Agentic session (subagent-driven development + systematic-debugging) fixed a bug but didn't catch that its own alerting had been silently broken for 5 days

Context: working session on a personal production service (career-activity-pipeline), using Claude Code with the superpowers plugin (systematic-debugging, brainstorming, writing-plans, subagent-driven-development skills) and multiple dispatched subagents for implementation + code review.

What happened: a real production bug (SQLite jobs contending for a single writer lock, causing recurring "database is locked" errors) was diagnosed and fixed correctly, with a full subagent-driven pipeline: brainstorming → spec → plan → 5 implementer/reviewer subagent pairs → a final opus-tier whole-branch review → deploy.

The gap: this bug's actual production impact was much worse than what got fixed — for 5 straight days prior, the core pipeline (capture: 80% failure rate, distiller: 100% failure rate, synthesis: produced zero output the entire time) was down, and the three-layer alerting system built specifically to surface exactly this kind of failure never fired, because the failures were escaping before reaching the alerting code path. None of this was caught by the extensive agentic process — it was only surfaced because the user manually noticed no Telegram/ntfy notifications and no new Notion drafts for days, and pushed back asking why.

Feedback: a heavyweight, multi-agent, multi-review development process caught and fixed a bug once pointed at it, but had no mechanism to notice that the thing meant to catch failures was itself failing silently in production the whole time. For a paying subscriber relying on this for a real production service, that's a significant gap between the amount of process/tooling used and the actual outcome delivered.