Compute the date of Easter Sunday for a given year using the Anonymous Gregorian algorithm (Meeus/Jones/Butcher). Also returns Good Friday, Ash Wednesday, Palm Sunday, Pentecost, and the day-of-year for Easter.

Check any public URL: status code, latency, final URL after redirects, and response headers. The uptime primitive for agent monitors.

Resolve an ENS name (e.g. vitalik.eth) to its Ethereum address - so an agent can turn a human-readable recipient into a payable address. Read-only on Ethereum mainnet.

Extract a <table> from an HTML string as JSON rows (header-keyed) or CSV. Useful for prices, schedules, sports stats, or anything an agent has already fetched as HTML. If multiple tables match, the first is used.

Validate an IBAN: country code, length, and the ISO 13616 mod-97 checksum.

Get the ISO 8601 week number, ISO day-of-week, quarter, and day-of-year for any date. Useful for fiscal/reporting calendars, weekly aggregations, and sprint planning.

Run a CSS selector against an HTML string and return the matches (text, attrs, and optionally outerHTML for each). The deterministic alternative to regex when you already have the HTML and know the selector - pairs with /api/render or any page you've fetched yourself.

Deep-compare two JSON values. Returns a list of changed/added/removed paths (capped at 1000 differences).

Flatten nested JSON to dot-path keys, or unflatten dot-path keys back to nested JSON. mode: flatten (default) | unflatten.

Validate, pretty-print (any indentation, 0-8 spaces), or minify JSON, optionally with object keys sorted. canonical: true returns the RFC 8785 (JCS) canonical form - keys sorted, no whitespace, ECMAScript number and string serialization - plus its SHA-256, for hashing and signing. Numbers are read as IEEE-754 doubles and a duplicate key keeps its last value. Returns parse errors with position when invalid.

Fit a least-squares line y = slope·x + intercept to two equal-length series. Returns slope, intercept, r² (variance explained), and optionally predicted y values for new x inputs - useful for trend extrapolation (e.g. project next quarter's revenue from the last 8 quarters).

Resolve an RFC 6901 JSON Pointer (e.g. /items/0/name) against a JSON value. Returns the value or found:false.

Extract a value from JSON by dot/bracket path, e.g. "items[2].name".

Deep-merge two JSON objects (b wins on conflicts; arrays are concatenated).

Infer a draft-07 JSON Schema from sample JSON document(s). Send one sample as json, or several as samples. Heuristic merge rules: required = keys present in every sample, conflicting types become a type union, integer widens to number, and string formats (date-time, date, email, uri, uuid) are detected from values. Complements json-validate.

Check whether a year is a leap year and get related info: days in that year, the next and previous leap years, and the Gregorian leap-year rule.

Atomically write (or release) a key only if its current value equals `expected` - the coordination primitive for distributed locks and optimistic concurrency across agents. Acquire a lock: expected=null + a value + ttlSeconds. Release it: expected=<your token> with no value (deletes on match). Update safely: expected=<old>, value=<new>. Returns whether it swapped and the current value.

Levenshtein edit distance between two strings, plus a 0-1 similarity ratio.

Compute the monthly (or per-period) payment on a fully-amortizing loan: mortgage, auto, student loan, business loan. Returns the periodic payment, total paid over the term, and total interest. Matches Excel's PMT(rate, nper, -principal). Use this when you just need the payment number, not the full per-period schedule (see amortization).

Atomically increment (or decrement) a numeric key and return the new value - a coordination primitive for counters, locks, and rate budgets shared across agents. Creates the key at 0 if absent. Retry safely with a requestId: a repeat with the same id returns the first answer and counts once; a retry without one counts again.