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RFrftools.io

MCP · rftools-mcp 2.4.0

rftools.io for AI agents

The rftools MCP server gives an AI assistant the same calculators and simulations as this site. It runs on your machine through rftools-mcp, you can start without an account, and every result states the formula or model it came from.

calculators
241
calculators
simulation tools
13
simulation tools
MCP tools
24
MCP tools
reference resources
49
reference resources
Install ↓See the tools

What the server does

  • Calculators. All 241 calculators in 13 categories run inside the server, with the same formulas as this site. An agent can search them in seven languages, read a calculator's inputs as a JSON Schema, run it, or solve for the input value that reaches a target.
  • Simulations. 13 server-side tools, among them antenna analysis, FDTD, filter tolerance, PDN impedance and satellite links, run as jobs on rftools.io. The server submits the job, reports its progress and summarises the result.
  • Reference data. Frequency bands, connectors, standard values, component codes and PCB specifications are published as MCP resources: 49 entries in 5 domains.
  • Provenance. Every calculation and simulation result carries the formula or model, the assumptions and the valid range it was computed under.

Install

Pick your client. Each setup below runs the server through npx, which comes with Node.js, and none of them needs a key to start.

Claude Desktop

Add this to ~/Library/Application Support/Claude/claude_desktop_config.json on macOS or %APPDATA%\Claude\claude_desktop_config.json on Windows, then restart Claude Desktop.

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

Claude Code

Run this in a terminal, then start a new session.

Claude Codebash
claude mcp add rftools -- npx -y rftools-mcp

Cursor

Add this to .cursor/mcp.json in a project, or to ~/.cursor/mcp.json to use it in every project.

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

Keys and limits

A free key from your dashboard raises the limits. Set it as RFTOOLS_API_KEY: add "env": { "RFTOOLS_API_KEY": "rfc_your_key_here" } to the server's entry in a JSON config file, or add -e RFTOOLS_API_KEY=rfc_your_key_here to the Claude Code command. This is what the server itself says about keys:

  • run_calculation computes in this server against the bundled calculator registry: no key, no network call, no allowance spent.
  • solve_calculation calls the metered POST /calculate/solve endpoint, which needs an API key — the same one POST /calculate itself requires. Unlike run_calculation, this does not run locally or for free. Set RFTOOLS_API_KEY. A free key: https://rftools.io/dashboard
  • Without RFTOOLS_API_KEY a job still runs, on the free lane — but only a job that takes no file. Uploading a file needs an API key; set RFTOOLS_API_KEY.
  • Free tier: 5 runs/month. Pro: 100/month. API tier: 10 000/month.

Tools

The server lists 24 tools. 8 of them only read and compute; the rest start a simulation job on rftools.io or make a metered call to its REST API, as the Effect column shows. The question each tool answers is what an agent reads when it chooses a tool. Tool names and parameters are the same in every language.

Calculator tools (6)

  • list_calculators

    List Calculators

    List the 241 RF and electronics calculators on rftools.io, or those in one category.

    Read-only
  • search_calculators

    Search Calculators

    Find the calculators that fit a task described in words, in English or in any of the languages rftools.io is published in.

    Read-only
  • get_calculator_info

    Get Calculator Info

    Describe one calculator: its inputs with units, defaults and bounds, its outputs, formula and keywords.

    Read-only
  • get_calculator_schema

    Get Calculator Schema

    Give the exact input contract of one calculator as a JSON Schema, with its outputs, formula reference and page URL.

    Read-only
  • run_calculation

    Run Calculation

    Compute a calculator's outputs for given inputs, locally in this server, with no API key.

    Read-only
  • solve_calculation

    Solve Calculation

    Find the value of one calculator input that makes an output equal a target, such as the trace width that gives 50 Ω on microstrip-impedance.

    Metered call

One tool per simulation (13)

  • simulate_antenna_sim

    Wire Antenna Simulator (NEC-2)

    Solve your own wire antenna with the NEC-2 method of moments: dipoles, Yagis, verticals and loops, element by element.

    Starts a job
  • simulate_emi_radiated

    EMI Radiated Emissions Estimator

    Estimate radiated emissions from PCB loops and cables using Paul's analytical DM/CM models.

