Instrumentation and event-schema design upstream

Instrumentation and event-schema design upstream

You don't only analyze what's logged - you shape what gets logged. If the event schema doesn't carry model version, deploy id and a stable run id, no downstream cleverness recovers them. Designing instrumentation is the most impactful tooling work, because a missing field is a regression you can never attribute.

• Insist on a stable run_id and event ordering so sessionization is possible at all.
• Carry the triage dimensions (model version, deploy/commit, region, client version, surface) on the events themselves.
• Log the censoring signal - start, heartbeat, terminal - so aborted runs are distinguishable from fast ones.
• Treat schema as an interface: changes are versioned and announced, not silent.