电子硬件计算器服务

urdb-mcp

MCP server for URDB. Gives your AI assistant 76 electronics, hardware and firmware calculators — plus the product integrity database tracking downgrades, shrinkflation, warranty cuts and enshittification.

Ask "what UBRR do I need for 9600 baud on a 16 MHz AVR?" and get 103 with the error percentage and the worked derivation, instead of a plausible-sounding guess.

Setup

1. Get an API key at urdb.io/settings/api-keys (free tier available)

2. Add to your MCP host

Claude Desktop config lives at ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows).

{
  "mcpServers": {
    "urdb": {
      "command": "npx",
      "args": ["urdb-mcp"],
      "env": {
        "URDB_API_KEY": "urdb_live_your_key_here"
      }
    }
  }
}

3. Restart your host

Calculators are metered separately from product data — 1,000 calculator calls a day on the free tier, so an agent working through a design won't exhaust your quota on arithmetic.

Example prompts

• "Size the current-limiting resistor for a blue LED on 5 V"
• "Give me every valid CAN bit timing for 500 kbit/s on a 40 MHz clock"
• "What trace width do I need for 3 A with a 20 °C rise on an external layer?"
• "Decode this struct's padding for a 32-bit target"
• "Is 1000 km realistic on LoRa SF12?"
• "Which laptops have the highest integrity scores?"
• "Has the KitchenAid Stand Mixer gotten worse over the years?"

Tools

Call tools/list to see the current set — the calculator catalogue is fetched from the server at runtime, so it grows without a package update.

Calculators

76 tools across seven categories, named calc_<name>:

Each returns the answer, machine-readable values, the worked derivation and a link to the same tool on the web at https://urdb.io/tools/<name>.

Product data

How it works

This package is a thin stdio→HTTPS proxy for https://urdb.io/api/v1. It contains no calculation logic: the catalogue and every tool's JSON Schema are fetched from /api/v1/tools when the server starts.

That means a calculator added to URDB shows up here on your next restart, and a fix reaches you via a deploy rather than npm update. If the API is unreachable the server still starts and serves the product tools, and retries the catalogue on the next tools/list.

Calculators follow published standards where one exists — IPC-2221 and IPC-2141 for trace geometry, IEC 60063 for E-series, IEC 60127 for fuses, ISO 11898-1 for CAN, IEEE 754 for floats. Where a result is an extrapolation rather than a measurement, the tool says so.

REST API

Everything here is available over plain HTTP:

curl -H "Authorization: Bearer $URDB_API_KEY" https://urdb.io/api/v1/tools

curl -X POST https://urdb.io/api/v1/tools/uart-baud-rate \
  -H "Authorization: Bearer $URDB_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"clockHz": 16000000, "baud": 9600, "family": "avr-normal"}'

Full docs: urdb.io/api

Configuration

Development

npm run typecheck
npm run build     # bundle to dist/index.js
npm test          # stdio end-to-end against a mock API

License

MIT