rftools-mcp

MCP server for rftools.io — 213 RF & electronics calculators + 13 server-side simulation tools for AI agents.

Give Claude, Cursor, or any MCP-compatible AI assistant access to validated engineering calculators and heavy server-side simulations. Microstrip impedance, link budgets, filter design, converter sizing, antenna patterns, and 200+ more calculators — plus NEC2 antenna simulation, FDTD, Monte Carlo, SMPS analysis, EMI estimation, and more, all callable as MCP tools.

Tools

Calculator tools — no API key required

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. Runs locally — instant, no quota consumed.

"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}

Simulation tools — API key required

Server-side jobs that are too heavy for in-browser computation. Jobs run on shared compute (free tier) or a priority queue (Pro/API tier). Simulations typically complete in 15–120 seconds; queue wait may add additional time.

Quota: Free: 5 runs/month · Pro: 100/month · API tier: 10,000/month

list_simulation_tools

List all 13 available simulation tools with their jobType identifiers and parameter reference.

"What simulation tools are available?"
"Show me the RF simulation tools"

run_simulation

Submit a simulation job and wait for the result. Returns the full result JSON along with a link to the interactive results page on rftools.io.

"Synthesize a broadband matching network from 50Ω to 200Ω between 800–1200 MHz"
"Run a Monte Carlo tolerance analysis on a 2nd-order Butterworth low-pass filter at 1 GHz"
"Simulate a 3-element Yagi antenna at 144 MHz"
"Estimate radiated emissions from a 10cm trace carrying 50mA at 100 MHz"
"Run SMPS control loop stability analysis on my buck converter"

Parameters:

• jobType (required): Job type identifier — use list_simulation_tools to see all valid values
• params (required): Simulation parameters — use list_simulation_tools to see required params per job type

Available simulation tools:

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 213 Calculators

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

Calculators are bundled as pure TypeScript functions — no API calls, no network latency, no rate limits. The AI calls the function directly and gets instant results.

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

Simulation tools run server-side on rftools.io infrastructure (AWS Lambda + SQS + Fargate). The MCP server submits the job and polls until the result is ready, then returns the full result JSON inline.

AI Agent ←stdio→ rftools-mcp ←HTTPS + API key→ rftools.io API → SQS → worker
                                ←poll /jobs/{id}←
                                ←result JSON←

Machine-Readable Documentation

• rftools.io/llms.txt — Summary with API info and MCP setup
• rftools.io/llms-full.txt — Complete listing of all 203 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

Quick Start

Calculators work with no API key. For simulation tools, sign up at rftools.io and generate an API key from your dashboard.

Setup

Without API key — calculators only

All 210 calculators run locally with no sign-up required.

With API key — calculators + simulation tools

Sign up at rftools.io and generate an API key from your dashboard. Free accounts include 5 simulation runs/month. Pro: 100/month. API tier: 10,000/month.

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"],
      "env": {
        "RFTOOLS_API_KEY": "rfc_your_key_here"
      }
    }
  }
}

Omit the env block to use calculators only. Restart Claude Desktop after saving.

Claude Code

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

To add your API key:

claude mcp add rftools-mcp -e RFTOOLS_API_KEY=rfc_your_key_here -- npx -y rftools-mcp

Cursor

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

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

Windsurf

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

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

License

MIT