diff --git a/packages/authentication-client/src/core.ts b/packages/authentication-client/src/core.ts
index 07db6190f4..61e1211847 100644
--- a/packages/authentication-client/src/core.ts
+++ b/packages/authentication-client/src/core.ts
@@ -82,6 +82,13 @@ export class AuthenticationClient {
     })
   }
 
+  /**
+   * Parse the access token or authentication error from the window location hash. Will remove it from the hash
+   * if found.
+   *
+   * @param location The window location
+   * @returns The access token if available, will throw an error if found, otherwise null
+   */
   getFromLocation(location: Location) {
     const [accessToken, tokenRegex] = getMatch(location, this.options.locationKey)
 
@@ -102,10 +109,21 @@ export class AuthenticationClient {
     return Promise.resolve(null)
   }
 
+  /**
+   * Set the access token in storage.
+   *
+   * @param accessToken The access token to set
+   * @returns
+   */
   setAccessToken(accessToken: string) {
     return this.storage.setItem(this.options.storageKey, accessToken)
   }
 
+  /**
+   * Returns the access token from storage or the window location hash.
+   *
+   * @returns The access token from storage or location hash
+   */
   getAccessToken(): Promise<string | null> {
     return this.storage.getItem(this.options.storageKey).then((accessToken: string) => {
       if (!accessToken && typeof window !== 'undefined' && window.location) {
@@ -116,10 +134,19 @@ export class AuthenticationClient {
     })
   }
 
+  /**
+   * Remove the access token from storage
+   * @returns The removed access token
+   */
   removeAccessToken() {
     return this.storage.removeItem(this.options.storageKey)
   }
 
+  /**
+   * Reset the internal authentication state. Usually not necessary to call directly.
+   *
+   * @returns null
+   */
   reset() {
     this.app.set('authentication', null)
     this.authenticated = false
@@ -128,7 +155,9 @@ export class AuthenticationClient {
   }
 
   handleError(error: FeathersError, type: 'authenticate' | 'logout') {
-    if (error.code === 401 || error.code === 403) {
+    // For NotAuthenticated, PaymentError, Forbidden, NotFound, MethodNotAllowed, NotAcceptable
+    // errors, remove the access token
+    if (error.code > 400 && error.code < 408) {
       const promise = this.removeAccessToken().then(() => this.reset())
 
       return type === 'logout' ? promise : promise.then(() => Promise.reject(error))
@@ -137,6 +166,14 @@ export class AuthenticationClient {
     return Promise.reject(error)
   }
 
+  /**
+   * Try to reauthenticate using the token from storage. Will do nothing if already authenticated unless
+   * `force` is true.
+   *
+   * @param force force reauthentication with the server
+   * @param strategy The name of the strategy to use. Defaults to `options.jwtStrategy`
+   * @returns The reauthentication result
+   */
   reAuthenticate(force = false, strategy?: string): Promise<AuthenticationResult> {
     // Either returns the authentication state or
     // tries to re-authenticate with the stored JWT and strategy
@@ -159,6 +196,13 @@ export class AuthenticationClient {
     return authPromise
   }
 
+  /**
+   * Authenticate using a specific strategy and data.
+   *
+   * @param authentication The authentication data
+   * @param params Additional parameters
+   * @returns The authentication result
+   */
   authenticate(authentication?: AuthenticationRequest, params?: Params): Promise<AuthenticationResult> {
     if (!authentication) {
       return this.reAuthenticate()
@@ -182,6 +226,12 @@ export class AuthenticationClient {
     return promise
   }
 
+  /**
+   * Log out the current user and remove their token. Will do nothing
+   * if not authenticated.
+   *
+   * @returns The log out result.
+   */
   logout(): Promise<AuthenticationResult | null> {
     return Promise.resolve(this.app.get('authentication'))
       .then(() =>