The argument for it is narrow and sound: an LLM asked for a microstrip width will confidently drop the copper-thickness correction, whereas run_calculation executes Hammerstad-Jensen and returns the number with its units. The free half needs no account at all — only the server-side simulations are metered.
An MCP server for rftools.io. The calculators are bundled as local functions — microstrip impedance, link budgets, filter design, converter sizing, antenna patterns — so an assistant calls the same validated code that runs on the site instead of doing the arithmetic itself. Heavier work is submitted to rftools.io as a simulation job.
- list_calculators — the available calculators, optionally filtered to rf, pcb, power, signal, antenna, general, motor, protocol, emc, thermal, sensor, unit-conversion or audio
- get_calculator_info — a calculator's inputs with units and defaults, its outputs, and the formula it uses
- run_calculation — run one by slug with your inputs; it executes locally, so it is instant and consumes no quota
- list_simulation_tools — the server-side jobs and their jobType identifiers, from NEC2 antenna simulation and FDTD S-parameters to SMPS loop stability and radiated-emission estimates
- run_simulation — submit a job and wait for the result; typically 15–120 seconds, plus queue time
Nothing for the calculators — clients launch it with npx -y rftools-mcp over stdio and all 232 run locally with no sign-up. The simulation tools need RFTOOLS_API_KEY from an rftools.io dashboard; free accounts get 5 simulation runs a month, Pro 100, and the API tier 10,000.
One command — npx -y rftools-mcp