Two escape hatches
Outbound webhooks notify your backend when appointments are created or changed. Custom HTTP tools let the agent call your API mid-conversation—fee schedules, inventory, ticket status.
Don’t skip verification
Validate signatures. Use staging URLs first. Return small JSON from tools; dumping a 500-line payload into a voice turn goes poorly.
When to prefer native connectors
If you live in HubSpot or Zoho and the field mapping fits, use the connector. Webhooks are for odd systems and composite workflows—not for avoiding setup.