Keep a long conversation responsive without hiding context
An 800-message synthetic conversation makes expanding attachments slow. Reduce initial rendering while preserving chronological reading and position when older messages load.
- Focused work estimate
- 2h 30m + prerequisites
- Priority in the scenario
- Medium
- Engineering practice
- Performance profiling · Pagination · Accessibility
Estimated field mix
- Performance engineering50%
- Frontend30%
- Accessibility20%
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
The fictional Alder support team handles billing and delivery conversations in a browser console. Agents keep several tickets open, share filtered queues, and work through unreliable office Wi-Fi. The API contract returns ticket revisions and cursor-based pages; work stays within the console and its test adapter.
Setup prerequisites
- A ticket-list and reply API contract to implement or stub
- Synthetic conversations across two organizations with revision conflicts
Preceding work
Complete these dependencies, or supply their agreed outputs before taking this ticket.
Acceptance criteria
- Initial rendering uses a bounded window and explicit load-older control.
- Prepending older messages preserves the visible anchor and keyboard focus.
- A before/after profile on the same fixture records the performance budget and measurement environment.
Implementation constraints
- Prefer explicit pagination if virtualization would break assistive-technology reading order.
Verification to include
- Profile the 800-message fixture and load two older pages without a scroll jump.
- Fail and retry an older-page request; no messages duplicate and the current position remains.
Deliverables
- Bounded message rendering and reproducible profile note
Rollout and recovery
Enable above an agreed conversation size; restore full rendering if reading order regresses.
Value of the work
For the engineer: Practice state ownership, asynchronous races, accessible interaction, and recovery in bounded changes.
For the team: Inspect how an engineer protects agent work and handles failures that interrupt support operations.
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.