In case this helps anyone else:
I was creating an Action to call the YouTube Data API, which expects an API key as a query parameter named “key”. No matter what I tried in the Authentication dialog and/or components securitySchemes in the OpenAPI spec, it never worked.
Finally, I gave up trying to “do it right” and just went ahead and added the key as a parameter, like this:
parameters:
- name: key
in: query
description: API key
required: true
schema:
type: string
enum: [YOUR_API_KEY]
Now, I don’t think I should have to do a workaround like this, but it works while the implementation of the Action is seemingly buggy, so I’ll live with it. Would be nice to get it fixed though.