What
When Claude Code sends a question to an interface host (the program displaying Claude Code), it now gets back the answer together with a reason. The reason is either that the question was never asked or the cause of the error. Before, any failure simply returned nothing. A separate check on arguments passed between steps also gained a path for arguments that were never applied.
Why
This is internal groundwork for interface hosts and does not change anything a reader does directly.
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubt
What uses these failure reasons is not shown.