Class 5 · 5.5

Karpathy on vibe coding & rules for a commercial MVP

The person who named “vibe coding” has been narrating this shift all along. His three key posts — and the balanced mindset they point to — round out the class.

🎯 Goal: a balanced mental model⏱ Read: 8 min🧭 Type: perspective

01Three tweets, in order

Andrej Karpathy has narrated this whole shift in near-real-time. Read chronologically, his posts trace the arc from a playful idea to a serious craft.

Andrej Karpathy

@karpathy · Feb (last year)

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There’s a new kind of coding where you give in fully to the vibes, embrace the exponentials, and forget that the code even exists. It’s possible because the LLMs are getting too good.

The tweet that coined “vibe coding.” Playful, and about the fun of letting go.

Andrej Karpathy

@karpathy · December

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I’ve never felt this much behind as a programmer. I could be 10× more powerful if I could just string together what’s going on — agents, sub-agents, prompts, context, memory, modes, permissions, tools, plugins, skills, hooks, MCP, workflows, IDE integrations — and a need for an all-encompassing mental model.

The tweet that inspired this entire course. The whole point of these three weeks is to build exactly that mental model.

Andrej Karpathy

@karpathy · end of January

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A long, off-the-cuff reflection on how agentic coding is really shaping up — workflow, swarms, tenacity, speed-ups, leverage, fun, atrophy… and the coming “slop apocalypse.”

02The January reflection, unpacked

That last post is worth slowing down on. Each thread rings true in practice.

The workflow flip: from mostly typing with a little agent help, to mostly directing agents.

Watch it like a hawk

Swarm hype is early

The “no IDE, agent-swarm” movement is ahead of its time. Models still make mistakes; on code you care about, supervise closely — even while YOLOing.

Tenacity

They never tire

Agents work relentlessly — no fatigue, no demoralisation. They just keep going.

Speed-up = expansion

Hard to put a number on

Is it 2×? 10×? The honest answer: it feels less like raw velocity and more like doing far more than you would have.

Leverage & the loop

Bigger goals

Putting a capable model in a loop lets you aim at goals that were previously out of reach.

Fun

Builders vs coders

Agentic work splits engineers: those who love coding can feel loss; those who love building often enjoy it more.

Atrophy

Skills can fade

Lean on the AI too hard and your own coding sharpness dulls. A real risk to guard against.

The slop apocalypse

Karpathy braces for a year of LLM “slop” everywhere. The likely response — echoing the Jellyfin policy from 5.3 — is a backlash: a push toward concise, understood code without emoji-strewn README novels. Aim to be visibly not slop.

03The rules, one more time

The MVP mindset for building something real is the same discipline from 5.2, worth stating once more because it’s what separates a demo from a product.

Be the boss — in one breath

Invest in your agents.md (spec, style, success). Start simple and work incrementally, testing constantly. Don’t get lazy — challenge, demand evidence, and “watch it like a hawk.” Handle frustration by stepping back and trying differently.

04A healthy, balanced attitude

Don’t get swept up in the 10× hype, and don’t sour on the whole thing at the first wall. Expect mixed results, work incrementally and realistically, and the upside is genuinely enormous. Hold that balance and you’ll not only be productive — you’ll enjoy it.

Where this leaves you

That wraps Class 5 — your first real projects day. You broke the rules on purpose, then came back and owned the result. Next week we move to the command line, where these habits pay off even more.

✓ Key takeaways

Karpathy’s arc: “vibe coding” (fun) → “never felt so behind” (the mental model) → a sober January reflection.
His workflow flipped from 80% manual to 80% agents — but still “watch it like a hawk.”
The gain feels like expansion more than raw speed; beware skill atrophy and the coming slop.
The MVP mindset is the same discipline: be the boss, start simple, test, challenge, stay balanced.