Module demux 

The pure stdout demux — plain CLI stdout lines → neutral aion_core::ActivityEvents. The stdout demux — the pure translation from a plain CLI agent’s interleaved stdout lines into neutral [ActivityEvent]s.

This is the case-(b) analogue of the Norn adapter’s translate module, and the whole point of the observability-only shape: a plain-stdout agent has no structured channel, so its transcript is recovered by parsing the interleaved lines it prints. The demux is deliberately lossless: any line the classifier does not recognise falls through to [ActivityEventKind::Raw] carrying the verbatim line, so nothing an agent prints is ever silently dropped.

The recognised shape

A line that parses as a JSON object with a "type" string is mapped onto a neutral kind:

line type	neutral kind
"message" (with "text")	[ActivityEventKind::Message] (assistant role)
"tool_call"	[ActivityEventKind::ToolCall]
"tool_result"	[ActivityEventKind::ToolResult]
"stop" (with "reason")	[ActivityEventKind::Stop]

Everything else — a non-JSON log line, a JSON value without a known type, an empty line — is a [ActivityEventKind::Raw]. This mirrors real observability-only CLIs, which interleave a little structured output with free-form logging.

The demux is pure and independently tested; the session (crate::session) is the only place that reads the child’s stdout and stamps ordering onto the events this produces.

Structs

EventIdentity

The (workflow, run, activity, attempt) identity stamped onto every demuxed event.

Functions

line_to_event

Maps one line of the child’s stdout into a neutral ActivityEvent.