Ground

Ground is a reference data API that gives Claude access to standardized classification systems, real-time world information, and unit conversion utilities. Think ISO codes, currency data, country information, timezone lookups, and measurement conversions without needing to maintain static datasets or build conversion logic yourself. You'd reach for this when you need Claude to work with structured reference data that changes over time, like converting between units, looking up official country codes, or pulling current information about world entities. It runs over streamable HTTP, so no local installation required.