Missing token for argument within an HTTP request

I am getting an error ‘Missing token for argument’ when incorporating a tag in the middle of an HTTP request and wondering what I’m doing wrong.

When passing the tag to a variable, string or integer it returns 23.5

When I put 23.5 in the HTTP request it works fine.

Do I need some additional brackets or something?

Alternatively is there an easy way to do this in Homeyscript?

TIA

The tag in {{ }} fixed it - spent ages on that, wish I’d tried it haha!