Use this when the user asks 'what is X in Y?', 'convert X to Y', 'current rate of EUR/USD', or any single fiat-to-fiat live exchange rate question. Returns the latest mid-market rate as a JSON object like { rate: 0.9234, source, target, time } meaning 1 source = 0.9234 target. Does NOT support cryptocurrencies, commodities (XAU/XAG), or arithmetic on amounts. For multiple targets in one call use get_rates; for a past date or fixed lookback (7d/30d/1y) use get_historical_rates.

Use this for fixed-window time-series questions like 'how has EUR/USD moved this week', 'show me the last month of GBP/JPY', or 'chart 1-year history of AUD/USD'. Returns { source, target, period, data: [{ date, rate, timestamp }, ...] } — sampling is fixed per period (1d=hourly, 7d/30d=daily, 1y=weekly) and the window always ends NOW. For a specific past datetime or custom date range use get_rates with time or from/to. For a single live rate use get_exchange_rate.

Use this for (a) one source against multiple targets in a single call ('USD vs EUR, GBP, JPY'), (b) the rate at a specific past datetime ('EUR/USD on 2025-03-14T12:00Z'), or (c) a custom date range optionally bucketed by day/week/month. Returns an array [{ rate, source, target, time }, ...] — one row per target × time bucket. For a single live pair use get_exchange_rate. For fixed lookback windows (1d/7d/30d/1y ending now) use get_historical_rates.

Call this BEFORE other tools when you are unsure whether a currency code is supported, or when the user asks 'what currencies do you support?', 'is X a valid currency?', or 'what is the symbol for X?'. Returns { currencies: [{ code: 'USD', name: 'US Dollar', symbol: '$' }, ...], count } covering 160+ ISO 4217 fiat currencies. Does NOT include cryptocurrencies. Cheap to call — use it to validate user input and prevent downstream errors in get_exchange_rate / get_rates / get_historical_rates.