Define version selection and unsupported-version errors
Clients cannot tell which contract a request will receive.
- Focused work estimate
- 2h + prerequisites
- Priority in the scenario
- High
- Engineering practice
- REST design
Estimated field mix
- API design100%
Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence.
Review it, then add it to your workspace.
The board opens an editable draft; nothing is saved until you confirm it. Sign-in and workspace permissions apply, and Demo boards remain ephemeral.
Project context
A fictional inventory platform must replace a legacy availability response. Existing partners upgrade on different schedules, and the team needs a versioned transition.
Setup prerequisites
- Create two local API versions and synthetic partner clients with different upgrade schedules; no real partner traffic.
Preceding work
Complete these dependencies, or supply their agreed outputs before taking this ticket.
Acceptance criteria
- Choose one explicit version selection rule.
- Document a deterministic default only if retained intentionally.
- Return structured errors for unsupported versions.
Implementation constraints
- Keep routes under /api/v1 and /api/v2 in the scenario.
Verification to include
- Request each supported version.
- Request an unknown version and inspect its documented problem response.
Deliverables
- Version selection contract.
Rollout and recovery
Introduce explicit selection before changing existing defaults.
Value of the work
For the engineer: Practice public-contract design, compatible evolution, and client lifecycle management.
For the team: Provide a predictable migration that keeps supported integrations inspectable and recoverable.
Evidence boundaries
Outcome Evidence: Tests, patches, and runbooks are requested deliverables. They become Outcome Evidence only through a qualified Mission and immutable Evidence IDs.
Ownership Evidence: Independent adaptation must be observed under a declared verification policy and cite immutable Evidence IDs. Completing a planning ticket establishes no Ownership Evidence.