Use stdin and arguments in a template #26

Is it possible define the exact placement of stdin and arguments when defining a template? From the docs it's not immediately obvious to me what $input is when I have both std and arguments.

context: I'm trying to create an llm template that I can use with Helix editor's :pipe feature. I want the stdin to be the selected text from the editor and then have a prompt like:

Transform the provided code according to the following instruction: $arguments

Output only the modified code with no explanations, comments, or surrounding text.

Code:

$stdin

Start with the template documentation and the CLI handling used when stdin and arguments are passed, then trace how the Helix editor's :pipe use case reaches template expansion. The work is done when a template can place stdin and arguments exactly as requested and the documentation clearly explains the relevant variables and behavior.