import type { ToolResultGuardrailContext, ToolResultGuardrailSpec } from '../../types/guardrail/index.js';
import type { ToolResult } from '../../types/tool/index.js';
import type { Logger } from '../../utils/logger.js';
/**
 * A tool result was refused terminally.
 *
 * Thrown rather than returned because the caller's failure path turns every
 * exception into an ordinary tool failure the model then reads and works
 * around — which is exactly what a terminal refusal must not become. The
 * distinct type is what lets that path re-throw this one and convert the
 * rest. A `halt` reported as a failed tool call would be a `refuse` with
 * extra steps.
 */
export declare class ToolResultHalted extends Error {
    readonly guardrail: string;
    constructor(guardrail: string, reason: string);
}
/**
 * Screen a tool's result before anything downstream reads it.
 *
 * Runs every guardrail in order and stops at the first refusal. Rewrites
 * compose — each guardrail sees what the previous one produced — matching
 * the output-guardrail path, so a redaction chain behaves the same at both
 * boundaries.
 *
 * Returns the result to use. A refusal comes back as a failed `ToolResult`
 * carrying the reason, because that is the shape the model already knows
 * how to read: it is the same thing a tool that could not do its job
 * returns, and the alternative — a blank result — tells the model the tool
 * found nothing, which is a different claim and a false one.
 */
export declare function screenToolResult(guardrails: readonly ToolResultGuardrailSpec[] | undefined, result: ToolResult, ctx: Omit<ToolResultGuardrailContext, 'output' | 'success'>, log: Logger): Promise<ToolResult>;
//# sourceMappingURL=screen.d.ts.map