type FetchLike = (input: RequestInfo | URL, init?: RequestInit | BunFetchRequestInit) => Promise<Response>;
export type OAuth2ClientCredentialsConfig = {
    /** Token endpoint that issues client-credentials grants. */
    tokenUrl: string;
    clientId: string;
    clientSecret: string;
    /** Space-joined scopes (or array). */
    scope?: string | string[];
    /** Optional audience parameter (Auth0, etc.). */
    audience?: string;
    /** Where to send credentials: request body (default) or HTTP Basic header. */
    authStyle?: "body" | "basic";
    /** Extra params merged into the token request body. */
    extraParams?: Record<string, string>;
    /** Refresh this many ms before the token actually expires. Defaults to 60s. */
    expirySkewMs?: number;
    /** Fallback lifetime when the response omits expires_in. Defaults to 3600s. */
    fallbackTtlSeconds?: number;
    fetch?: FetchLike;
    now?: () => number;
};
/**
 * Builds a `tokenSource` for `openai()` / `openaiCompatible()` that performs the
 * OAuth2 client-credentials flow against custom LLM gateways (Azure AD, Auth0,
 * enterprise proxies). Caches the access token in memory and refreshes it
 * automatically before expiry. Returns `() => Promise<string>`.
 */
export declare const createOAuth2ClientCredentialsTokenSource: (config: OAuth2ClientCredentialsConfig) => (() => Promise<string>);
export {};