    Starts a job
  • simulate_eye_diagram

    Eye Diagram from S-Parameters

    Upload a Touchstone (.s2p) file and generate a PRBS eye diagram.

    Starts a job
  • simulate_fdtd_sparam

    FDTD Transmission Line Simulator

    Solve microstrip stubs, coupled-line filters, via transitions, and step discontinuities across a ladder of named solve modes — from a 2D cross-section in seconds to a fine 3D openEMS field solve.

    Starts a job
  • simulate_filter_monte_carlo

    RF Filter Monte Carlo Analysis

    Analyse how component tolerances affect your filter's passband ripple and stopband rejection.

    Starts a job
  • simulate_impedance_matching

    Broadband Impedance Matching Synthesizer

    Synthesize L, Pi, T, or ladder matching networks for broadband impedance transformation.

    Starts a job
  • simulate_magnetics_optimizer

    Magnetics & Transformer Design Optimizer

    NSGA-II optimizer finds Pareto-optimal core and winding designs across 40 cores (E, ETD, PQ, RM and toroids) and 104 core/material combinations, with TDK and Ferroxcube ferrites and Micrometals iron powder.

    Starts a job
  • simulate_pdn_impedance

    PDN Impedance Analyzer & Decoupling Capacitor Optimizer

    Choose decoupling capacitors for a PCB power delivery network.

    Starts a job
  • simulate_radar_detection

    Radar Detection Performance Monte Carlo

    Compute probability of detection (Pd) vs range for pulsed radar systems.

    Starts a job
  • simulate_rf_cascade

    RF Cascade Budget Analyzer

    Compute cascaded noise figure, gain, IIP3, and P1dB for an N-stage RF signal chain using Friis formulas.

    Starts a job
  • simulate_sat_link_budget

    Satellite & Terrestrial Link Budget

    Compute probabilistic link margins using ITU-R propagation models (P.618 rain, P.676 gaseous, P.840 cloud) with climate data read from the ITU-R maps at your site.

    Starts a job
  • simulate_smps_control_loop

    SMPS Control Loop Stability Analyzer

    Model switch-mode power supply control loops using small-signal transfer functions.

    Starts a job
  • simulate_sparam_pipeline

    S-Parameter Analysis Pipeline

    Upload up to 4 Touchstone files and get component values (L, C, R, Q, self-resonance) for a single component, plus insertion loss, return loss, group delay, TDR and passband ripple — all in one automated report.

    Starts a job

Simulation jobs (5)

  • list_simulation_tools

    List Simulation Tools

    List the 13 server-side simulation job types with their tool names, parameters, file rules, free-lane bounds and time budgets.

    Read-only
  • submit_simulation

    Submit Simulation

    Start a simulation job named by its job type and return at once with its id, without waiting for the result.

    Starts a job
  • get_simulation_status

    Get Simulation Status

    Report how far a submitted simulation job has got.

    Read-only
  • get_simulation_result

    Get Simulation Result

    Fetch the result of a finished simulation job.

    Read-only
  • run_simulation

    Run Simulation

    Run a simulation job named by its job type and wait a bounded time for its result.

    Starts a job

Reference data

Each reference domain is a resource template. A host that shows resources to the model lets an agent cite a band edge or a connector's frequency range from the same data as the reference pages.

  • rftools://reference/bands/{id}

    Frequency bands

  • rftools://reference/connectors/{id}

    RF connectors

  • rftools://reference/values/{id}

    Standard values

  • rftools://reference/codes/{id}

    Component marking codes

  • rftools://reference/pcb/{id}

    PCB specifications

Try asking

Once the server is connected, ask in plain language. For example:

  • What trace width gives a 50 Ω microstrip on 1.6 mm FR-4? Use rftools.
  • Work out a 2.4 GHz link budget: 20 dBm transmit power, 3 dBi antennas at each end, 2 km apart. How much margin is there over a −90 dBm receiver sensitivity?
  • Run a Monte Carlo tolerance analysis on a 5th-order Chebyshev low-pass filter at 100 MHz with 5% parts, and tell me the yield.
  • Simulate the PDN impedance of a 100 × 80 mm board and suggest decoupling capacitors that keep it under 10 mΩ up to 100 MHz.
  • Look up the 2.4 GHz ISM band in the rftools reference data and cite where its limits come from.