AI coding tools are making developers 19% slower, not faster
Developers using AI are spending 19% longer on tasks than before. The tools aren’t broken. The workflows are.
At Business of Software USA, Ivan Barajas Vargas, CEO and co-founder of MuukTest, walked through findings from five of the most cited academic papers on AI in software development. His core argument: speed and efficiency are not the same thing. Code that needs endless review, security audits, and refactoring costs more time than it saves.
The Shadow AI Problem
There are now hundreds of AI coding tools available: Cursor, Copilot, Claude, GitHub’s own offerings, plus specialized tools for every framework. Most teams pick one by gut feel, try a second, and end up running both in production.
That’s shadow AI: unauthorized, unvetted tools loose in the development workflow. Each one opens its own security surface. A sales intern tries a new tool to help out. Credentials get copy-pasted into a system nobody’s vetted. Once that data leaks, it’s gone.
The fix Vargas recommends is blunt: pick one stack and enforce it. Write standards. Any team can write a prompt, but the effective ones write guidelines for how AI gets used in development, with input from business and product, not just engineering.
Hallucinations Are a Tax, Not a Bug
AI generates thousands of lines of code. Most of it is syntactically fine and conceptually plausible. Until you dig in and find APIs that don’t exist. That’s how these models work: they extrapolate from training data, and sometimes the extrapolation is fiction.
Vargas frames it simply: it’s like using a chainsaw. Powerful in trained hands. A mess in untrained ones. Auto-complete, refactoring, scaffolding, and root cause analysis all work, provided someone actually knows what they’re doing.
The structural fix is context. Load your RAG system or vector database with documentation, architecture decisions, and code standards. Test performance regularly. Don’t assume generated code scales just because it compiles. The more your team generates with AI, the more a senior developer ends up validating.
Senior Developers Are Now Full-Time Reviewers
Senior developers are reviewing five times more code than before AI entered the workflow. A junior developer with AI generates more code, faster. But every line needs review, testing, and validation.
The people you actually need for architecture, mentorship, and strategy are stuck validating what the junior team generated. More code doesn’t mean better code. AI writes like a junior developer: high output, some of it buggy, most of it carrying tech debt that compounds.
The burnout signal is worth watching. A tool that’s supposed to save time is quietly taxing your best people, and most teams haven’t noticed because the dashboard still says faster. The fix starts with acknowledging the shift: AI tools multiply senior workload, they don’t eliminate it.
That means monitoring load, and assigning ownership. If someone is responsible for vetting the AI, integrating it, and maintaining standards, the workflow stays manageable. If no one owns it, it spreads.
Where Vibe Coding Actually Belongs
The teams getting real value from AI aren’t treating it as a replacement for architecture or strategy. They’re treating it like a chainsaw: powerful, but only in trained hands with the guards on.
That means committing to one tool. Writing standards. Feeding the system context. Testing for performance. Instrumenting observability from day one so you know why things break. Naming owners. Watching developer load.
Vargas draws a clear line on scope: vibe coding belongs in prototypes, mockups, and small features. Not the core architecture of a fintech platform or a healthcare system. There, AI scaffolds and refactors. It doesn’t decide.
The vibes are only off if you skip the integration work and hope for the best.
Watch the full talk on the Business of Software website.
I’m founder of BizStack at Cagri Sarigoz LLC and a passionate advocate for entrepreneurs.
With over 14 years in tech, marketing, and AI, including my role as Head of SEO at CitizenShipper and co-founder of TaleBot at Intale AI, I’m dedicated to sharing genuine, useful product insights and tips.
At BizStack, I aim to cut through the digital noise to provide clear, actionable advice.
And more than all else, I’m a father to a (always) little girl and a husband.
Contact me at [email protected] for assistance.
