You are helping me build the following AI agent workflow.

## Goal
Daily Newsletter Summarization & Briefing: Automatically collects daily newsletters, summarizes them via AI, and sends a single structured briefing to your inbox.

## Specification
- What it does: Receive a concise daily briefing in your inbox that automatically gathers newsletters from Gmail, removes clutter, and summarizes the key points into one clear digest. You get a structured overview of your daily reading without manually scanning multiple emails or long articles.
- Trigger: On a schedule (Scheduled · daily)
- Autonomy: Fully hands-off
- Expected setup effort: about an afternoon
- Tools/services involved:
  - Gmail: Collecting newsletter emails
  - Google Sheets: Logging text chunks
  - LangChain Code: Processing and splitting text
  - Google Gemini Chat Model: Summarizing content into digest
  - Send Email: Delivering the daily briefing

## Known pitfalls, handle each one explicitly in your implementation
1. Large newsletters may exceed token limits so you must implement a robust chunking strategy that preserves context boundaries.
2. HTML parsing can fail on malformed emails so add error handling to fallback to raw text extraction if cleaning fails.
3. Email attachments are not processed by default so explicitly instruct users to forward only text-based newsletters or strip attachment references.

## Reference implementation
https://n8n.io/workflows/9633 (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/daily-newsletter-summarization-briefing/ via usecasesforagents.com