Daily meeting prep brief in Slack at 7am

Build me an agent workflow that delivers a daily meeting prep brief to my Slack DMs every weekday at 7am US Eastern. The trigger should be a cron schedule.

When it runs, the agent should use Google Calendar's List Events to pull every event on my primary calendar for that day (from 00:00 to 23:59 in my timezone). Skip cancelled events and skip any event where every attendee email shares my own email domain, so internal-only meetings don't make it into the brief.

For each remaining meeting, identify the external attendees (anyone not on my domain). For each external attendee:

1. Use HubSpot's Search Contacts to find them by email. If they exist, grab their company and the associated deals, then use HubSpot's Search Deals to pull the most relevant open deal and report its stage, amount, and last activity date.

2. Use Gmail's List Messages with a from/to query for that email address to find the most recent thread, then use Gmail's Get a Message to read the latest message in that thread. Summarize the thread in one or two sentences. Do not paste the full email body.

Then compose a single Slack DM to me using Slack's Send a Message (open a conversation with myself first if needed). Format it as a scannable list of meetings in chronological order. For each meeting include: time, title, external attendee names with company, deal stage and amount when available, a one or two sentence summary of the most recent email thread, and a short "what to focus on" suggestion based on the deal stage and recent context.

If an attendee isn't found in HubSpot, still include the meeting and note that this looks like a net-new contact. If there's no recent email thread, say so instead of inventing context. Keep the whole DM under roughly 2,000 characters so it stays readable on mobile. If I have no external meetings that day, send a short DM saying so rather than skipping the run silently.