Streaming

The runtime exposes every execution as a stream of events, independent of any wire format:

event	when
execution.started	always first
tool.started	the tool is about to run (after policies, validation and idempotency)
tool.completed	the tool finished, with duration_ms and ok
execution.completed	always last, with the full result and replayed

Replays and early rejections skip the tool.* events.

Over HTTP (SSE)

Send the normal execute request with Accept: text/event-stream:

$ curl -N localhost:3000/agent/execute -H 'content-type: application/json' \
    -H 'accept: text/event-stream' -d '{"tool":"search","arguments":{"query":"mouse"}}'
event: execution.started
data: {"execution_id":"exec_…","tool":"search"}

event: tool.started
data: {"execution_id":"exec_…","tool":"search"}

event: tool.completed
data: {"duration_ms":0,"execution_id":"exec_…","ok":true,"tool":"search"}

event: execution.completed
data: {"_agent":{"cacheable":true,"next_actions":[]},"data":{…},"execution_id":"exec_…","replayed":false,"status":"completed"}

The execution.completed payload is the same body a JSON response would have, plus replayed.

In-process

use futures_util::StreamExt;

let runtime = carmy::app().build()?;
let request = carmy::runtime::execution_request("search", serde_json::json!({ "query": "x" }));
let mut events = runtime.execute_stream(request);
while let Some(event) = events.next().await {
    println!("{}", event.name());
}

The stream drives the execution itself; nothing is spawned in the background. Dropping the stream (for example, when an SSE client disconnects) cancels the execution, exactly like dropping a normal request.