What
When a tool returns output, Claude Code checks whether that output contains images. That check now also returns true for document blocks. A tool is an action Claude can take, such as reading a file.
Why
Documents, such as PDFs, in a tool's output should now be treated the same way as images.
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubt
It is not clear which parts of Claude Code rely on this check, so the practical effect is unknown.