You are helping me build the following AI agent workflow.

## Goal
Assignee Payroll Calculations: Scans completed tasks for billable hours, calculates pay using stored hourly rates, and updates a Google Sheet with final amounts.

## Specification
- What it does: You get paid accurately for every completed task as this agent scans your logs, cross-references your hourly rates in Google Sheets, and automatically updates your final amounts without manual calculation.
- Trigger: On a schedule (Scheduled · weekly)
- Autonomy: Fully hands-off
- Expected setup effort: about an afternoon
- Tools/services involved:
  - Dart: Time tracking and task data source
  - Google Sheets: Storing assignee rates and payroll results
  - Code: Processing logic and calculations
  - Google Gemini Chat Model: AI time tracking and assignee scanning

## Known pitfalls, handle each one explicitly in your implementation
1. Rate changes mid-cycle can skew calculations so lock rates at the start of each payroll period.
2. Ambiguous task descriptions may lead to incorrect hour extraction so add validation steps in the code layer.
3. Google Sheets API quotas can be exceeded by large batches so implement chunked writes for updates.

## Reference implementation
https://n8n.io/workflows/11257 (workflow template)
Fetch and inspect this before building. If it matches my stack, adapt it;
if not, rebuild the pattern with my tools.

## Process requirements
1. Before building: ask me which of the listed tools I actually use and
   what my platform is (n8n / Make / code / other). Do not assume.
2. Adapt the pattern to my answers; do not force the reference stack.
3. Address every pitfall above; tell me how you handled each.
4. Provide a test plan I can run before letting this touch real data.
5. Ask before any step that sends messages, modifies data, or spends money.

Source: https://usecasesforagents.com/use-case/automate-assignee-payroll-calculations/ via usecasesforagents.com