Until now we've been using Sonnet 4 to power an editing agent in ApostropheCMS. Sonnet is a good price/quality/speed compromise, but sometimes when giving it a large set of instructions it would miss half of them. At least until we told it to go back and try again.

In my early tests tonight, Sonnet 5 is a LOT better out of the box. It's one-shotting complex instructions. It also recovered independently from bad instructions that led to an uninformative 400 error by using its schema-fetching tool to figure out there were was too much input.

If I have to gripe about something: it interpreted another impossible instruction by quietly discarding the input in question. But, the way it did it is... kinda exactly what anybody else would do, if they weren't in a position to change the implementation.

This is, obviously, early days but I'm impressed.