diff --git a/src/source/client/base.js b/src/source/client/base.js
index 4abcd4b3..9356eadf 100644
--- a/src/source/client/base.js
+++ b/src/source/client/base.js
@@ -37,7 +37,8 @@ export class BaseClient {
 
   /**
    * Send a request with the options
-   * @param {object} [options]
+   * @param {{headers: HeadersInit, credentials: RequestCredentials, signal: AbortSignal}} [options={}]
+   * @returns {Promise<BaseResponse>}
    */
   async request({ headers, credentials, signal } = {}) { // eslint-disable-line no-unused-vars
     throw new Error('request is not implemented');
diff --git a/src/source/client/fetch.js b/src/source/client/fetch.js
index 096c7b20..d7bd1b4a 100644
--- a/src/source/client/fetch.js
+++ b/src/source/client/fetch.js
@@ -32,6 +32,10 @@ export class FetchClient extends BaseClient {
     this.credentials = credentials;
   }
 
+  /**
+   * @param {{headers: HeadersInit, credentials: RequestCredentials, signal: AbortSignal}} [options={}]
+   * @returns {Promise<FetchResponse>}
+   */
   async request({ headers, credentials, signal } = {}) {
     const response = await fetch(this.url, {
       headers, credentials, signal,