💡 New script: gmail-followup-tracker (unanswered email reminder system)

[github-actions[bot]]

Summary

A Google Apps Script that monitors sent emails tagged with a configurable label (e.g., "follow-up") and creates Google Tasks or sends reminder emails when no reply is received within a configurable timeframe. Supports per-label rules, customizable reminder intervals, and a Sheets-based tracking dashboard showing follow-up status across all monitored threads.

Market Signal

Email follow-up tracking is a premium feature in every major email productivity tool: Boomerang ($15/mo), Superhuman ($30/mo), HubSpot (enterprise pricing). No free, open-source Google Apps Script alternative exists. The email productivity market is rapidly growing with AI-powered tools like alfred_ ($24.99/mo) and Shortwave offering follow-up features as core differentiators. The open-source automation movement (n8n's $5.2B valuation, $100M+ ARR) demonstrates strong demand for free alternatives to paid productivity tools.

User Signal

"Forgetting to follow up on sent emails" is consistently rated a top-3 email productivity complaint in workplace surveys. The project's target users — individuals and small teams — are exactly the audience priced out of $15-30/mo tools. Gmail's snooze feature brings emails back to the inbox but does not check whether a reply was received, which is fundamentally different from follow-up tracking.

Technical Opportunity

Pure GAS implementation using Gmail search operators (in:sent, after:date, -has:userlabels) and thread ID matching. Google Tasks API is available as an Apps Script Advanced Service. The existing dual-layer architecture, config.gs pattern, and hourly trigger with shouldRunNow() schedule logic (proven in calendar-to-briefing-doc) apply directly. The deploy page can configure follow-up labels and reminder intervals via the same Step 4 config UI.

Assessment

Dimension	Score	Rationale
Feasibility	high	Pure GAS, no new APIs needed, extends proven patterns from existing scripts
Impact	high	Competes with $15-30/mo paid tools, addresses universal productivity pain point
Urgency	med	No immediate competitive pressure, but growing market for free alternatives

Adversarial Review

Strongest objection: Gmail's thread model makes reply detection imperfect. Replies to different threads, forwarded conversations, and BCC'd recipients could lead to false positives (reminding about emails that were actually answered).

Rebuttal: Gmail's thread ID is reliable for direct replies, covering the 90%+ case. Edge cases (reply to a different thread, side-channel response) are inherent to all follow-up tools, including paid ones. The MVP can use a simple heuristic: if the thread has a message from a non-sender participant after the tracked sent message, consider it replied. A configurable "skip if thread updated" option handles the common case cleanly.

Suggested Next Step

Create a tech spec defining the follow-up lifecycle: label application → tracking entry creation → periodic reply-check scan → reminder generation (Task or email) → tracking dashboard update. Define config.gs fields: follow-up label name, check interval, reminder method (Task/email), escalation rules.