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View from the cockpit onto a coastal road: a robot hand and a human hand from the passenger seat grip the steering wheel together, with the words “AI Autonomy?” above

How autonomous was my AI engineering agent, really?

100% of artifacts by the AI agent, 79% of decisions made autonomously, 8 interventions by me. How autonomous my engineering agent was and how to improve it.

Automatically translated from German · Read the original

Julian Weyer
Julian Weyer October 14, 2026 · 4 min read
AI ·AI ·Agentic AI ·4 min read

On a whim, I set out to develop an autonomous engineering agent and gave it one task: Design me a DIY robot, from the requirements document through CAD and simulation to the firmware. Now, several chat sessions later, I have a finished design, a shopping list, and a firm determination to build the thing (here it is in the simulation). But how autonomous was my agent, really?

I could of course start spinning tall tales here. That AI has arrived and engineers are no longer needed. And yes: they need to brace themselves (we do). At the very least, they should urgently get to grips with agentic frameworks and the APIs of their CAD and PLM environments. Because those are the gateway to much of what will change engineering in the future.

But no: my agent did not work fully autonomously. I tried to put that into numbers:

How autonomous was the agent? The agent created 100 percent of the 353 artifacts autonomously, excluding rules, marketing and supplied parts. It made 15 of 19 decisions autonomously, or 79 percent. There were 8 significant human interventions: 3 direction decisions and 5 major agent blunders. HOW AUTONOMOUS WAS THE AGENT? 100% of artifacts created autonomously 353 files: code, CAD, SysML, simulations, requirements, tests, docs 79% 15 of 19 decisions made autonomously 17 ADRs and 2 handoff decisions; the 4 pale boxes were decided by the human 8 Significant human interventions 3 direction decisions (white), 5 major agent blunders (hatched)

I feel like I’m repeating myself when I say: Without AI, this project would not have existed — but without me, it wouldn’t have either. But that sums it up pretty well. Over the course of the experiment, I saw how much potential AI already has, but also where its limits still lie. And for now, I’d like to raise two perspectives:

Two perspectives: model and harness

The limit of the model. AI has nearly unlimited world knowledge. But it sometimes struggles to draw the right conclusions at the right moment. This is a systemic limit that can only be overcome to a certain extent by future model generations,… but:

The compensation through the harness. The capabilities of the frameworks (“harnesses”) around AI models can make up for some of the blind spots of today’s models.

That’s why, with my experiment, I’m still far from reaching the limit of what’s possible, even with current models. I believe many of the weaknesses I saw can be compensated for with improvements to my operating model. For now, the robot will first be physically built in its current design draft, but right after that I plan to tackle the next iteration of my operating model.

I also want to take the whole project to the next level. So far, the foundation of my agent is the coding agent Claude Code. It’s already pretty good, but it actually comes from a different background. And as luck would have it, PROSTEP has its own agentic framework tailored precisely to PLM applications. It would be a shame not to use it for the next round ;-)

The worst blunders

So it’s not just numbers: these were my agent’s biggest blunders, and what would probably have prevented them.

BlunderWhat might have caught it
Rectangular aluminum frame instead of a round acrylic chassis, even though the kit is actually unambiguousDesign guideline: check assumptions from research against the datasheet and image
Missing fastening for the front panelsCompleteness check of all parts and connections
Incomplete assembly modelCompleteness check of all parts and connections
Parts in the simulation not correctly alignedAutomated check of the raw data (position, bounding box) instead of looking at the screenshot
Nonsensical simplifications in the simulationDesign guideline: justify model assumptions and verify them against a hand calculation