Spin up a Notion deal room when HubSpot deals advance to late stage

Build me an agent workflow that spins up a Notion deal room and pings the AE in Slack the moment a HubSpot deal advances into a late-stage pipeline phase.

Trigger: a HubSpot outgoing webhook that fires on deal property changes for the deal stage. The agent should only proceed when the new stage is one of my late-stage values (default to Demo Scheduled and Proposal Sent, but make the list configurable). The webhook payload will include the deal id, which is what we key off of.

Once it fires, the agent should:

1. Use HubSpot Get Deal on the deal id to pull deal name, amount, stage, pipeline, close date, and owner. Resolve associated company and primary contact ids.

2. Use HubSpot Get Contact on the primary contact to pull name, title, email, and phone.

3. Research the company on the web. I want a short profile covering rough size, industry, recent news from the last 90 days, and the likely buying motion (bottoms-up vs top-down, who typically owns the budget, etc). Keep it to a few tight paragraphs, not a wall of text.

4. Use Notion Query a Data Source against my Accounts database to see if there is already an account page for this company. If yes, capture its page id so we can link to it. Also Query a Data Source against my Deal Rooms database to check if a page already exists for this deal id; if it does, update that page instead of creating a new one.

5. Use Notion Create a Page in my Deal Rooms database. Set the page title to '<Company> - <Deal Name>'. Set properties for Deal Stage, Amount, Close Date, Deal Owner, HubSpot Deal Id, and a relation to the Accounts page if one was found.

6. Use Notion Append Block Children to populate the page with the following sections, each as a heading_2 followed by content blocks: Company Overview (the web research summary), Key Contacts (primary contact and any other contacts on the deal as a bulleted list with name, title, email), Deal Context (amount, stage, pipeline, owner, close date as a callout or bulleted list), Open Questions (3 to 5 sharp questions the AE should bring into the next conversation, generated from the research and deal data), and Next Steps (an empty checklist the AE can fill in).

7. Use Slack Send a Message to DM the deal owner. The DM should include a link to the new Notion page and a one-paragraph executive summary covering who the company is, what stage the deal is at, what the dollar amount is, and the single sharpest thing the AE should know going into the next conversation. Keep the tone like a peer briefing the AE, not a marketing email.

Make the late-stage trigger list, the Notion Deal Rooms database id, the optional Accounts database id, and the deal owner email mapping configurable. If the deal owner cannot be mapped to a Slack user, fall back to a designated channel and call out the unmapped owner in the message.

The point is to give the AE a real prep doc the moment the deal advances, not a placeholder.