This is my workflow which I find very productive with Agentic AI.
Disclaimer: I'm doing a CAD-like engineering desktop app, and I'm using VS 2026 Copilot, so YMMV.
When I get a Jira ticket, I will first diagnose the problem, and then ask AI to write a test case for it that will reproduce the problem, with guidance on what/how to do the test case (you will be surprised to know how many geometry, seemingly visual problems can be unit tested), and if necessary I provide clues (like which files to read, etc.) for AI to look at, and ask AI to just go and fix the test.
Often AI can do that; AI can make the test pass and make sure that adjacent tests also pass. If in doubt, I will check the output reasoning. I then verify that the fix is done properly via visual inspection (remember, this is a desktop app), and I ask for clarification if needed.
Then at night I'll let my automated test suites run... and oops! Regression found! Who broke it? AI or human? Who cares. I just tell AI that between these times one of the commits must have broken the code — can you please fix it for me? And AI can do that.
This works for small or medium feature implementation, trival bugfixes, or even annoying geometrical problems that require me to dig out the needle in the haystack. So the productivity gain is very real. But I haven't tried it on feature that requires weeks or months for implementation, maybe I should try it next time.
It's hard to describe the feeling. It's just that the AI is working like a very capable (junior?) programmer; both might not have full domain knowledge, but with strong test suites and senior guidance, both can go very far. And of course AI is cheaper and a lot more effective.