Trace Lineage: See every session behind a body of work
Last updated: October 27, 2026
Trace Lineage groups a person's related agent sessions that belong to the same piece of work. It is in limited rollout and is not on for every organization. Your Span account team can tell you whether it is on for yours.
Why it matters
Real work rarely happens in a single agent session. An engineer might build one feature across several sessions: exploring the codebase, planning, implementing, debugging, and writing tests before opening a PR. Grouping those sessions gives a fuller view of the cost and time behind a work item than the sessions that edited the merged code alone.
How it works
Span uses repository, branch, and PR evidence, along with inferred relationships between sessions, to group traces from the same person that belong to the same piece of work.
Setup
Trace Lineage is not something you can turn on yourself. Ask your Span account team whether it is on for your organization.
Things to know
Limited rollout. Trace Lineage is not on for every organization. To see how Span assigns session cost to pull requests, see AI Investment Overview.
It's a best-effort match. Lineage uses AI to infer which sessions are related, so a session may occasionally be grouped incorrectly or missed.
Grouping is automatic. Traces can't be linked or unlinked by hand.
Lineage connects sessions from the same person only.
Related articles
Understanding Agent Traces in Span (auspex)
Need help?
Contact your Span account team or reach out to support@span.app.