/**
 * Resolve the base URL for ChatGPT account-API requests (`wham/usage`,
 * `wham/rate-limit-reset-credits`).
 *
 * These endpoints live on the canonical ChatGPT origin and authenticate with
 * the Codex OAuth bearer minted for that origin. They are NOT part of the
 * `/responses` API surface that streaming proxies (Headroom, 9router, etc.)
 * forward, so a `providers.openai-codex.baseUrl` override pointed at such a
 * proxy MUST NOT be used here — doing so 404s and silently breaks
 * `/usage show` (issue #3679).
 *
 * Accepted overrides are the canonical `chatgpt.com` / `chat.openai.com`
 * origins. Any extra path (e.g. a streaming override like
 * `/backend-api/codex/responses`) is normalized to `${origin}/backend-api`,
 * since the account endpoints always live directly under `/backend-api`. Any
 * other host falls back to {@link CODEX_BASE_URL}.
 */
export declare function normalizeCodexBaseUrl(baseUrl?: string): string;