what can account holders see?

The only thing that is available is the usage report. Usage reports record phone numbers for text/calls and with time date, length of calls. And the amount of data usage.   Nothing else. 

Text and data content is private at&t does not have that information and it is not on the usage report

Just to be clear, they can not view anything about messages on the apps you mention. Messages over those apps are just data, they are not in the message log.

Hi dancingflame! We are here to help with your inquiry regarding who is able to see your texts messages from apps like discord, messenger, tumblr and vent!

The account holder is only able to see regular text message usage as formerlyknownas & sandblaster stated. The account holder is not able to see the details of the text message as AT&T values your privacy and does not store message details. Learn more about AT&T Secure Family App, which is used to locate family members, control their smartphone screen time, block apps and websites, and more. This app cannot be used to check the content of the children's messages. 

We hope this helps! Thank you for reaching out to the AT&T Community Forums!

Rhoda, AT&T Community Specialist 

so can an account holder see what the people on their plan is saying? or what the people are saying to them?

@jayboopp Presuming you are talking about texts, no. The account holder can not see anyone’s texts.

@jayboopp

The previous replies answered this question - if you read them.

Text and data content is private at&t does not have that information and it is not on the usage report

The account holder is not able to see the details of the text message

Can the plan holder get into the att cloud 

@Dawn7879

Read the solution post, which answers what they can see...

Nothing else. 

I believe this should be private as well!  My bf thinks I’m cheating when I text and call my family.  And abuses me because of it.  You have no right to show him this. @ATTHelp 

Wow ATT not answer this smh