export type RawHttpRequestDump = {
    provider: string;
    api: string;
    model: string;
    method?: string;
    url?: string;
    headers?: Record<string, string>;
    body?: unknown;
    diagnostics?: Record<string, unknown>;
};
export type CapturedHttpErrorResponse = {
    status: number;
    headers?: Headers;
    bodyText?: string;
    bodyJson?: unknown;
};
/** Whether `message` (from a 400 response) signals an unavailable/unknown model. */
export declare function isModelUnavailableError(message: string, error: unknown): boolean;
/** Actionable guidance for selecting an available model/provider. */
export declare function formatModelUnavailableGuidance(dump: RawHttpRequestDump | undefined): string;
/** Directory holding the retained HTTP 400 dumps. */
export declare function httpRequestDumpDir(): string;
/**
 * Drop the oldest dumps beyond the cap. Best-effort: diagnostics must never turn
 * a request failure into a second failure, so every step swallows its error.
 *
 * File names are `${Date.now()}-${hash}.json`, so a lexical sort is chronological
 * for the millisecond timestamps this writer produces.
 */
export declare function pruneHttpRequestDumps(dir?: string): Promise<number>;
export declare function appendRawHttpRequestDumpFor400(message: string, error: unknown, dump: RawHttpRequestDump | undefined): Promise<string>;
/**
 * Name the failed connection when the request never produced an HTTP status.
 *
 * Bun raises DNS and socket failures as a bare `Error` whose message is a
 * standalone hint ("Was there a typo in the url or port?", "Unable to connect.
 * Is the computer able to access the url?") while the actionable facts live on
 * `code` and `path`. Those properties are dropped when only `message` reaches
 * the assistant message, so a provider outage, a local DNS failure, and a
 * mistyped custom base URL all render as the same context-free sentence.
 * Appending the code and the target URL tells the user which host failed and
 * whether the fault is theirs.
 */
export declare function appendTransportFailureContext(message: string, error: unknown, rawRequestDump: RawHttpRequestDump | undefined): string;
export declare function finalizeErrorMessage(error: unknown, rawRequestDump: RawHttpRequestDump | undefined, capturedErrorResponse?: CapturedHttpErrorResponse): Promise<string>;
export declare function withHttpStatus(error: unknown, status: number): Error;
/**
 * Rewrite error message for GitHub Copilot request failures.
 * Must run AFTER finalizeErrorMessage since it replaces the message entirely.
 *
 * 400 `model_not_supported` = Copilot routing rollout gap for our OAuth client.
 *        A preview model (gpt-5.3-OpenAI code backend, gpt-5.4*, ...) flaps between 200 and
 *        400 because only some of Copilot's backends have the model. After the
 *        in-request retry exhausts, surface guidance rather than the raw error.
 * 401 = token invalid/expired → credential removal is safe, prompt re-login.
 * 403 = token valid but access denied (plan, model policy, org restriction) →
 *       do NOT reuse the auth-failed string (which triggers credential removal).
 */
export declare function rewriteCopilotError(errorMessage: string, error: unknown, provider: string): string;