec/mcp/
├── bin/
│   └── leanspec-mcp.js   # Thin wrapper CLI
├── package.json          # Depends on lean-spec
└── README.md             # Quick start guide

How It Works

The package is a simple passthrough:

1. User adds MCP server to their IDE config: npx @leanspec/mcp
2. When IDE needs the server, npx auto-installs @leanspec/mcp and its lean-spec dependency
3. Script delegates to: lean-spec mcp
4. MCP server starts and IDE can communicate with it

No interaction needed - the IDE handles everything.

Usage in IDE Configs

Claude Desktop (claude_desktop_config.json):

{
  "mcpServers": {
    "leanspec": {
      "command": "npx",
      "args": ["-y", "@leanspec/mcp"]
    }
  }
}

Cline (VS Code settings.json):

{
  "cline.mcpServers": {
    "leanspec": {
      "command": "npx",
      "args": ["-y", "@leanspec/mcp"]
    }
  }
}

Zed (settings.json):

{
  "context_servers": {
    "leanspec": {
      "command": "npx",
      "args": ["-y", "@leanspec/mcp"]
    }
  }
}

Key Design Decisions

Pure passthrough: Just delegates to lean-spec mcp, no logic needed.

Better naming: @leanspec/mcp is more intuitive than lean-spec mcp for MCP use cases.

Auto-install: npx automatically installs both @leanspec/mcp and its lean-spec dependency when needed.

No interaction: MCP servers are called by IDEs, not by users directly. No wizard needed.

Simpler docs: Users just copy-paste the config snippet, IDE handles the rest.

Plan

• Create minimal package structure in packages/mcp/
• Write simple passthrough script (delegates to lean-spec mcp)
• Add lean-spec as dependency in package.json
• Create README with config examples for different IDEs
• Test with Claude Desktop, Cline, Zed
• Publish to npm as @leanspec/mcp
• Update main docs with @leanspec/mcp examples

Test

• Config with npx @leanspec/mcp works in Claude Desktop
• Config with npx @leanspec/mcp works in Cline
• Config with npx @leanspec/mcp works in Zed
• Server starts correctly when IDE calls it
• npx auto-installs dependencies on first run
• Works on macOS, Windows, Linux
• Package size is minimal (<5KB)

Notes

Why This Approach

Maximum simplicity: Just a ~10 line passthrough script.

No complexity: No IDE detection, no config merging, no interaction. Users just copy config.

Better naming: Package name clearly indicates MCP functionality.

Zero maintenance: All logic lives in lean-spec mcp, wrapper just delegates.

Discoverability: Searching for "leanspec mcp" finds the right package immediately.

Implementation

#!/usr/bin/env node
const { spawn } = require('child_process');

// Simply delegate to lean-spec mcp
const child = spawn('lean-spec', ['mcp'], { stdio: 'inherit' });
child.on('exit', (code) => process.exit(code));

Documentation Example

Users see this in the docs:

Quick Setup

Add to your Claude Desktop config:

{
  "mcpServers": {
    "leanspec": {
      "command": "npx",
      "args": ["-y", "@leanspec/mcp"]
    }
  }
}

Restart Claude Desktop. Done!

Dependencies

• lean-spec - The actual MCP server (peer dependency)

Related

• Existing lean-spec mcp command (what this delegates to)