/**
 * Token-level analysis for prompt injection detection.
 * Examines statistical properties of input tokens to flag anomalies.
 * Zero dependencies — pure TypeScript.
 */
import type { Severity } from "./types.js";
export type TokenFinding = {
    type: string;
    message: string;
    severity: Severity;
    evidence: string;
    offset: number;
};
export type TokenAnalysis = {
    totalTokens: number;
    uniqueTokens: number;
    avgTokenLength: number;
    specialCharRatio: number;
    uppercaseRatio: number;
    suspiciousTokenDensity: number;
    findings: TokenFinding[];
};
/**
 * Analyze tokens in the input string for statistical anomalies
 * and suspicious patterns that may indicate prompt injection.
 */
export declare function analyzeTokens(input: string): TokenAnalysis;