Signals

The same two wrappers produce all three OpenTelemetry signals. Each one is on by default and costs a function call if your app hasn’t configured that signal, so you get whatever you already run.

Traces

One span per program, one per call it made, nested. The shape of a single run.

Covered in Output.

Metrics

Two histograms, both in seconds, for questions across many runs.

The second one is conditional, and this is the interesting part. Those dimensions are only added when you attested crossing.target. If you didn’t, the tool name is whatever the program said it called, and a metric has nowhere to record that doubt, so it would turn a claim into a fact that nothing downstream could question. So the dimensions get dropped and you get an undimensioned duration distribution instead. Less useful, not a lie.

Calls that ended abandoned are not recorded at all. Their duration is zero by construction, so counting them would put a fiction in the distribution.

You don’t need a collector for these. They come straight from your app through whatever metrics exporter you already have. The collector is still worth running if something else in your pipeline derives metrics from span names, because that you can’t control from here.

Logs

One record when a run starts, one when it ends.

{
  "event.name": "code_mode.execution.started",
  "body": "a program dispatch started",
  "trace_id": "7269fe4c…",
  "span_id": "a1fa92d3…",
  "code_mode.execution.id": "run-1"
}

The starting record is the point. A span only exports when it ends, so a run that’s still going, or one that hung, isn’t in your trace at all. It looks exactly like a run that never happened. The log record is the only thing in the whole model that says a run is in flight right now.

Both records carry the trace and span id, so they’re a view of the trace rather than a second source of truth. Join on those ids and you’re back in the waterfall.

This needs @opentelemetry/api-logs, which is an optional peer dependency. If it isn’t installed, log records are silently skipped and everything else works.

Switching off

codeMode({
  capabilities,
  signals: { metrics: false, logs: false },
});

Traces always emit. The other two are on unless you say otherwise.

No OpenTelemetry

If you run none of this, use your logger instead. You lose metrics and the waterfall, and keep the vocabulary.