AP approval brief in Slack for new Ramp bills

Build me an AP approval brief workflow anchored on Ramp, with Slack as the approval surface.

Trigger: poll Ramp for new bills. Whenever a new bill arrives, run the agent.

For each new bill, the agent should:

1. Call Ramp Get Bill on the triggering bill ID to fetch full bill detail (amount, currency, line items, due date, memo, vendor ID, entity, attachment links, deep link to the bill in Ramp).

2. Call Ramp Get Vendor on the bill's vendor ID to retrieve vendor name, category, contacts, and bank account info.

3. Call Ramp List Bills filtered to the same vendor for the last 12 months to compute: total YTD spend with this vendor, total spend over the last 12 months, count of past bills, and average invoice size. If there are no prior bills, treat this as a first time vendor.

Then assemble an approver brief covering: vendor name and category; current invoice amount and due date; whether this is a first time vendor; YTD spend with this vendor and 12 month spend; average invoice size and how the current invoice compares (flag if more than 25 percent above the historical average); and a recommended action chosen from: Approve (typical amount, established vendor), Hold for manager review (first time vendor, missing bank info, or amount more than 25 percent above average), or Flag as anomaly (amount more than 100 percent above average, duplicate of a recent bill, or vendor in a sensitive category).

Post the brief to a #bill-approvals Slack channel using Slack Send a Message. Format it cleanly with the vendor name as the headline, the recommendation prominent at the top, the supporting numbers in a compact list, and a direct link back to the bill in Ramp so the approver can review and approve inside Ramp.

Important: do not attempt to approve the bill via the Ramp API. There is no approve bill operation. The workflow stops at producing the brief. Approval happens by a human inside Ramp.

Make the Slack channel, the anomaly threshold (default 25 percent), and the lookback window (default 12 months) easy to change.