> Finally, we've introduced thinking summaries for Claude 4 models that use a smaller model to condense lengthy thought processes. This summarization is only needed about 5% of the time—most thought processes are short enough to display in full. Users requiring raw chains of thought for advanced prompt engineering can contact sales about our new Developer Mode to retain full access.

Extremely cringe behaviour. Raw CoTs are super useful for debugging errors in data extraction pipelines.

After Deepseek R1 I had hope that other companies would be more open about these things.