Check out the docstring of variable `org-capture-templates`.
There is a doc like this:
```
%\1 ... %\N Insert the text entered at the nth %^{prompt}, where N
              is a number, starting from 1.
```
Maybe this is what you want?

[stardiviner]           <Hack this world!>      GPG key ID: 47C32433
IRC(freeenode): stardiviner                     Twitter:  @numbchild
Key fingerprint = 9BAA 92BC CDDD B9EF 3B36  CB99 B8C4 B8E5 47C3 2433
Blog: http://stardiviner.github.io/

On Fri, Jun 30, 2017 at 5:14 PM, Jean-Christophe Helary <
jean.christophe.helary@gmail.com> wrote:

> I'm looking for a way to use the string acquired by prompt in a second
> location in the template, like:
>
> * TODO %^{prompt} [/] :sometag:\n** TODO (value of ^{prompt} comes here)
> :someothertag:\n
>
> What's the best way to get that "value of ^{prompt}" ?
>
> Jean-Christophe
>