Adds `--experimentalToonFormat` boolean flag, controlling how structured
content is formatted in text response.
By default, custom shorthand format is used. With this flag, TOON format
(see https://github.com/toon-format/toon) is used instead.
TOON format is supposed to be more token-efficient and less error-prone
for agents to understand than json, but it's not clear if it will be
better on those metrics than the custom format used so far. (Evals
pending)
One clear benefit over custom format would be less code to maintain if
we decide to fully switch to TOON, due to dropping custom formatters and
reusing json formatters used for structuredContent anyways.
Co-authored-by: Piotr Paulski <piotrpaulski@chromium.org>
Piotr Paulski
aa33bff19f