/**
 * Renders the rejection of a value off the format ladder, naming where it was written. Every source that
 * accepts a format renders through this, so no two of them can come to name different ladders.
 */
export declare function formatReportFormatRejection(source: string, value: string): string;
/** Narrows a raw value to a point on the format ladder. */
export declare function isReportFormat(value: string): value is ReportFormat;
/**
 * Reads the format the environment names. An unrecognized value resolves to nothing at all, since falling back
 * would pick a rendering nobody chose and hide a misspelling for the life of the shell.
 *
 * An unset or empty variable names no format rather than resolving to `text`, which keeps the read symmetric
 * with the one the loudness ladder performs and leaves room for a level below the environment.
 */
export declare function readReportFormatEnv(env: NodeJS.ProcessEnv): ReportFormatRead;
/**
 * Carries the resolved format down the spawned chain, so `--json` reaches every process rather than the first.
 * Deliberately not a keyed variable: it changes how a run reports and never what a command concludes, so
 * folding it into the cache key would stop a machine-readable run from hitting a pass a prose one recorded.
 */
export declare const REPORT_FORMAT_ENV_VAR = "NMR_REPORT_FORMAT";
/**
 * The points on the format ladder. Both are spelled out rather than leaving `text` implicit in the variable's
 * absence, so a format exported for a shell is overridable on one invocation in either direction.
 */
export declare const REPORT_FORMATS: readonly ["text", "json"];
/** How nmr renders its own verdicts, which is never the output of the commands it runs. */
export type ReportFormat = (typeof REPORT_FORMATS)[number];
/** The format the environment names, if any, or the message naming why its value could not be read. */
export type ReportFormatRead = {
    ok: true;
    format?: ReportFormat;
} | {
    ok: false;
    error: string;
};
/**
 * Resolves the format this process reports in: the flag, then the environment, then `text`.
 *
 * Two levels where the loudness ladder has four. A repo wanting JSON for everyone working in it is not a case
 * anyone has, and detecting a harness would hand every agent JSON in place of the prose the shipped guidance
 * teaches; either is additive later.
 *
 * Total by construction. The environment was validated as it was read, so no rejection is left for this to
 * report and the whole ladder reads in one place.
 */
export declare function resolveReportFormat(options: ResolveReportFormatOptions): ReportFormat;
export interface ResolveReportFormatOptions {
    envFormat: ReportFormat | undefined;
    jsonFlag: boolean;
}