US-402: Span Coverage Audit

1. Story Title

Audit and improve distributed trace span coverage for critical flows

2. Context / Background

Tracing enables performance diagnostics; current coverage unverified and may miss key user journeys.

3. User Persona

Primary: Platform Engineer Secondary: SRE / Observability Analyst

4. Problem Statement

Insufficient span coverage obscures root cause analysis and latency hotspots.

5. Desired Outcome

Generate coverage report, identify missing critical spans (signup, leave request, document upload), implement instrumentation improvements and sampling adjustments.

6. Business Value

Faster incident triage; reliable performance baselines for optimization decisions.

7. Scope (In / Out)

In: coverage script/report, instrumentation additions, sampling config update, high-cardinality attribute audit. Out: Automatic trace summarization AI, anomaly detection integration.

8. Acceptance Criteria (BDD)

Scenario: Coverage report generated
  Given instrumentation baseline
  When audit script runs
  Then a report lists spans per critical flow & missing spans

Scenario: Missing span flagged
  Given signup lacks span for claim mapping
  When audit runs
  Then report marks gap
  And story tasks created

Scenario: High cardinality attribute prevented
  Given proposed attribute userEmail
  When validation runs
  Then warning blocks addition

Scenario: Sampling config updated
  Given new target 80% for activation flow
  When config deployed
  Then traces show increased retention

9. UX Notes / References

Report as Markdown + metrics dashboard annotation; config changes tracked in version control.

10. Data / Domain Model Impact

No DB changes; config & report artefacts.

11. NFR Touchpoints

• Performance: instrumentation overhead minimal (<2% CPU).
• Observability: improved trace completeness.
• Security: avoid PII in span attributes.

12. Dependencies

Existing logging/tracing guidelines; observability stack; isolation guard for context IDs.

13. Risks & Mitigations

Risk	Impact	Probability	Mitigation
Over-instrumentation overhead	Resource waste	Low	Threshold check in audit
Ignored report actions	Persisting gaps	Medium	Integrate into release checklist

14. Estimation Support

1. Audit script
2. Report generation
3. Instrumentation additions
4. Sampling config deploy

15. Analytics / Success Metrics

Span coverage percentage; mean trace latency completeness; number of missing spans over time.

16. Rollout / Release Strategy

Single audit iteration; follow-up tasks scheduled; recurring quarterly.

17. Definition of Ready Checklist

• Critical flow list agreed

18. Definition of Done Checklist

• Report generated & stored
• Instrumentation added
• Sampling config updated

19. Open Questions

1. Automate weekly coverage check?
2. Provide dashboard overlay for gaps?

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Version: 1.0