/**
 * @fileoverview Permissive reader for the top-level `schemaVersion:`
 * field of opensip-tools.config.yml + a compatibility classifier.
 *
 * The CLI's pre-action-hook calls these BEFORE any tool's strict loader
 * runs, so the reader must tolerate every "couldn't determine" case
 * (missing file, malformed YAML, missing field, non-integer field) and
 * treat them all as v1. Forward compat for existing user configs
 * written before the field existed.
 *
 * Lives in `core/lib/` alongside `paths.ts` because version detection
 * is a kernel-level concern; every tool's loader benefits.
 */
/**
 * The schema version this CLI binary knows how to load. Bumped when
 * the project config structure changes in a way that requires
 * migration.
 */
export declare const CLI_SUPPORTED_SCHEMA_VERSION: 1;
/** Outcome of `checkSchemaCompat`. */
export type SchemaCompat = {
    readonly kind: 'ok';
    readonly configVersion: number;
} | {
    readonly kind: 'older';
    readonly configVersion: number;
    readonly cliVersion: number;
} | {
    readonly kind: 'cli-too-old';
    readonly configVersion: number;
    readonly cliVersion: number;
};
/**
 * Read the top-level `schemaVersion:` field. Returns 1 for any
 * "couldn't read it" outcome, by design.
 */
export declare function readConfigSchemaVersion(configPath: string): number;
/**
 * Classify a config's declared version against the CLI's supported version.
 *
 *  - 'ok'           — versions match; proceed silently.
 *  - 'older'        — config is older than CLI; CLI can read it (today).
 *                     Future: `opensip-tools migrate` updates it. For
 *                     now the CLI runs it as-is.
 *  - 'cli-too-old'  — config is newer than CLI knows. CLI cannot safely
 *                     load it. User must upgrade the CLI.
 */
export declare function checkSchemaCompat(configVersion: number): SchemaCompat;
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