In Create agent, describe the reply the caller should get. List the fields, which ones are required, and what each one means. Example: a support reply with a short answer, a confidence, and the source title it used.
The builder puts that contract into the system prompt and shows it before anything is saved. Change the wording in chat until the shape is right. Accept writes the Draft. Discard or leave saves nothing.
An output structure is the reply the agent returns to your application. It is not a place to collect API keys or passwords. Ask for business fields, not credentials.