Verified Facts

ClaudeCommunityby Data Butler

Verified Facts returns one official figure per lookup: you send a key such as uk/income-tax/personal-allowance and an optional max_age, and get back the value, unit and period, the official source URL (gov.uk, IRS, Bundesfinanzministerium, central banks), the date a person last checked it against that source, a fresh or stale flag, and an Ed25519 signature that can be checked against databutler.dev/.well-known/jwks.json. It covers 496 figures: UK income tax, National Insurance, benefits, vehicle tax and MOT rules and government service fees; US federal tax brackets, Social Security, Medicare and retirement limits; German income tax and social-insurance thresholds; Bank of England, Fed and ECB policy rates; UK exam dates. Three read-only tools: get_fact (one or several keys), resolve_fact (turns a plain-language question such as "NI primary threshold" into a key), and what_changed_since (every figure that changed after a given date, with before and after values and sources). No account or API key. The same facts are served as plain web pages at databutler.dev/f/<key> and are described by an open specification, Verified Facts v0.2, at databutler.dev/facts.