Personalized prep emails for new Calendly bookings

Build me an agent workflow that sends a personalized prep email to every new Calendly invitee, the moment they book.

Trigger: a Calendly webhook subscription on the invitee.created event for my organization. Every time a new booking comes in, fire the workflow with the webhook payload.

When the workflow fires, do the following:

1. From the webhook payload, grab the scheduled event URI and the invitee URI. Use Calendly's Get Scheduled Event to pull the event start time, end time, event type name, location/conferencing details, and the host. Use Calendly's List Event Invitees (or Get Event Invitee) to pull the invitee's name, email, timezone, and their answers to any custom booking questions.

2. Hand all of that to the agent and ask it to write a short, warm prep email to the attendee. Rules for the email:

- Under 150 words total, plain text, no marketing styling, no emojis, no images. It should read like a one-to-one note from a real person.

- Open by confirming the meeting time, formatted in the attendee's own timezone (from the Calendly invitee record), with the day of week.

- Restate the meeting topic using the attendee's own words from their booking question answers. Quote or paraphrase what they actually wrote, do not invent goals they did not mention.

- Include a one-line agenda derived from those same answers (for example: "I'll walk through X, you tell me about Y, and we'll figure out next steps on Z").

- End with one specific prep question for them to think about before the call, tailored to what they said they wanted to discuss.

- Sign off as me (use my name and a one-line signature, which I'll provide in config).

- If the attendee did not answer any custom questions, fall back to a short prep email keyed off just the event type name and time, without inventing details.

3. Send the email with SendGrid's Send Email operation. From: my verified sender address. To: the invitee's email. Subject: something like "Prep for our {event_type} on {day, time tz}". Body: the plain-text email the agent wrote. Reply-to: my address.

Other requirements:

- Only send for the invitee.created event. Ignore invitee.canceled.

- Skip sending if the booking is less than 30 minutes away (the prep email won't help) and just log it.

- Skip internal teammates: if the invitee email matches my company domain, do not send.

- Make the sender name, sender email, my display name for the sign-off, and the company-domain skip list easy to configure at the top of the workflow so I can tweak them without editing logic.