/** Why a string was refused as an RFC 3339 instant. */
export type Rfc3339FailureReason = 
/** Input was not a string (null, undefined, number, object, …). */
'not_a_string'
/** Input did not match the accepted grammar. */
 | 'malformed'
/** Grammar matched but a field was outside its RFC 3339 range,
 *  including a day that does not exist in its month and hour 24. */
 | 'field_out_of_range'
/** time-second was 60. See LEAP SECONDS above. */
 | 'leap_second'
/** The instant is not a safe integer count of milliseconds. */
 | 'not_representable';
/** Outcome of {@link parseRfc3339}. `ok: false` carries a reason and never
 *  an instant, so a caller cannot read a time out of a failed parse. */
export type Rfc3339ParseResult = {
    ok: true;
    ms: number;
} | {
    ok: false;
    reason: Rfc3339FailureReason;
};
/**
 * Parse an RFC 3339 instant strictly, for use at a security boundary.
 *
 * Returns the instant in milliseconds since the Unix epoch, or a reason. It
 * never returns NaN and never throws: a caller that ignores `ok` gets a type
 * error rather than a value that compares false in both directions.
 *
 * Invariants:
 *   - Only the grammar documented at the head of this module is accepted;
 *     an absent offset, a date-only value, whitespace, or an empty string is
 *     `malformed`.
 *   - Every field is range-checked, so 2026-02-30 and 24:00:00 are
 *     `field_out_of_range` rather than instants.
 *   - Equal instants written with different offsets return the same `ms`.
 *   - Sub-millisecond digits are validated and then truncated away.
 */
export declare function parseRfc3339(value: unknown): Rfc3339ParseResult;
/**
 * Render an instant as the RFC 3339 UTC spelling this SDK emits:
 * YYYY-MM-DDTHH:MM:SS.sssZ, always three fractional digits.
 *
 * The counterpart to {@link parseRfc3339}, and byte-identical to
 * `new Date(ms).toISOString()` for every instant inside the four-digit-year
 * range — tests/rfc3339.test.ts pins that equality, so switching an emission
 * site to this function cannot move any artifact's bytes.
 *
 * It exists so that a file which verifies timestamps never has to construct
 * a Date at all. `new Date(x)` accepts a string as readily as a number, and
 * that ambiguity is the whole of F-04; `formatRfc3339` takes a `number`, so
 * handing it an artifact's field is a compile error rather than a silent
 * reparse. That is what lets the boundary guard ban `new Date(` outright
 * instead of trying to tell emission and interpretation apart by eye.
 *
 * A fractional millisecond count is TRUNCATED toward zero rather than
 * refused, because that is precisely what `new Date(ms)` does (TimeClip,
 * ECMA-262 21.4.1.15) and this function's whole value is being
 * indistinguishable from it. Durations arrive from division often enough —
 * a day divided into sevenths, a sub-millisecond timeout — that refusing them
 * would turn arithmetic a caller has always been allowed to do into an
 * exception at an emission site that cannot fail closed usefully.
 *
 * @throws RangeError when `ms` is not finite, or falls outside the
 * representable four-digit-year range. Outside that range `new Date(ms)`
 * emits an ISO 8601 expanded-year spelling, which is not RFC 3339 and which
 * {@link parseRfc3339} refuses, so returning one would mint an artifact this
 * SDK's own verifiers can never read. An emission site holds an instant it
 * computed itself; a value outside four-digit years is a bug at the caller.
 */
export declare function formatRfc3339(ms: number): string;
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