You are helping me build the following AI agent workflow.

## Goal
Sentiment Analytics Visualizer: Fetches customer reviews from a sheet, classifies sentiment with GPT-4o-mini, and emails a doughnut chart summary to the team.

## Specification
- What it does: You get instant clarity on customer feedback as this agent pulls reviews from your Google Sheet, classifies each one with GPT-4o-mini, and updates the sheet with results. It then generates a visual doughnut chart summary and emails it to your team so everyone stays informed without manual tracking.
- Trigger: Run manually (Manual · on demand)
- Autonomy: Fully hands-off
- Expected setup effort: about an afternoon
- Tools/services involved:
  - Google Sheets: Store and update customer reviews
  - OpenAI Chat Model: Classify review sentiment
  - QuickChart: Generate doughnut chart image
  - Gmail: Email the sentiment chart to recipients

## Known pitfalls, handle each one explicitly in your implementation
1. Inconsistent LLM outputs will break the tallying code, enforce strict JSON or string-only responses in your prompt.
2. QuickChart URLs have length restrictions for large datasets, limit the chart data to aggregated counts rather than individual reviews.
3. Gmail attachments may exceed size limits if not handled correctly, ensure you are sending a URL link to the chart instead of embedding a large image file.

## Reference implementation
https://n8n.io/workflows/5204 (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/sentiment-analytics-visualizer/ via usecasesforagents.com