There's a class of bug that the current generation of AI coding assistants reliably produces, and it's worth naming because the fix is real and available now. The bug: your assistant calls a library method that doesn't exist . Not a typo. Not a logic error. A confident, well-formatted, syntactically perfect call to a method that has been deprecated, renamed, or never existed in the version you're using. The compiler tells you. You go back, ask the assistant to fix it, and 40% of the time it suggests a different method that also doesn't exist. By the time you've corrected it manually, you've burned 15 minutes and 30,000 tokens. This isn't because the model is bad. It's because the model's training data is a snapshot , and library code is a stream . The data set knew StackExchange.Redis 2.5; you're on 2.8. The data set knew Tokio when its runtime API had a different shape. The model is doing exactly what it was trained to do — reproduce patterns it saw — and the patterns have moved.…