A live preview writes every AI message in the sequence for a lead, exactly as it would go out, without sending anything. Use it before you switch a sequence on, and again every time you change a prompt or a skill file.

Generate a live preview

Open the agent's Leads tab and tick one or more leads.
Click Preview in the bar at the bottom.
Generate a live preview? shows how many leads and messages will be written. It writes every AI message in the sequence for the selected leads and runs any enrichment they still need, so credits might be consumed. Nothing is sent: the drafts are yours to review.
Click Yes, generate. Vetta shows its progress ("Working on 1 lead"), then opens the preview.

Review the drafts

The preview has three columns:

Previewing: the leads in this preview, and the credits used.
The drafts: every message step for the selected lead, with its subject and body, in order. "Drafts only, nothing has been sent."
Sequence: the agent's sequence, step by step, including conditions and their paths. Click a step to preview just that message; Show all steps goes back to all of them.

Each draft has an Edit button if you want to change one message for this lead by hand. Looks good closes the preview.

Regenerate after a change

When a draft is not right, change what the AI follows, not the draft:

Edit the skill file (Tuning AI messages with skill files) or the variable's prompt (Setting up AI variables).
Back in the agent's Leads tab, tick the same lead and click Preview.
The lead already has messages, so Show messages opens them without writing or charging anything.
Click Regenerate. Vetta rebuilds every draft with the updated skill file and prompt.
Read the new drafts against the old ones. Repeat until they read right, then preview two or three other leads to make sure the change works beyond one person.

Key outcome

Previewing turns AI messages from a leap of faith into something you sign off. A few minutes of preview and regenerate after each change is what keeps an agent's outreach on-voice as it scales.