Authentication Provider docs

Author: evantahler

pages/home/glossary.mdx

@@ -94,7 +94,20 @@ Monthly Active Users are the unique end-users (counted by `user_id`) who have ex
 
 ### Authentication Starts (Auth Starts)
 
-Authentication Starts are the number of unique users (by `user_id`) who have started the authentication flow for a specific toolkit.  This is a proxy for the number of new users who are using your agent.  The same user authenticating to multiple toolkits will be counted multiple times (e.g. once for Slack and once for Google).
+Authentication Starts are the number of unique users (by `user_id`) who have started the authentication flow for a  authentication provider.  This is intended to be a proxy for the number of new users who are using your agent.  The same user authenticating to multiple toolkits will be counted multiple times (e.g. once for Slack and once for Google).  We also count the act of elevating permissions to a user who has already authenticated to a toolkit (e.g. adding a "write" scope when they previously only had a "read" scope).
+
+### Authentication Provider
+
+An 'authentication provider' is a service that your users can authenticate to grant the agent access to their data or to take actions on their behalf.  This can be a hosted service provider like Google or Slack, or it can be a custom OAuth provider.  Multiple Toolkits may share the same authentication provider (e.g. Gmail and Google Drive share the same Google OAuth authentication provider).  Custom authentication providers are defined in the Arcade Dashboard or your Engine YAML if self-hosting.
+
+*Learn more about [authentication providers](/home/auth-providers).*
+
+### Authentication Scope
+
+An 'authentication scope' is a permission that a user can grant to an agent.  This is used to control what the agent can do with the user's data.  Available authentication scopes are defined by the authentication provider, and each tool defines the scopes it requires.
+
+Learn more about [authorized tool calling](/home/auth/auth-tool-calling).
+
 
 ### Tool Executions