I Let an AI Re-Platform My CI Pipeline. Here's What Broke.

Originally published at wostal.eu . TL;DR : I handed a CI re-platform — GitHub Actions → Argo Workflows, GitHub → Codeberg — to an AI agent. The rewrite looked correct and passed lint, but it didn't account for one thing: the runtime environment had changed completely. The old runner was an external VM; the new one is a pod inside the cluster, where Tailscale IPs aren't routable. Nobody ran the pipeline end-to-end, so every difference stayed as a landmine — six of them. The worst part wasn't the AI's mistake. It was that I spent hours blaming the network when the real culprit was a single missing newline in an SSH key. This is the companion to a different incident. While I was migrating my homelab k3s control plane from SQLite to etcd , the pipeline that ran that migration turned out to be broken in ways that taught me more than the migration itself. In this post I'll cover: Where the mess came from — an AI-assisted CI re-platform that nobody validated end-to-end The phantom CNI bug — hours of chasing MTU, Tailscale, firewall, and conntrack The real culprit — a single missing newline in an SSH key Why early failures hide later ones — six latent bugs, surfaced one at a time The lesson about delegating migrations — to a human or an AI Where the mess came from The entire CI had just been migrated from GitHub Actions to Argo Workflows , and from GitHub to Codeberg — and that migration was handed to an AI agent 🙂. The re-platforming rewrote the logic roughly 1:1, but it didn't catch that the runtime environment had changed fundamentally . The old runner (GitHub Actions / ARC) behaved one way; the new one is a pod in the cluster — from which Tailscale IPs aren't routable, but private IPs are. Nobody (human or AI) ran the pipeline end-to-end, so all of those differences stayed as landmines. That's why there were six latent bugs and the hang I'm about to describe — not random faults, but traces of a GHA→Argo translation that was never validated in the new environment. The p