What probably matters to youSection of the release
What
The streaming message schema adds an optional context_usage field carrying a machine-readable twin of the /context breakdown, so tools consuming the stream no longer have to parse the markdown table.
Details
It sits at the wrapper level, as a sibling of message.content on the synthetic assistant message that delivers the table.
Deliberately not replayed back to the model.
The markdown table remains canonical for clients that do not receive the field.
Evidence
Structured twin of the /context report, carried on the synthetic assistant message that delivers the markdown table.
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
