Can an agent see which customers were already contacted in order to avoid reaching out to the same customer twice?

However, businesses should choose the data retention period related to contacts and conversations shown on the Conversations Inbox. By default, the data retention period is 90 days, but this can be tailored to your needs. 

In addition, to make sure agents have the background needed about customers, your company can integrate the Conversations Inbox with your CRM system. That means you can retrieve information from the Conversations Inbox to your CRM - and vice-versa - making sure relevant customer data is synched appropriately.