export type DetectedVendor = 'claude-code' | 'codex' | 'copilot' | 'unknown';
export interface RuntimeDetectorOptions {
    /** Override for env (used by tests). */
    readonly env?: NodeJS.ProcessEnv;
    /** Override for home directory (used by tests). */
    readonly home?: string;
}
export interface DetectionResult {
    readonly vendor: DetectedVendor;
    /** Why this vendor was chosen — useful for diagnostics and tests. */
    readonly reason: string;
}
/** Detect the active vendor. Order: claude-code → codex → copilot →
 *  unknown. The first match wins. */
export declare function detectRuntime(opts?: RuntimeDetectorOptions): DetectionResult;