Confident Is Not Correct: Three Signs That Claude Is Guessing

The answer arrives clean, well-formatted, and certain. You run it. The config flag doesn't exist. Nothing in the response told you the difference between the parts it was sure about and the parts it filled in. The syntax was right. The explanation was reasonable. The flag had a sensible name and a clear purpose. It just wasn't real. This is a calibration problem, not a trust problem. "Don't trust AI" is useless advice. It tells you to doubt everything, which is the same as doubting nothing, because you can't actually work that way. What you need instead is a way to tell which parts of an answer are grounded and which were filled in. There are patterns to look for, and once you know them, they are hard to miss. 🔍 Why this affects beginners specifically This isn't about intelligence. It's about experience. An engineer with a few years behind them has already lost time to a function that didn't exist. They have wasted an afternoon on a config parameter that turned out to belong to a different engine. They have built up a collection of "that looked right but wasn't" memories, and those memories now activate automatically. A small feeling that says check this one before they run it. Beginners haven't had those afternoons yet. The pattern recognition that comes from repeated failures doesn't exist, because the failures haven't happened. Everything arrives in the same confident tone, and without past mistakes to compare against, there is no internal signal separating a grounded answer from a made-up one. That's not a character flaw. It's missing experience, and it can be partly replaced with three concrete things to look for. ✅ The three signs These aren't perfect. They are a minimum standard, and they catch the common cases. I'll be clear about what they miss at the end. Sign 1: Very specific details with no source When the answer includes a precise detail (a specific config flag, a particular function signature, an exact version number) and doesn't say where that detail