Rest API to retrieve a CLOB field is not working

Hello,   I'm working with an API REST integration  and I'm trying a query to retrieve the field description from the activity table but it doesn`t work

In the activity table  the  description field is CLOB 

For example, looking at the image below, I want to retrieve the text :  Buen dia por favor completar el pedido 1-678344588006

CLOB_1.jpgI've tried with this  GET action :"IM00901344" and type="Open"

The response is :

I don't have the description...  please ¿can anybody help me?  Thanks in advance.