CalcsLive MCP Server

Enable AI agents to perform unit-aware engineering calculations via Model Context Protocol (MCP)

Transform AI assistants like Claude into powerful engineering calculation tools with automatic unit conversion, dependency resolution, and professional-grade accuracy.

What is This?

The CalcsLive MCP Server connects AI agents to CalcsLive's calculation engine via the Model Context Protocol (MCP). This enables AI to:

• Perform complex engineering calculations with proper unit handling
• Automatically convert between unit systems (metric imperial)
• Resolve multi-step calculation dependencies
• Access 75+ unit categories with 500+ units
• Validate calculations with engineering accuracy

Example

User: "Calculate hydro power for a flow rate of 150 m/s with a head of 25 meters"

AI (via CalcsLive MCP):

{
  "power": {
    "value": 36787.5,
    "unit": "kW"
  }
}

AI automatically handles the unit-aware calculation: P = g H Q

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Prerequisites

1. Node.js 18+ installed on your system
2. CalcsLive Account - Sign up at calcs.live
3. MCP API Key - Create from your Account > API Keys
   • Select "MCP Integration (AI Agents)" as service type
   • Free users: Get 30-day trial (starts on first API call)
   • Premium users: Full unlimited access

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Quick Start

1. Install Dependencies

cd /path/to/calcslive-mcp-server
npm install

2. Build the Server

npm run build

3. Configure Claude Desktop

Edit your Claude Desktop configuration file:

Location:

• Windows: %APPDATA%\Claude\claude_desktop_config.json
• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Linux: ~/.config/Claude/claude_desktop_config.json

Add CalcsLive MCP server:

{
  "mcpServers": {
    "calcslive": {
      "command": "node",
      "args": [
        "/absolute/path/to/calcslive-mcp-server/dist/index.js"
      ],
      "env": {
        "CALCSLIVE_API_KEY": "your-mcp-api-key-here",
        "CALCSLIVE_API_URL": "https://www.calcs.live"
      }
    }
  }
}

Important:

• Replace /absolute/path/to/calcslive-mcp-server with your actual installation path
• Replace your-mcp-api-key-here with your actual MCP API key from CalcsLive

4. Restart Claude Desktop

Quit and restart Claude Desktop to load the MCP server.

5. Verify Installation

In Claude Desktop, you should see the CalcsLive tools available. Try asking:

"What CalcsLive tools do you have available?"

Claude should list calcslive_run_script, calcslive_calculate, and calcslive_validate.

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Claude Code (VS Code Extension) Setup

If you're using Claude Code in VS Code, use the Claude CLI for easier configuration:

1. Install and Build

cd /path/to/calcslive-mcp-server
npm install
npm run build

2. Add MCP Server via Claude CLI

Use the claude mcp add command with stdio transport:

Linux/macOS:

claude mcp add --transport stdio calcslive \
  --env CALCSLIVE_API_KEY=your-mcp-api-key-here \
  --env CALCSLIVE_API_URL=https://www.calcs.live \
  -- node /absolute/path/to/calcslive-mcp-server/dist/index.js

Windows PowerShell:

claude mcp add --transport stdio calcslive `
  --env CALCSLIVE_API_KEY=your-mcp-api-key-here `
  --env CALCSLIVE_API_URL=https://www.calcs.live `
  -- node C:\absolute\path\to\calcslive-mcp-server\dist\index.js

Important Notes:

• Replace /absolute/path/to/calcslive-mcp-server (or C:\absolute\path\to\... on Windows) with your actual installation path
• Replace your-mcp-api-key-here with your actual API key
• Use absolute path to dist/index.js (required by MCP)
• The -- before node is required to separate MCP options from the command
• For local development, use CALCSLIVE_API_URL=http://localhost:3000

3. Verify in VS Code

Restart your VS Code window or reload Claude Code extension. The CalcsLive MCP tools should now be available to Claude Code AI.

Test it:

"Calculate the torque for a 2 HP motor running at 100 rpm"

Claude Code should use the calcslive_run_script tool to perform the calculation.

Alternative: Manual Configuration

If Claude CLI is not available, you can manually edit the Claude Code MCP configuration file, but the CLI method is strongly recommended for reliability.

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Available Tools

calcslive_run_script NEW

Run stateless unit-aware calculations from Physical Quantity (PQ) script definitions. No article creation needed - fully stateless and on-the-fly.

Example Usage:

User: "Calculate the area of a circle with radius 5 cm in mm"

AI uses: calcslive_run_script
- pqs: [
    {
      sym: "r",
      description: "radius",
      value: 5,
      unit: "cm"
    },
    {
      sym: "A",
      description: "circle area",
      expression: "pi * r^2",
      unit: "cm"
    }
  ]
- outputs: {
    A: { unit: "mm" }
  }

Response:

Calculation completed with 1 output

Results:
 circle area (A): 7853.982 mm = pi * r^2

Detailed calculation:
{
  "inputs": {
    "r": { "value": 5, "unit": "cm", "baseValue": 0.05, "baseUnit": "m" }
  },
  "outputs": {
    "A": { "value": 7853.982, "unit": "mm", "baseValue": 0.007854, "baseUnit": "m" }
  }
}

Key Features:

• No article creation required (stateless)
• Define calculations on-the-fly with PQ JSON
• Supports Greek letters (, , , , etc.)
• Automatic dependency resolution
• Unit conversion for inputs and outputs
• Mathematical expressions with MathJS

calcslive_calculate

Perform unit-aware calculations using existing CalcsLive articles.

