Reject unknown telemetry fields at the sending boundary
Spreading an error object into an event accidentally includes headers and document metadata.
- Focused work estimate
- 2h + prerequisites
- Priority in the scenario
- High
- Engineering practice
- Runtime validation · Information boundaries
Estimated field mix
- Privacy engineering60%
- Security40%
Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence.
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Project context
A fictional document workspace wants to measure upload completion and failure. Its prototype sends filenames, document titles and raw errors to general analytics. Replace that path with a minimal event contract using synthetic traffic.
Setup prerequisites
- Create synthetic upload workflows and a local collector that captures received payloads.
- Define measurement questions and a separate restricted diagnostic store fixture.
Preceding work
Complete these dependencies, or supply their agreed outputs before taking this ticket.
Acceptance criteria
- Build payloads through a runtime schema with unknown-field rejection.
- Expose a typed interface that does not accept arbitrary payload spreading.
- Report rejection without echoing the rejected payload.
Implementation constraints
- The runtime boundary must handle loosely typed callers as well as normal TypeScript code.
Verification to include
- Send a valid completion and inspect the collector payload.
- Add token-like headers, nested objects and unknown properties; no event may reach the collector.
Deliverables
- Telemetry boundary and rejection tests
Rollout and recovery
Route events through the boundary before retiring the old sender.
Value of the work
For the engineer: Practice minimization, safe failure handling and correct aggregates.
For the team: Produce useful operational measurements with a reviewable collection boundary and disclosure regression suite.
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.