Initially suggested by @SamWilsn here #3096 (comment), but apparently recipe_name() is dynamic, so it can't move the mkdir into a shared recipe.

Here's an idea from an alternative:

[private]
_tmp name:
    @mkdir -p "{{ output_dir }}/{{ name }}/tmp"

json-loader *args: (_tmp "json-loader")
    uv run fill ...

If we bumped min version from 1.43 to 1.53 (which I'd prefer to avoid), I think we could write:

json-loader *args: (_tmp recipe_name())

Originally posted by @danceratopz in #3096 (comment)