I was trying to use Opus 4.6 in Claude Code to add some functionality to python code intended to run on a cluster and it didn't have any python environment in its remote environment. It needed to look at the schema of a parquet file to make sure it did things right and couldn't figure out how to do so with code because for god knows what reason there is no python environment in the dev environment for code intended to be run on a compute cluster in Python. Eventually it decided to just examine the raw binary bytes of the header, and then wrote perfectly functional code based on that.

On a different note I recently uploaded several thousand scraped IPO prospectuses to the gpt 5.4 mini API to parse and extract certain data. I ordered it in the system prompt to respond exactly with a specified JSON schema. When I got the results back and processed them there was not a single JSON parse error whatsoever. The model didn't have a single hallucination that created malformed JSON or JSON not matching the given schema across several hundred million input tokens and several million output tokens. And this was 5.4 Mini!