💡 New script: sheets-data-watchdog (smart spreadsheet monitoring with configurable threshold alerts)

[github-actions[bot]]

Summary

Automated Google Sheets monitoring that watches cell values against configurable thresholds and sends email alerts when conditions are met. Supports numeric bounds, text pattern matching, blank-cell detection, and formula-error monitoring. Configurable via config.gs with alert recipients, check intervals, and rule definitions. This would be the project's first Sheets-native script, opening a new product category.

Market Signal

5+ paid Google Workspace Marketplace add-ons dominate this space — Alerts & Notifications alone has 3M+ installs, alongside Magic Cell Notifications and RealTime Sheets Monitor. Zapier charges $19.99/mo+ for equivalent Google Sheets monitoring triggers. Zero free, open-source alternatives exist. The paid add-on market validates massive demand while leaving a clear gap for a FOSS solution that aligns with this project's mission.

User Signal

Google Sheets is the most-used Workspace app after Gmail. Data monitoring is consistently the top automation use case in Sheets community forums. The project currently has zero Sheets-native scripts — every existing script focuses on Gmail, Calendar, or Drive. Sheets monitoring addresses a completely unserved product surface while leveraging the same zero-code deployment model.

Technical Opportunity

Follows the project's established architecture exactly:

• onEdit trigger for real-time change detection
• Scheduled time-based trigger for periodic full-scan checks (defense-in-depth for changes that onEdit misses, e.g., script/API writes)
• Config-driven rule definitions in config.gs using the existing pattern
• MailApp for alert delivery
• The deploy page's Step 4 config UI can render rule configuration via the existing SCRIPT_CATALOG schema pattern

Architecture: code.gs (thin wrapper) → src/index.js (testable rule evaluation + alert logic) → config.gs (rule definitions, recipients, thresholds).

Assessment

Dimension	Score	Rationale
Feasibility	high	Uses standard GAS APIs (onEdit, SpreadsheetApp, MailApp, ScriptApp.newTrigger). Follows established project patterns exactly.
Impact	high	Opens new product category (Sheets). Addresses 3M+-install proven demand. Free alternative to paid tools.
Urgency	med	Paid alternatives exist and serve the market. No time-sensitive API window, but first-mover in FOSS GAS space.

Adversarial Review

Strongest objection: onEdit triggers don't fire for programmatic changes (script edits, data imports, API writes), creating silent monitoring gaps that could give users false confidence.

Rebuttal: Supplement onEdit with scheduled full-scan checks (e.g., every 15 minutes) that compare current cell values against stored snapshots. The dual-trigger approach (real-time + periodic) provides defense-in-depth monitoring — the exact same pattern used by the most popular paid add-on (Alerts & Notifications). Document the limitation clearly so users understand the monitoring model.

Suggested Next Step

Write a minimal PRD covering: rule definition schema (numeric threshold, text pattern match, blank-cell detection, formula-error types), alert delivery model (immediate email vs. batched digest), and config.gs structure. Then implement a 2-rule MVP (numeric threshold + blank detection) with full test coverage following TDD.