Current air quality at a place: PM2.5 and PM10 (µg/m³), US and European AQI, from Copernicus CAMS via Open-Meteo, with a signed receipt. Send latitude and longitude, or a city.

Verifiable random bytes for a draw, raffle or tie-break: an ECVRF output over your seed plus a proof anyone can check offline. The same seed always gives the same output, so publish the seed first.

HISTOR pre-flight for an MCP server: its signed record in the HISTOR transparency log — when the tool set was first seen, whether it changed, what the pattern scan found. Never contacts the server asked about.

MCP security: catch a rug pull or tool poisoning between two tools/list results of the same MCP server — the version you approved and the one it serves now. Flags instructions aimed at the model, override and concealment wording, credential and wallet paths, covert actions, hidden Unicode, new URLs and addresses, a dropped readOnlyHint, new command or path parameters and look-alike tool names; verdict unchanged, changed, review or suspicious, with a word diff per changed tool.

The nearest live public sensors to a point, one per layer asked for (weather, air, radiation, quake …), each with its reading, distance and source, and a signed receipt.

WARDEN verdict on an MCP server's tools/list: allow or block, a 0-1 score and every finding with the matched text (prompt injection, secret requests, exfiltration, hidden Unicode). Deterministic published rules, no network.

Current weather at a place: temperature (°C), humidity (%), pressure (hPa) and wind (m/s) from the nearest live Open-Meteo relay within 75 km, with a signed receipt. Send latitude and longitude, or a city.

Debug an x402 payment before you submit it — why does USDC answer invalid signature? Verifies the EIP-3009 transferWithAuthorization (EIP-712 signer, v, low s, validity window) and the seller's terms (payTo, amount, asset, network, bound nonce), and names the domain a failing signature was really made for, e.g. Base Sepolia's 'USDC' used for Base mainnet's 'USD Coin', the commonest reason an x402 payment reverts. Offline, deterministic, signed answer.