rftools-mcp

MCP server for rftools.io — 197 RF & electronics calculators for AI agents.

Give Claude, Cursor, or any MCP-compatible AI assistant access to validated engineering calculators. Microstrip impedance, link budgets, filter design, converter sizing, antenna patterns, and 190+ more — all callable as MCP tools.

Quick Start

npx rftools-mcp

That's it. The server starts on stdio and is ready for connections.

Setup

Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

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

Restart Claude Desktop. You now have 197 calculators available.

Claude Code

claude mcp add rftools-mcp -- npx -y rftools-mcp

Cursor

Add to .cursor/mcp.json in your project:

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

Windsurf

Add to ~/.codeium/windsurf/mcp_config.json:

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

Tools

list_calculators

List available calculators, optionally filtered by category.

"List all RF calculators"
"What antenna calculators are available?"
"Show me power electronics calculators"

Parameters:

• category (optional): rf, pcb, power, signal, antenna, general, motor, protocol, emc, thermal, sensor, unit-conversion, audio

get_calculator_info

Get detailed info about a calculator — inputs with units/defaults, outputs, and the formula used.

"What inputs does the microstrip impedance calculator need?"
"Show me the buck converter calculator parameters"

Parameters:

• slug (required): Calculator identifier (e.g. "microstrip-impedance")

run_calculation

Run a calculator with specific inputs. Returns results with units and a link to the interactive version on rftools.io.

"Calculate microstrip impedance for a 0.3mm trace on 0.2mm Rogers RO4003C"
"What's the link budget for a 2.4 GHz link over 500m?"
"Size a buck converter: 12V in, 3.3V out, 2A"

Parameters:

• slug (required): Calculator identifier
• inputs (required): Object with input values, e.g. {"traceWidth": 0.3, "substrateHeight": 0.2}

Example Conversations

PCB Design

You: I need a 50-ohm microstrip on 1.6mm FR4 with 1oz copper. What trace width?

AI: Calls run_calculation with microstrip-impedance → A trace width of ~2.9mm gives you 50.2 Ω on 1.6mm FR4 (εr=4.2). View on rftools.io →

RF Link Budget

You: Will my 100mW 915 MHz LoRa link work at 2km with 3dBi antennas?

AI: Calls run_calculation with rf-link-budget → Received power: -72 dBm. With LoRa sensitivity at -137 dBm, you have 65 dB of link margin. Easily workable. View on rftools.io →

Power Electronics

You: Design a buck converter: 24V input, 5V output, 3A load, 500kHz switching.

AI: Calls run_calculation with buck-converter → Duty cycle: 20.8%, inductor: 17.4 μH, output cap: 22 μF. View on rftools.io →

All 197 Calculators

| Category | Count | Examples | |----------|------:|---------| | RF & Microwave | 21 | Microstrip impedance, VSWR/return loss, Smith chart, link budget, noise figure cascade, radar range, free-space path loss | | PCB Design | 14 | Trace width for current, differential pair, controlled impedance, via calculator, crosstalk, decoupling capacitor | | Power Electronics | 18 | Buck converter, boost converter, flyback, LDO thermal, battery life, MOSFET dissipation, solar panel sizing | | Signal Processing | 14 | Filter designer, ADC SNR, FFT bin resolution, PLL loop filter, BER/SNR, Johnson noise | | Antenna Design | 8 | Dipole, patch, Yagi-Uda, horn, parabolic dish, loop, EIRP, beamwidth | | General Electronics | 16 | Ohm's law, op-amp gain, 555 timer, BJT bias, MOSFET operating point, Schmitt trigger, crystal load capacitance | | Motor Control | 17 | DC motor speed, stepper, BLDC, servo, PID tuning, gear ratio, H-bridge selection | | Communications | 10 | UART baud rate, I2C pull-up, SPI timing, CAN bus, USB termination, RS-485, Ethernet, Modbus | | EMC/EMI | 14 | Shielding effectiveness, EMI filter, ferrite bead, ESD/TVS diode, radiated emission estimate, common-mode choke | | Thermal | 6 | Heatsink calculator, junction temperature, thermal via array, PCB trace temperature | | Sensor Interface | 17 | NTC thermistor, RTD, thermocouple, Wheatstone bridge, load cell, photodiode, 4-20 mA loop transmitter | | Unit Conversion | 17 | dBm↔Watts, frequency↔wavelength, AWG wire, capacitor code, temperature, inductance, data rate | | Audio Electronics | 17 | Speaker crossover, room modes, headphone power, class-D efficiency, audio transformer, equalizer Q |

Why Use This Instead of Asking the AI to Calculate?

LLMs are unreliable at arithmetic. They may:

• Use simplified formulas that omit corrections (e.g. copper thickness in microstrip)
• Confuse units (mils vs mm, dBm vs dBW)
• Accumulate rounding errors
• Confidently present wrong answers

This MCP server calls the exact same validated calculator code that runs on rftools.io. Hammerstad-Jensen for microstrip, Friis for path loss, exact dB/linear conversions — real engineering formulas, not LLM approximations.

How It Works

The server bundles all 197 calculator functions from rftools.io into a single file. Each calculator is a pure TypeScript function — no API calls, no network latency, no rate limits. The AI calls the function directly and gets instant, accurate results.

AI Agent ←stdio→ rftools-mcp ←direct call→ calculator function

Machine-Readable Documentation

• rftools.io/llms.txt — Summary with API info and MCP setup
• rftools.io/llms-full.txt — Complete listing of all 197 calculators with inputs, outputs, units, and URLs

Links

• Website: rftools.io
• npm: npmjs.com/package/rftools-mcp
• Blog: rftools.io/blog
• Announcement: rftools.io Now Speaks MCP

License

MIT