pub async fn json(
harness: &AgentHarness,
_args: &Args,
initial: Option<String>,
extra_messages: &[String],
) -> i32Expand description
json mode: emit each harness event as a JSON line on stdout, run the
prompts, then emit a terminal result line carrying the outcome + final
text. Mirrors TS runPrintMode (mode === "json") streaming every event.