ToolOutput

One part of what came back from a call, in the order it came back.

An answer is not always writing. A tool that looks at a screen answers with a picture, and a tool that writes a file answers with the file. Both are artifacts — things the call produced rather than said — and neither crosses this wire as bytes.

A picture is named by where it sits: the call it came back from, and which part of that answer it is. So a page asks the host that served the transcript for it, and that host reads it out of the session it was already reading. A file is named and nothing more: its bytes are on the machine that ran the session, and offering to fetch them would turn a transcript into a way into that machine.

The parts keep the order they arrived in, because the words a tool wrote around a picture are about it.