If you use Claude mostly for chat or coding, the easy mistake is treating every new model like the same tool with a higher score. That is how you miss the real risk: you assume the same old prompt still works, then a stricter model exposes the part you never actually wrote down.
My read is simple: Opus 4.7's biggest upgrade is that it stops mind-reading bad prompts. This kind of launch is worth reading not just for how strong the model is, but for why the boundary got tighter.
Anthropic's own framing points that way. In "Introducing Claude Opus 4.7," they warn that instructions written for older Claude models may behave differently because 4.7 follows your words more literally [C001]. The migration guide sharpens the same point: less silent generalization, less guessing about unstated intent.
Plain English: if your old prompt said one thing and hoped Claude would figure out the rest, 4.7 is less likely to cover for you. That does not automatically mean it is worse. It means the fuzzy part may have been in the prompt, not magically solved by the model.
That is why this is more interesting as a boundary story than a pure capability story. The most discussable part is rarely that the model got stronger. It is why the strongest version stopped doing part of the work for you.
Boundary: this is a docs-only read, not a side-by-side test, user survey, or production run. The practical move is boring but useful: review vague prompts before you call 4.7 a free upgrade. Share this with the person who assumes newer always means safer.