Kick off client onboarding when a HubSpot deal closes won

Build me an agent-based workflow that kicks off customer onboarding the second a HubSpot deal moves to closed won, so my CS team stops doing the same 45 minutes of setup by hand on every deal.

Trigger: an incoming webhook from HubSpot fired when a deal's stage changes to closed won. The payload will include the deal ID. I'll configure the HubSpot workflow/subscription on my side; the workflow just needs to accept the webhook and read the deal ID off it.

What the agent should do, in order:

1. Pull deal context from HubSpot. Use Get Deal on the deal ID with associations expanded so we also have the associated primary contact ID and company ID. Then call Get Contact and Get Company to fetch the full records. The agent should end up with: deal name, amount, close date, product/line items, owner; primary contact first name, last name, email, job title; company name, domain, industry, size.

2. Create the onboarding plan on monday.com. On a designated onboarding board (board ID provided at setup), call Create Group with the group title set to the customer's company name. Then call Create Item five times in that new group, one for each milestone: "Kickoff call", "Account provisioning", "Integration setup", "Success plan", "30-day review".

3. Fill in each milestone's columns. For every item created, call Change Multiple Column Values to set owner (default to the deal owner from HubSpot, mapped to the matching monday user), due date (stagger them: kickoff +3 business days from close, provisioning +5, integrations +14, success plan +21, 30-day review +30), and priority. The agent should pick priority and adjust the milestone list intelligently based on deal context: bigger deals (use a threshold like $50k ARR) get High priority and an added "Executive sponsor sync" item; small SMB deals can drop "Executive sponsor sync" and keep priority at Medium; if the product purchased doesn't include integrations, skip or downgrade the "Integration setup" item. Treat the five milestones as a starting template, not a fixed script.

4. Draft the welcome email. Call Gmail Create a Draft addressed to the primary contact's email, from the deal owner's mailbox if possible. The subject should reference the company name and product (for example "Welcome to <Product>, <Company> team"). The body should be warm but concise, reference what they actually bought, name the CSM, summarize the kickoff plan (the five-ish milestones with rough timing), propose two kickoff call windows in the next week, and include a link placeholder for the monday.com group. Tone should adapt to the deal: enterprise deals lean formal and emphasize executive alignment; SMB/self-serve deals lean casual and emphasize time-to-value. Save it as a draft, do not send. The CSM reviews and hits send.

Setup inputs the agent should expect: the monday.com onboarding board ID, the monday column IDs for owner / date / priority (or let the agent introspect the board), a mapping from HubSpot deal owners to monday user IDs and Gmail sender addresses, and the ARR threshold for "enterprise vs SMB" treatment. Default the threshold to $50,000 if not provided.

Error handling: if HubSpot returns no associated contact or company, still create the monday group using the deal name, skip the Gmail draft step, and surface a clear warning. If the monday board ID is invalid, fail loudly before doing anything else so we don't half-onboard a customer.