/**
 * Extract 5h / 7d percent-used from a response headers object. Returns
 * null when neither header is present so callers can early-return without
 * touching the cache. Header lookup is case-insensitive against the
 * candidate names listed above.
 */
export declare function parseUsageHeadersIfPresent(headers: Record<string, string | string[] | undefined>): {
    fiveHourPct?: number;
    sevenDayPct?: number;
} | null;
/**
 * Merge a partial usage observation (5h and/or 7d) into the per-account
 * cache. Preserves any window the caller didn't observe — e.g. if only
 * the 5h header was in the response, the 7d value from the prior cache
 * survives. `resets_at` is intentionally not synthesised here; we only
 * have it from the /api/oauth/usage endpoint body, never from headers.
 *
 * No-op when both inputs are undefined. Best-effort write; failures are
 * swallowed (same policy as writeUsageCache — usage telemetry must never
 * cascade into a request error).
 */
export declare function updateUsageCacheFromHeaders(accountsDirPath: string, email: string, fiveHourPct: number | undefined, sevenDayPct: number | undefined): void;