Your syntax for variable interpolation is incorrect:

-"${COMPONENT}"
+"\(COMPONENT)"

You actually don't even need interpolation here, because COMPONENT is already a string. So it can just be component = List(COMPONENT).

In case you aren't already, I highly recommend using one of our editor plugins for writing Pkl, because it they will provide feedback about this to you.

Some other notes:

1. List is a data type that's meant for in-language operations (map/flatmap/filter/etc). If you want to describe data, you should use Listing.

2. If your module only makes sense as JSON, you should go ahead and set the output.renderer. Then, you don't need to add -f json anymore as a CLI flag.

   output {
    renderer = new JsonRenderer {}
   }

3. I think it makes more sense to model your inputs as external properties instead of env vars.

   pkl eval -p SERVICE_NAME="1ドル" -p COMPONENT="2ドル" pkl-templates/my-template.pkl

   With this, you'd read("prop:SERVICE_NAME")

4. Instead of using Dynamic, try defining classes for your schema. Dynamic is sort of an escape hatch and has its uses, but generally you wouldn't use it for describing data. Also, try separating your data and schema into different files

   // MySchema.pkl
   Tags: Tags
   class Tags {
    component: Listing<String>
   }
   output {
    renderer = new JsonRenderer {}
   }

   // myData.pkl
   amends "MySchema.pkl"
   tags {
    component {
    read("prop:COMPONENT")
    }
   }