Team & Organizational · master area
Cross-Team Coordination
A growing team eventually has more than one chain running in parallel. The coordination problem is not staff allocation — it is shared state. Three artefacts handle it. Ad-hoc Slack channels do not.
Owners: Tech Lead, PO, Leadership Phase it lives in: Continuous The corpus principle this enacts: The artefacts are the coordination.
Where it lives in the chain
How to do this
Three artefacts handle the shared state between chains:
- Shared services registry — what does each chain consume from each other? Versioned, with owners. "Team Grading consumes auth service v2, owned by Team Platform. Deprecation: v1 sunset 2026-09-01."
- ADR cross-references — when one chain's ADR constrains another, both ADRs link. The downstream chain reads the upstream constraint as part of its own technical shaping.
- Portfolio review — sees all chains together. Catches the conflict that no individual cycle can see — "Team Grading's flag rollout collides with Team Billing's migration window."
What does NOT work
Ad-hoc Slack channels for coordination. They produce decisions no one can find next quarter. The decision was made; the artefact wasn't. Three months later, two chains are surprised by a constraint they both agreed to once, in a thread, on a Wednesday.
The same discipline applies between chains as within a chain: artefacts survive conversations. The Slack thread is where the decision is talked through; the artefact is where the decision lives. Without the artefact, the decision is rumour.
What good practice looks like
A new dependency surfaces — Team Grading needs Team Notifications to add an event. Process:
- Tech Leads meet for 30 minutes. Sketch the contract.
- Both teams write an ADR — Grading's "we depend on
ExamGradedevent from Notifications" and Notifications' "we exposeExamGradedto Grading; SLA: 99.9% delivery within 5s." - Both ADRs link to each other and to the registry.
- The registry's monthly read surfaces the new dependency to leadership.
When someone joins either team six months later, the why is in the artefact.