I'm trying to create an interaction widget in Purecloud but I can't find any documentation. the only info I've been able to find is this page which has a blueprint for one.
What I'm trying to figure out is what URL params are available. I see he has pcEnvironment and pcConversationId. I know there are others available is this documented somewhere? And how can my widget auth as the agent?
Interaction Widgets are just one form of what Genesys calls a Client App, which is documented here: https://developer.genesys.cloud/platform/integrations/client-apps/. If you scroll to the "URL Interpolation" topic you'll see the various query parameters that can be passed in for each type of Client App.
To make things really easy on yourself I'd recommend using one of our Platform SDK language wrappers. For instance, if you are programming in Javascript then you can use this SDK: https://developer.genesys.cloud/devapps/sdk/javascript that will handle authentication, managing auth tokens, and providing API method calls.