When GitHub Copilot launched, reactions in the Eggstech team were sharply divided: half excited, half worried. Eighteen months later, we have enough data to speak plainly about what actually changed.
What AI genuinely does well
Boilerplate and scaffolding: CRUD APIs, migration scripts, test fixtures, Dockerfiles — anything with a clear, repeatable pattern. Our developers save 30–40% of their time on these tasks.
First-pass code review: Before pushing a PR, running AI over the diff to catch obvious issues (null checks, SQL injection patterns, performance anti-patterns) meaningfully reduces review comments. Senior developer reviews become more focused on architecture and business logic.
Documentation and test generation: Writing docstrings, generating unit tests from function signatures — the tasks developers most readily skip and most consistently regret skipping.
What AI still can’t do (after 18 months)
Domain-specific decisions: AI doesn’t know your client’s business rules, or why a field called “status” has 7 values instead of 3. Project-specific context must come from people.
Debug production issues: Production bugs typically involve interactions between multiple systems, timing issues, or data corruption — areas where AI lacks the context to debug effectively. It can suggest; it cannot lead.
Architecture decisions: “Microservices or monolith?” is a question about business constraints, team size, and operational maturity — not about code patterns.
Why senior developers benefit more than juniors
This seems counterintuitive but follows a clear logic: AI output requires someone who can evaluate its quality. A senior developer recognises when AI suggests something that sounds correct but will break at scale. Junior developers tend to accept output without the critical thinking to identify when it’s wrong.
Our practical conclusion: AI doesn’t replace developers — it replaces a portion of the tedious work developers do. The developers who use AI most effectively aren’t those who trust it most, but those who know how to ask the right questions and when to override it.
