/**
 * OutputSchemaGuard
 *
 * Validates LLM structured outputs (JSON, function calls) before they
 * reach downstream systems (databases, APIs, UIs).
 *
 * Addresses OWASP LLM05: Improper Output Handling.
 *
 * Why: LLMs can produce structured outputs containing:
 * - Unexpected actions ("delete_all" instead of "search")
 * - Injection in JSON values flowing to downstream parsers
 * - Hallucinated function calls that don't match available tools
 * - Hidden instructions in field values for downstream systems
 */
export interface OutputSchemaGuardConfig {
    /** Expected output schemas keyed by action/function name */
    schemas?: Record<string, OutputSchema>;
    /** Scan all string values for injection patterns (default: true) */
    scanForInjection?: boolean;
    /** Reject outputs with fields not in schema (default: false) */
    strictSchema?: boolean;
    /** Max output size in characters (default: 100000) */
    maxOutputSize?: number;
}
export interface OutputSchema {
    type: "object" | "array" | "string";
    properties?: Record<string, {
        type: string;
        enum?: string[];
        maxLength?: number;
    }>;
    required?: string[];
}
export interface OutputSchemaResult {
    allowed: boolean;
    reason?: string;
    violations: string[];
    schema_valid: boolean;
    injection_found: boolean;
    threats: Array<{
        field: string;
        type: string;
        detail: string;
    }>;
}
export declare class OutputSchemaGuard {
    private config;
    constructor(config?: OutputSchemaGuardConfig);
    /**
     * Validate LLM structured output
     */
    validate(output: any, schemaName?: string, requestId?: string): OutputSchemaResult;
    /**
     * Validate a function/tool call output from LLM
     */
    validateFunctionCall(functionName: string, args: Record<string, any>, requestId?: string): OutputSchemaResult;
    /**
     * Register a schema for an action/function
     */
    registerSchema(name: string, schema: OutputSchema): void;
    private validateAgainstSchema;
    private scanForInjection;
    private safeStringify;
}