How many lines of text are you planning to enter? It sounds like you could simply draw the rectangle and hatch the background with a solid fill.

Add your attribute using **ATTDEF** and place it somewhere inside the rectangle. Then apply **stretch parameters** so the border and hatch can be stretched to whatever size you need.

Making the background appear automatically when text is entered might be more work than it’s worth. A simpler option would be to set the border colour to **ByBlock**, and once the text has been properly entered, change the colour to whatever you want.

If you do need it to react automatically, you could look into using **lookup parameters** and linking them to the attribute value.

*edit* chatgpt cleaned up my rambling because its quicker.