Cut over a 45-million-message alerting system with Claude Code and an operator go

Open Graph image from Kaizen’s Claude Code alerting-system cutover article

Kaizen (Ashish Tonse, Oct 6, 2026) moved a nine-year-old alerting system that had sent/received 45 million messages onto their main platform with Claude Code running a 61-step runbook. An operator approved every production write (28 GO steps). Result they report: ~17,000 residents and 133,000 subscriptions moved between 9:45 and 12:50, both new apps released by 12:15, reminders paused 47 minutes on a quiet Friday morning, and the next evening runs went out clean.

Try it yourself

What you get

A rehearsed, operator-gated production cutover that an agent can drive step by step.

Tools

  • Claude Code
  • Written runbook
  • Step dashboard
  • Production + copy environments

Time / cost: Article: cutover window 9:45–12:50; published Oct 6, 2026

Steps

  1. Put every step on one page: command, expected output, failure action, GO or not.
  2. Dry-run until mismatches become runbook fixes, not surprises.
  3. On the day: Claude runs reads alone; waits for the operator on writes.
  4. Log each result to a shared dashboard before the next step.

Copy-ready prompt

You are running our cutover from this runbook page. For each step:
1. Restate the command and expected output.
2. If the step is GO, wait for my explicit “go”.
3. Run it, compare output, write pass/fail + raw output to the dashboard.
4. On mismatch: stop, propose a fix, wait.
Start at step 1. Never skip a GO.

Prompt written by AgentPlays, based on Kaizen’s Claude Code cutover. Check the output yourself and approve before anything is sent or bought.

Watch out: Production messaging. Keep a human on irreversible steps and a pasteable manual fallback if the model drops.

Proof / source

Second-hand report Kaizen public post: 61 steps, 17k residents, 133k subscriptions, 47-minute pause, apps out by 12:15.

In their words

We just moved an alerting system that has sent and received 45 million messages onto our main platform. … We ran it with Claude Code, from a runbook we had written and rehearsed with it. … The run started at 9:45 and finished at 12:50, well inside the window. About 17,000 residents and 133,000 subscriptions moved over, and both apps were released by 12:15. Reminders were paused for 47 minutes, on a Friday morning when none were due.

— Ashish Tonse on Kaizen

Read the original source ↗

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