import type { ClassifierConfig } from "./types";
export type PromptInjectionClassifierRunner = {
    predictProbability(text: string, options?: {
        signal?: AbortSignal;
    }): Promise<number>;
};
export declare const DEFAULT_MODEL_PATH: string;
/**
 * Initialise the global tokenizer vocabulary from a JSON file.
 * Expected format: { "token": id, ... } — standard HuggingFace vocab.json.
 *
 * Call this once at startup before the first classification call.
 * If never called, the classifier uses character-level fallback tokenization.
 */
/**
 * Returns the token IDs for a pre-tokenized text using the configured strategy:
 *   1. WordPiece (if a vocabulary was loaded via loadClassifierVocabulary)
 *   2. Character fallback (deterministic, no hash collisions)
 */
export declare function tokenizerStrategy(): "wordpiece" | "char-fallback";
export declare function loadClassifierVocabulary(vocabPath: string): boolean;
export declare class OnnxPromptInjectionClassifier implements PromptInjectionClassifierRunner {
    private readonly modelPath;
    private readonly lazySession;
    private initError;
    private initialized;
    private readonly ownTokenizerLabel;
    constructor(config?: ClassifierConfig);
    private initialize;
    /**
     * Returns whether the ONNX model loaded successfully.
     */
    isAvailable(): boolean;
    getInitializationError(): Error | null;
    /**
     * Describes which tokenizer is active so callers can warn if
     * the character fallback is being used in production.
     */
    getTokenizerInfo(): {
        strategy: string;
        vocabSource: string;
        modelPath: string;
    };
    predictProbability(text: string, options?: {
        signal?: AbortSignal;
    }): Promise<number>;
}
export declare function extractClassifierInputText(body: unknown): string;
/**
 * Classifier that combines heuristic signal detection into a calibrated
 * probability score. Implements the same interface as the ONNX classifier
 * so it slots in as a drop-in replacement when the ONNX model is unavailable.
 */
export declare class HeuristicClassifier implements PromptInjectionClassifierRunner {
    predictProbability(text: string): Promise<number>;
}