It appears one can only enter one string of text to set the headers of an HTTP action. What do we need to separate the headers with to set multiple headers?
Headers are formatted as name:value separated by newlines as documented in the HTTP RFC: RFC 2616 - Hypertext Transfer Protocol -- HTTP/1.1
The alloy web client will not let you enter newlines in string attributes, so you will need to use the API directly to set your headers.