Trigger
Schedule trigger. Both agents share Grok 4.1 Fast (OpenRouter) and a Calculator tool for precision math.
Agent 1 — Last Reminder
Reads all invoices (getData tool), filters Unpaid status, composes a manager digest email, sends via Gmail, then updates the Last Reminder column for every affected row one by one.
Agent 2 — Penalty Calculator
Applies tiered rules: 0.05%/day (1–7 days), 0.1%/day (8–30 days), 0.15%/day (31+ days). Uses Calculator for rounding. Writes Days Overdue, Penalty Rate, Penalty Amount, and Total Amount per invoice.
Tools
OpenRouter (Grok 4.1)Google SheetsGmailCalculator
Flow
01Schedule
→
02Agent 1: getData
→
03Filter unpaid
→
04Send digest email
→
05updateLastReminder ×n
→
06Agent 2: getData
→
07Calculate penalties
→
08updatePenalty ×n
Key concepts
Tool-calling agents, agent chaining, fromAI() overrides, Sheets as data source + output, tiered logic in system prompts.