/**
 * Bot-wall / CAPTCHA classification (#86).
 *
 * Promoted from the cohort's per-MCP duplicates: zillow-mcp's
 * PerimeterX detection (#91) and compass's confirmed AWS-WAF block.
 * Every portal MCP sees responses that may be a bot-wall interstitial
 * rather than real content, and misclassifying one as "not found" is
 * the silent-data-corruption failure class rounds 2-3 stamped out. A
 * shared classifier keeps detection in one place so no MCP reinvents it.
 *
 * Detection keys on the response BODY primarily — a PerimeterX
 * interstitial can be served as HTTP 200 (zillow #91), so requiring a
 * 4xx would miss it — with status and headers as additional signal for
 * vendors (AWS WAF) that only block with a 403.
 *
 * Pure: no I/O, no logging. The caller decides what to do with a
 * positive result (typically: back off via {@link backoffDelayMs} and
 * retry, surfacing the {@link FetchErrorKind} `'bot_challenge'`).
 */
/** Bot-wall vendor a positive classification attributes the block to. */
export type BotWallVendor = 'perimeterx' | 'aws_waf' | 'cloudflare' | 'datadome' | 'unknown';
/**
 * Discriminated result of {@link classifyBotWall}. `blocked: false`
 * carries no vendor; a positive result always names a vendor (falling
 * back to `'unknown'` only if a future arm detects a wall it can't
 * attribute).
 */
export type BotWallResult = {
    blocked: true;
    vendor: BotWallVendor;
} | {
    blocked: false;
};
/**
 * Classify a response as a bot-wall interstitial or genuine content.
 *
 * Detection is body-first (so a 200-status PerimeterX wall is caught),
 * with status/headers as additional signal for vendors that only block
 * with a 403. Arms are ordered most-specific first: PerimeterX (the
 * strongest, body-keyed signal) wins over a generic header.
 *
 * A plain 403 with no bot-wall markers stays `blocked: false` — it's a
 * hard auth error, not a transient wall, and callers must not back off
 * on it.
 *
 * @param body     Response body text.
 * @param status   HTTP status code.
 * @param headers  Optional response headers (case-insensitive lookup).
 */
export declare function classifyBotWall(body: string, status: number, headers?: Record<string, string>): BotWallResult;