diff --git a/src/index.ts b/src/index.ts
index b12c504d..b435ce52 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -69,13 +69,26 @@ export interface ClientOptions {
   authToken?: string | null;
 }
 
-/** Instantiate the API Client. */
+/** API Client for interfacing with the Anthropic API. */
 export class Anthropic extends Core.APIClient {
   apiKey: string | null;
   authToken?: string | null;
 
   private _options: ClientOptions;
 
+  /**
+   * API Client for interfacing with the Anthropic API.
+   *
+   * @param {string | null} [opts.apiKey=process.env['ANTHROPIC_API_KEY']] - The API Key to send to the API.
+   * @param {string} [opts.baseURL] - Override the default base URL for the API.
+   * @param {number} [opts.timeout=10 minutes] - The maximum amount of time (in milliseconds) the client will wait for a response before timing out.
+   * @param {number} [opts.httpAgent] - An HTTP agent used to manage HTTP(s) connections.
+   * @param {Core.Fetch} [opts.fetch] - Specify a custom `fetch` function implementation.
+   * @param {number} [opts.maxRetries=2] - The maximum number of times the client will retry a request.
+   * @param {Core.Headers} opts.defaultHeaders - Default headers to include with every request to the API.
+   * @param {Core.DefaultQuery} opts.defaultQuery - Default query parameters to include with every request to the API.
+   * @param {string | null} [opts.authToken]
+   */
   constructor({
     apiKey = Core.readEnv('ANTHROPIC_API_KEY') ?? null,
     authToken = Core.readEnv('ANTHROPIC_AUTH_TOKEN') ?? null,