Character limit on the comments section of a CTA?

Jessica - 
The destination field "Description" in SF task is a text area and that could hold a whatever is possible in CTA  comments, so what is exactly the issue that you are seeing?

Each morning I'll get a failed report that states that the description field is too long. I've found that this happens when someone pastes an email or lots of page breaks into the comments field. See attached for error received.

Got it! So to avoid this you would like to setup a check saying, trim the # of characters to 160 or some number like that. 

Jessica  - The comments field in CTA can hold upto 131072 characters whereas the Description field in SF task can hold 32000 characters. 
You can solve the issue by either increasing the limit in SF task Description field or decreasing the field size in CTA comments. When you decrease the size of a field you may end up trimming some of the comments, but the good part with Salesforce is it shows how many records are going to get trimmed. 

Thank you, Sundar! How can I decrease the size of the CTA comment field?

Sounds like we are not going the path of trimming the comments section, but I for one do not want to see that happen.  Or, if it's a common use case, then provide admin controls that determine whether or not to limit the size of the field.  

This is something that needs to be done by a salesforce Admin under "Setup" --> Create --> Objects --> Edit "Call To Action" object. under that comments section can be edited and the fields size can be reduced to 32k.

Admin control from Gainsight administration would be an ideal situation here.