/**
 * DetectionBackend - Pluggable detection classifier
 *
 * Allows users to plug in ML-based detection alongside the built-in regex guards.
 * Default: regex-only (zero dependencies, <5ms).
 * Optional: any async classifier (embedding similarity, external API, custom ML).
 *
 * Why this exists: Research shows regex-only detection is bypassed at >90% ASR
 * by adaptive attacks (JBFuzz 99%, AutoDAN 88%, PAIR adaptive). This interface
 * lets users add ML-based detection without forcing dependencies on all users.
 */
/** Context about what is being classified */
export interface DetectionContext {
    type: "user_input" | "tool_result" | "llm_output" | "system_context" | "rag_document";
    sessionId?: string;
    metadata?: Record<string, any>;
}
/** Result from a detection classifier */
export interface DetectionResult {
    safe: boolean;
    confidence: number;
    threats: DetectionThreat[];
}
export interface DetectionThreat {
    category: string;
    severity: "low" | "medium" | "high" | "critical";
    description: string;
}
/**
 * Detection classifier callback type.
 *
 * Can be sync (for regex/local ML) or async (for API calls).
 * Users implement this as a function, closure, or class method.
 *
 * @example
 * // Sync classifier (fast, local)
 * const myClassifier: DetectionClassifier = (input, ctx) => ({
 *   safe: !input.includes("hack"),
 *   confidence: 0.9,
 *   threats: []
 * });
 *
 * @example
 * // Async classifier (ML API)
 * const mlClassifier: DetectionClassifier = async (input, ctx) => {
 *   const res = await fetch('https://my-ml-api/classify', {
 *     method: 'POST',
 *     body: JSON.stringify({ text: input, type: ctx.type })
 *   });
 *   const data = await res.json();
 *   return { safe: data.score < 0.5, confidence: data.score, threats: data.threats };
 * };
 */
export type DetectionClassifier = (input: string, context: DetectionContext) => DetectionResult | Promise<DetectionResult>;
/**
 * Create a built-in regex classifier that wraps InputSanitizer + EncodingDetector.
 *
 * Useful as a baseline or fallback classifier.
 */
export declare function createRegexClassifier(config?: {
    threshold?: number;
    detectPAP?: boolean;
}): DetectionClassifier;
/**
 * Merge two detection results (used when combining regex + ML backends)
 *
 * Policy: if EITHER result is unsafe, the merged result is unsafe.
 * Confidence: take the lower confidence (most conservative).
 */
export declare function mergeDetectionResults(a: DetectionResult, b: DetectionResult): DetectionResult;