YetiConnect requires read access to HubSpot Contacts, Companies, Deals, and Lists so reps see full customer context inside the integration and can queue contacts into outbound dialer lists by HubSpot list membership. Write access to Contacts is required because YetiConnect creates and updates contact records when SMS conversations occur with new or unidentified phone numbers, and writes custom messaging properties (yeti_contact_id, opt-in status, last SMS date) on existing contacts. Conversations and custom_channels read/write registers YetiConnect as a custom messaging channel inside the HubSpot Conversations Inbox so reps can send and receive SMS directly from HubSpot's native UI. Files access supports MMS attachments. Owners read enables conversation assignment to the correct rep. Schema read provides custom property metadata during onboarding to map fields. Automation provides custom workflow actions ("Send SMS", "Add to dialer queue") that customers configure inside HubSpot workflows. OAuth supports app installation and token refresh.