It's frustrating when using s3-credentials put-object that you have to specify the key name each time, rather than deriving that from the filename:

s3-credentials put-object simonwillison-cors-allowed-public \
  click_default_group-1.2.2-py3-none-any.whl \
  /tmp/click-default-group/dist/click_default_group-1.2.2-py3-none-any.whl

One way to fix this would be with a s3-credentials put-objects which works like this:

s3-credentials put-objects simonwillison-cors-allowed-public /tmp/click-default-group/dist/click_default_group-1.2.2-py3-none-any.whl

It could accept multiple files (hence the plural name) and could also accept directories and recursively upload their contents.