mcp-server-inverspec

An MCP (Model Context Protocol) server that guides AI assistants through reverse-engineering a technical specification from an undocumented codebase — the Inverspec workflow.

Supported stacks: Rails, Laravel, PHP+Smarty, Next.js, Express, Spring Boot, FastAPI, Flask, Django, and any other framework the AI can read.

Plans

Pro: $19/month or $190/year (2 months free) — Get a license: https://inverspec.lemonsqueezy.com

Quick start

For macOS users: npx may fail due to PATH conflicts on some systems (for example, ImageMagick's import command). We recommend the global npm installation below.

Claude Desktop — global npm install (recommended for macOS)

Step 1: Install globally

npm install -g mcp-server-inverspec

Step 2: Check the full binary path

which mcp-server-inverspec
# Example: /opt/homebrew/bin/mcp-server-inverspec
#     /usr/local/bin/mcp-server-inverspec

Step 3: Add it to claude_desktop_config.json

~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "inverspec": {
      "command": "node",
      "args": ["/opt/homebrew/lib/node_modules/mcp-server-inverspec/dist/index.js"]
    }
  }
}

Adjust the args path based on the output of which mcp-server-inverspec.
Example: if it shows /opt/homebrew/bin/mcp-server-inverspec, the actual file is
/opt/homebrew/lib/node_modules/mcp-server-inverspec/dist/index.js.

For Pro users (with license key):

{
  "mcpServers": {
    "inverspec": {
      "command": "node",
      "args": ["/opt/homebrew/lib/node_modules/mcp-server-inverspec/dist/index.js"],
      "env": {
        "INVERSPEC_LICENSE_KEY": "YOUR-LICENSE-KEY"
      }
    }
  }
}

Claude Desktop — npx (Linux / Windows)

Use this on non-macOS systems, or when no PATH conflicts occur:

{
  "mcpServers": {
    "inverspec": {
      "command": "npx",
      "args": ["-y", "mcp-server-inverspec"]
    }
  }
}

For Pro users:

{
  "mcpServers": {
    "inverspec": {
      "command": "npx",
      "args": ["-y", "mcp-server-inverspec"],
      "env": {
        "INVERSPEC_LICENSE_KEY": "YOUR-LICENSE-KEY"
      }
    }
  }
}

Cursor

Add this to .cursor/mcp.json:

{
  "mcpServers": {
    "inverspec": {
      "command": "npx",
      "args": ["-y", "mcp-server-inverspec"],
      "env": {
        "INVERSPEC_LICENSE_KEY": "YOUR-LICENSE-KEY"
      }
    }
  }
}

Claude Code (CLI)

claude mcp add inverspec -- npx -y mcp-server-inverspec

Usage

Important: Inverspec no longer provides filesystem tools. It returns phase prompt templates only. Saving generated documents is handled by your MCP client or by manual copy/paste.

Finding your project path

Inverspec requires the absolute path to your project root.

macOS / Linux — open a terminal, navigate to your project, and run pwd:

cd ~/Development/my-app
pwd
# → /Users/your-username/Development/my-app

Windows — open the folder in Explorer, then click the address bar to reveal the full path.

Can't find the path? You can also zip your project and upload it in clients that support file upload:

# macOS / Linux
cd ~/Development
zip -r my-app.zip my-app \
  --exclude "*/node_modules/*" \
  --exclude "*/.git/*" \
  --exclude "*/target/*"

Recommended prompt — run all phases in one go

Open a new chat in Claude Desktop and type:

Create a technical specification for /Users/your-username/Development/my-app.
Run Phase 0 through 6 without stopping for confirmation.
For each phase output, save it to docs/spec/ inside the project.

You can also run a single phase:

Run only Phase 2 (data model) on /Users/your-username/Development/my-app

How it works

Each phase tool accepts a projectPath and returns a detailed Markdown prompt template. The AI uses that template to analyze your project and generate phase documents. Inverspec does not read or write your files directly.

Output

After a full run, save the generated documents under:

docs/spec/ README.md - Executive summary and navigation guide 00-inventory.md - File tree, stack summary 01-architecture.md - Architecture map, request flow 02-data-model.md - ER diagram, entity sheets 03-features.md - API catalogue, feature cards 04-business-logic.md - Domain rules, state machines 05-operations.md - Config, deploy, observability

claude.ai vs Claude Desktop

Requirements

• Node.js 18 or later
• An MCP-compatible client (Claude Desktop, Cursor, Claude Code, etc.)

Feedback & Support

Found a bug or have a feature request? → Open an Issue

Have a question or idea to discuss? → Start a Discussion

License

ISC