Auto Accept Quests

Auto Accept Quests[]

(Note: An upgraded version of this script with an easy step-by-step setup guide with pictures can be found on this link)

Run hourly, this script will join a quest automatically if the invite is available in your party.

Go to script.google.com. If this is your first script, this will automatically create a new Google script for you and open an editor for it. Otherwise, edit an existing project by clicking the pencil icon next to it, or create another.
Paste the code snippet below into the editor, replacing the spaces marked #HabiticaUserID# and #HabiticaAPIToken# with Habitica User ID and API Token (leave the quotes). These can be found under the API tab in your Habitica settings.

 function scheduleJoinQuest() {
   var habId = "#HabiticaUserID#";
   var habToken = "#HabiticaAPIToken#";
 
   var paramsTemplate = {
     "method" : "get",
     "headers" : {
       "x-api-user" : habId, 
       "x-api-key" : habToken    
     }
   }  
   var response = UrlFetchApp.fetch("https://habitica.com/api/v3/groups/party", paramsTemplate);
   var party = JSON.parse(response);
 
   if ((party.data.quest.key != undefined) && (party.data.quest.active != true) && (party.data.quest.members[habId] == undefined)){
   paramsTemplate = {
       "method" : "post",
       "headers" : {
         "x-api-user" : habId, 
         "x-api-key" : habToken       
       }     
     }
     var params = paramsTemplate;
  
     UrlFetchApp.fetch("https://habitica.com/api/v3/groups/party/quests/accept", params)
   }
 }

OR more clear code below:

const scheduleJoinQuest = () => {
  const habId = '#HabiticaUserID#';
  const habToken = '#HabiticaAPIToken#';
  const partyAPI = 'https://habitica.com/api/v3/groups/party';
  const headers = {
    'x-api-user': habId,
    'x-api-key': habToken,
  };
  const response = UrlFetchApp.fetch(
    partyAPI,
    {
      method: 'get',
      headers
    }
  );
  const { data: { quest } } = JSON.parse(response);

  if (quest.key && !quest.active && !quest.members[habId]) {
    UrlFetchApp.fetch(
      `${partyAPI}/quests/accept`,
      {
        method: 'post',
        headers
      }
    );
  }
}

From the sidebar on the left, select Triggers. Then add a trigger that runs scheduleJoinQuest Time-driven on an Hour timer with the parameter of Every hour.
Save and you're done!