# urdb-mcp

<a href="https://glama.ai/mcp/servers/GetMystAdmin/urdb-mcp">
  <img width="380" height="200" src="https://glama.ai/mcp/servers/GetMystAdmin/urdb-mcp/badge" />
</a>

MCP server for [URDB](https://urdb.io). 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](https://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).

```json
{
  "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>`:

| Category | Covers |
|----------|--------|
| **Components** (11) | Resistor and capacitor colour/SMD codes, E-series snapping, LED resistors, RC time constants, series/parallel networks |
| **Circuits** (16) | 555 timers, op-amps, filters, buck/boost converters, MOSFET gate drive, Ohm's law, zener and LM317 regulators, Schmitt triggers |
| **Power & Wiring** (13) | PCB trace width and impedance, wire gauge, voltage drop, fuse sizing, heat sinks, battery packs, solar sizing, via current |
| **Firmware** (22) | UART baud rates, CAN bit timing, PLL dividers, timer prescalers, CRC, IEEE 754, struct padding, bitfields, watchdogs, Intel HEX |
| **RF & Signals** (7) | Antenna lengths, LoRa airtime, path loss, VSWR, Nyquist, FFT bins, wavelength |
| **Mechanical** (4) | Stepper motors, E-steps, gear ratios, tap drill sizes |
| **Reference** (3) | Pinouts, logic levels, MCU comparison |

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

| Tool | Description |
|------|-------------|
| `urdb_search` | Search products by name or keyword, with integrity scores |
| `urdb_get_product` | Full integrity breakdown across 7 dimensions |
| `urdb_get_changes` | Documented enshittification events for a product |
| `urdb_list_products` | List/filter products by category, brand, score |

## 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:

```bash
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](https://urdb.io/api)

## Configuration

| Variable | Required | Description |
|----------|----------|-------------|
| `URDB_API_KEY` | yes | Your key from [urdb.io/settings/api-keys](https://urdb.io/settings/api-keys) |
| `URDB_API_URL` | no | API base URL. Defaults to `https://urdb.io/api/v1`. |

## Development

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

## License

MIT