Letting Codex Loose on My Codebases

From Edgar,

Welcome to A Vibe Coder, my newsletter where I upload my thoughts on current tech trends, experiements, and vibe coding best practices.

Shilling Myself

Codex First Impressions

Codex feels like someone finally remembered what we actually want from AI coding tools: less autocomplete, more progress. You point it at a repo, give it a task, and it spins up branches and makes concrete changes. It feels less like pair programming compapred to other AI dev tools and it’s closer to hiring a junior engineer who works fast and doesn’t mind grunt work.

How it Works

A typical workflow looks like this:

1. Connect your GitHub repo and issue a task.

2. Codex creates a new branch.

3. It writes code, commits changes, and opens a pull request.

4. You review, merge, or fix conflicts.

You’re not guiding every keystroke. You plan, prompt, and let Codex handle execution.

My Experience

On existing projects, Codex impressed me. I had some AWS CORS and terraform issues in FedRAG, the kind of thing that normally costs an afternoon. Codex jumped in and sorted them out without much back-and-forth.

On new projects, it was even more impressive. I spun up Base Lint, my baseline data CI/PR bot, and Codex scaffolded the whole thing at speed.

Not everything was smooth. One time, the “Ask” button (normally paired with the “Code” button) just wasn’t there. I decided to brute force it. I one-shot a testing suite on an older project. That went about as well as you’d expect. 39 minutes later, nothing. Codex is great at following through on scoped coding tasks, but it’s not built for big, messy one-and-done setups.

There are also some practical snags. Every new task creates a branch, which is elegant until you mess up Git. I did, badly. I had to resolve a merge conflict myself. Skill issue? Sure. But worth noting.

Final Verdict

I didn’t expect much going in. A coding bot in the browser didn’t exactly inspire confidence, and I’ve never loved ChatGPT’s coding models in other contexts. But Codex surprised me. It’s fast, it’s useful, and in the right lane it really does accelerate work.

It’s not the engineer you trust with your architecture, but it might be the one you hand annoying tasks to and thank later. If you approach it with the right expectations, it can feel less like a gimmick and more like a genuinely helpful teammate.

I give it 4 evaporated bodies of water out of 5 - 🌊 🌊 🌊 🌊

Thank Y’all

Used Codex yet? Tell us about your experience.

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Till next time,

Edgar | A Vibe Coder