Example Usage:

User: "Calculate the kinetic energy of a 1500 kg car traveling at 25 m/s"

AI uses: calcslive_calculate
- articleId: "kinetic-energy"
- inputs: {
    mass: { value: 1500, unit: "kg" },
    velocity: { value: 25, unit: "m/s" }
  }
- outputs: {
    energy: { unit: "kJ" }
  }

Response:

{
  "energy": {
    "value": 468.75,
    "unit": "kJ",
    "expression": "0.5 * mass * velocity^2"
  }
}

calcslive_validate

Discover available inputs/outputs for a calculation article.

Example Usage:

User: "What parameters does the hydro power calculation accept?"

AI uses: calcslive_validate
- articleId: "hydro-power"

Response:

{
  "articleTitle": "Hydro Power Calculation",
  "inputPQs": [
    {
      "symbol": "Q",
      "description": "Flow rate",
      "unit": "m/s",
      "categoryId": "volumetric_flow_rate"
    },
    {
      "symbol": "H",
      "description": "Head",
      "unit": "m",
      "categoryId": "length"
    }
  ],
  "outputPQs": [
    {
      "symbol": "P",
      "description": "Power output",
      "unit": "kW",
      "expression": "rho * g * H * Q * eta"
    }
  ]
}

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Usage Examples

Example 1: Unit Conversion

User: "Convert 65 mph to km/h"

AI: Uses CalcsLive to create a simple calculation:

Input: velocity = 65 mph
Output: velocity in km/h = 104.6 km/h

Example 2: Multi-Step Engineering Calculation

User: "Calculate pump power needed for 100 gallons per minute at 50 psi with 85% efficiency"

AI:

1. Validates pump calculation article
2. Converts units (gpm m/s, psi Pa)
3. Performs calculation with dependencies
4. Returns power in kW

Example 3: Complex Physics Problem

User: "A projectile is launched at 45 with initial velocity 30 m/s. What's the maximum height?"

AI:

1. Uses projectile motion calculation article
2. Inputs: angle = 45, velocity = 30 m/s
3. Calculates: max_height = (v sin) / (2g) = 22.96 m

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Development

Build & Watch

npm run dev

This runs TypeScript in watch mode for development.

Testing Locally

Run the server directly to test:

export CALCSLIVE_API_KEY=your_key_here
npm start

You should see:

CalcsLive MCP server running on stdio
API Base: https://www.calcs.live
Ready to perform unit-aware calculations for AI agents!

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API Rate Limits

User Tier	Rate Limit	Trial Period
Free	60 calls/min	30 days
Premium	60 calls/min	N/A (unlimited)
Enterprise	Unlimited	N/A

Note: Trial starts automatically on first API call. Upgrade to Premium before trial expires for continued access.

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Troubleshooting

"API key not found or inactive"

Solution: Check your API key in Account > API Keys

• Ensure service type is "MCP Integration (AI Agents)"
• Verify key is active (not expired)
• Copy key exactly (no extra spaces)

"Article not found"

Solution:

• Ensure article is set to Public access level
• Use the article's Short ID, not UUID
• Verify you own the article (can't access others' articles via API)

"Trial has expired"

Solution: Upgrade to Premium to restore MCP access

Claude Desktop Not Finding Tools

Solution:

1. Check config file syntax (valid JSON)
2. Verify path to dist/index.js is correct
3. Ensure npm run build completed successfully
4. Restart Claude Desktop completely
5. Check Claude Desktop logs for errors

"Unknown unit" Error

Solution:

• CalcsLive supports both superscript (m) and caret (m^3) notation
• Use caret notation if typing: m^3 instead of m
• Check Units Reference for valid units

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Advanced Usage

Custom API Base URL (Development)

For local development or custom deployments:

{
  "mcpServers": {
    "calcslive": {
      "env": {
        "CALCSLIVE_API_URL": "http://localhost:3000",
        "CALCSLIVE_API_KEY": "your-dev-key"
      }
    }
  }
}

Multiple API Keys

You can configure separate MCP servers for different projects:

{
  "mcpServers": {
    "calcslive-project-a": {
      "command": "node",
      "args": ["..."],
      "env": {
        "CALCSLIVE_API_KEY": "project-a-key"
      }
    },
    "calcslive-project-b": {
      "command": "node",
      "args": ["..."],
      "env": {
        "CALCSLIVE_API_KEY": "project-b-key"
      }
    }
  }
}

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Resources

• CalcsLive Platform: calcs.live
• MCP Documentation: modelcontextprotocol.io
• Units Reference: calcs.live/help/units-reference
• API Integration Guide: calcs.live/help/api-integration
• Create Calculations: calcs.live/editor

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Support

• Documentation: calcs.live/help
• Community: GitHub Discussions
• Premium Support: Available for Premium/Enterprise subscribers

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License

MIT License - See LICENSE file for details

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What's Next?

1. Create Custom Calculations: Build your own calculation articles at calcs.live/editor
2. Explore Unit Categories: Browse 75+ categories at Units Reference
3. Upgrade for More: Premium plans unlock unlimited calculations
4. Share & Collaborate: Make calculations public for others to use via MCP

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