Hallucination is also much better controlled in the context of agentic coding because outputs can be validated by running the code (or linters/LSP). I almost never notice hallucinations when I’m coding with AI, but when using AI for legal work (my real job) it hallucinates constantly and perniciously because the hallucinations are subtle—e.g., making up a crucial fact about a real case.

Yes, you can catch many mistakes that LLMs make whike coding, but I wouldn't necessarily call it "controlled." Every now and then the LLM will run into dead ends where it makes a certain mistake, the compiler or unit tests find the mistake, so it tries a different approach that also fails, and then it goes back to the first approach, then tries the second approach again, and gets stuck in an endless loop trying small variations on those two approaches over and over.

If you aren't paying attention it can spend a long time (and a lot of tokens) spinning in that loop. Sometimes there might be more than two approaches in the loop, which makes it even harder to see that it's repeating itself in a loop. It's pretty frustrating to see it working away productively (so you think) for 20 minutes or so only to finally notice what's going on

For coding the worst I've seen recently is gemini using or suggesting library methods that dont exist in c# which it catches when it builds the project (something I've told it to do to catch these.)

but for research it makes shit up all the time, I asked GPT5.5 to make me a build for Rogue Trader and not only did it use out of date info, it made up a bunch of skills that were NEVER in the game. I attribute that to there not being enough online information in the wikis or whatever but I wish it would just say "I dont know" instead of hallucinating but I know that's not how the tech works.