# Vibe Coding vs Agentic Engineering

**June 4, 2026**

Vibe coding is prompting and shipping whatever comes out. Agentic engineering is building systems that produce reliable, verifiable results. They are not the same thing.

## The 5 Hard Rules

**1. Risk compounds with runtime.** A 1% per-turn failure rate equals a 63% chance of disaster over 100 turns. Long-running agents are not safer. They are more exposed.

**2. If your agent can write AND execute code, you are back at L1 security.** The marquee break: agent writes cleanup.py, runs python cleanup.py, your production data is gone. The security hook never fired because it only saw "python cleanup.py."

**3. Every turn is a roll of the dice.** Modern models refuse well 99% of the time. That last 1% grows with every feature release. Engineer the harness for the 1%, not the 99%.

**4. Token costs scale with loop depth, not task complexity.** A simple task with a bad loop costs 10x more than a complex task with a clean loop. Optimize the loop first.

**5. What you cannot measure, you cannot improve.** Every agent system needs: cost per task, success rate, loop efficiency, failure mode tracking.

## The Practical Difference

| Dimension | Vibe Coding | Agentic Engineering |
|-----------|-------------|-------------------|
| Approach | Prompt and pray | Build and verify |
| Security | Trust the model | Trust the harness |
| Cost | Unknown until the bill arrives | Tracked and optimized |
| Quality | Whatever comes out | Measured against golden dataset |
| Iteration | Try another prompt | Fix the harness |

## The Karpathy Framing

At Sequoia Ascent 2026, Andrej Karpathy said: "Vibe coding raises the floor. Agentic engineering raises the ceiling." Vibe coding makes mediocre engineers productive. Agentic engineering makes great engineers extraordinary.

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*From Module 1 of the [Agentic Engineering Course](/). The first module establishes the foundations that the rest of the course builds on.*
