I rebuilt this blog with agentic workflows in a weekend

I gave myself a weekend and one rule: the agent writes the code, I write the harness. No hand-coding a component unless the loop genuinely couldn’t get there. By Sunday night the site was live - bilingual, with a per-language RSS feed. It was not a straight line.

The setup

The stack was settled before I started: Astro content collections, Markdown with frontmatter, one EN file and one NL file per post linked by a shared slug. The frontmatter contract came straight out of my /article skill, so the content model and the site model matched by construction:

title:        "I rebuilt this blog with agentic workflows in a weekend"
description:  "What the model nailed, what it broke, the numbers."
pubDate:      2026-06-28
lang:         en
tags:         [agentic, astro, i18n]
status:       deep-dive
translationOf: rebuilt-blog-weekend

Then I pointed the agent at it with a tight CLAUDE.md and let the loop run.

What the agent got right

The scaffolding was faster than I could have typed it. Locale-routed pages (/en/…, /nl/…), hreflang tags, per-language RSS - all correct on the first pass. It read the frontmatter contract once and never violated it. Syntax highlighting, the copy button on code blocks, the reading-time estimate: done while I made coffee.

Where it broke: i18n

Then the language switcher. The agent confidently wired /en/post to /nl/post - except the Dutch slug differs, and the switch 404’d on every translated post. It had assumed slug parity. It hadn’t. Two hours of me trusting green output that was green for the wrong reason.

The lesson wasn’t “the agent is bad at i18n.” It was: I let it invent the mapping instead of handing it one. The fix was four lines of my own.

The numbers

• ~11 h - total build, Saturday + Sunday
• 85% - committed lines agent-authored
• 2 h - lost to the i18n bug
• 1 - inaugural deep dive (this one)

Would I do it again

Yes - but with the harness tighter from the first commit. The agent is extraordinary at the tedious-but-known. It’s dangerous exactly where I’m lazy: the integration seams I’d rather not think about. The weekend didn’t save me from understanding my own site. It saved me from typing it.