Qualities of a Professional Software Developer

In his post Vibe engineering, Simon Willison gave a list of attributes for seasoned professionals working with AI while producing quality software. These are essential qualities when you're looking to hiring a software contractor or consultant, or even a full-time dev.

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Strong Intuition

An instinct for what can be outsourced to AI and what you need to manually handle yourself. This is constantly evolving as the models and tools become more effective. A big part of working effectively with LLMs is maintaining a strong intuition for when they can best be applied.

Planning in advance.

Sitting down to hack something together goes much better if you start with a high level plan. Working with an agent makes this even more important—you can iterate on the plan first, then hand it off to the agent to write the code.

Having effective automation in place.

Continuous integration, automated formatting and linting, continuous deployment to a preview environment—all things that agentic coding tools can benefit from too. LLMs make writing quick automation scripts easier as well, which can help them then repeat tasks accurately and consistently next time.

Strong research skills.

There are dozens of ways to solve any given coding problem. Figuring out the best options and proving an approach has always been important, and remains a blocker on unleashing an agent to write the actual code.

The ability to ship to a preview environment.

If an agent builds a feature, having a way to safely preview that feature (without deploying it straight to production) makes reviews much more productive and greatly reduces the risk of shipping something broken.

Automated testing

If your project has a robust, comprehensive and stable test suite agentic coding tools can fly with it. Without tests? Your agent might claim something works without having actually tested it at all, plus any new change could break an unrelated feature without you realizing it. Test-first development is particularly effective with agents that can iterate in a loop.

If you’re going to really exploit the capabilities of these new tools, you need to be operating at the top of your game. You’re not just responsible for writing the code—you’re researching approaches, deciding on high-level architecture, writing specifications, defining success criteria, designing agentic loops, planning QA, managing a growing army of weird digital interns who will absolutely cheat if you give them a chance, and spending so much time on code review.

From: Vibe Engineering by Simon Willison