Error propagation scenarios: 11 cross-object failure paths

[AlexMikhalev]

Parent: #39

Context

The scenario derivation pipeline identified 11 error scenarios where cross-object propagation can fail. These represent failure paths from the 5 business scenarios (BS-001 through BS-005) and should be tested to ensure graceful degradation.

Error Scenarios

ID	Event	Failing Propagation	Severity
SC-ERR-001	genomic_report_received	entity extraction fails to identify variants	Critical
SC-ERR-002	genomic_report_received	SNOMED CT mapping fails	Critical
SC-ERR-003	entity_extraction_complete	MedGemma recommendation generation fails	Critical
SC-ERR-004	recommendation_generated	evidence retrieval from CORD-19 fails	High
SC-ERR-005	recommendation_blocked	alternative recommendation generation fails	High
SC-ERR-006	treatment_plan_finalized	case outcome tracking fails	Medium
SC-ERR-007	drug_interaction_detected	CPIC dose adjustment fails	Critical
SC-ERR-008	dose_adjustment_recommended	PGx audit logging fails	Medium
SC-ERR-009	neoantigen_predicted	vaccine design candidate ranking fails	High
SC-ERR-010	vaccine_design_complete	patient case monitoring flag fails	Medium
SC-ERR-011	trial_match_found	trial-case association fails	Medium

Mapping to Business Scenario Failure Paths

Error	BS Failure Path
SC-ERR-001	BS-001 FL-3: Entity extraction failure (<80% extracted)
SC-ERR-002	BS-001 FL-2: Knowledge graph query failure
SC-ERR-003	BS-001 FL-1: MedGemma inference timeout (>30s)
SC-ERR-004	BS-001 FL-2: KG unavailable, limited evidence
SC-ERR-007	BS-002 FL-2: Drug database sync failure

Implementation Notes

• Critical errors (SC-ERR-001, 002, 003, 007) must have fallback paths
• BS-001 specifies: MedGemma timeout -> fallback to NCCN guideline lookup
• BS-001 specifies: KG failure -> fallback to direct literature search
• BS-002 specifies: Drug DB failure -> external database lookup
• Each error should produce a user-facing message matching the BS failure path specification
• These should be implemented as integration tests exercising the full pipeline with injected failures

[AlexMikhalev]

Error Propagation Scenarios (11 total)

These test cross-object failure paths from business events. When an event fires and one propagation step fails, downstream steps should not execute.

SC-ERR-001: genomic_report_received fails at entity extraction

• Event: Genomic Report Received
• Failing step: genomic_variant -- entity extraction identifies variants from report text
• Expected: Downstream SNOMED mapping does not execute, failure detected
• Service: entity_extraction_service
• Related issues: Implement genomic report processing pipeline (genomic_report_processing) #41 (genomic report processing)

SC-ERR-002: genomic_report_received fails at SNOMED mapping

• Event: Genomic Report Received
• Failing step: snomed_concept -- extracted entities mapped to SNOMED CT concepts
• Prerequisite: Step 1 (entity extraction) succeeds
• Expected: SNOMED mapping failure detected, partial results handled
• Service: entity_extraction_service
• Related issues: Implement genomic report processing pipeline (genomic_report_processing) #41

SC-ERR-003: entity_extraction_complete fails at recommendation trigger

• Event: Entity Extraction Complete
• Failing step: recommendation -- triggers AI recommendation generation via MedGemma
• Expected: Downstream recommendation generation halted, failure logged
• Service: clinical_reasoning_service
• Related issues: Implement recommendation validation state machine #42 (recommendation validation)

SC-ERR-004: recommendation_generated fails at evidence retrieval

• Event: Recommendation Generated
• Failing step: evidence -- evidence links retrieved from CORD-19 and literature
• Expected: Recommendation flagged for review (cannot validate without evidence)
• Service: evidence_service
• Related issues: Implement recommendation validation state machine #42, Implement evidence retrieval service (replace stub) #47 (evidence service)

SC-ERR-005: recommendation_blocked fails at alternative generation

• Event: Recommendation Blocked
• Failing step: recommendation -- alternative recommendations generated with adjusted ranking
• Expected: Original blocked recommendation stays blocked, no alternatives available
• Service: clinical_reasoning_service
• Related issues: Implement recommendation validation state machine #42

SC-ERR-006: treatment_plan_finalized fails at case tracking

• Event: Treatment Plan Finalized
• Failing step: patient_case -- case flagged for outcome tracking
• Expected: Plan stays finalized, tracking gap detected and alerted
• Service: clinical_reasoning_service
• Related issues: Implement treatment plan lifecycle state machine #43 (treatment plan)

SC-ERR-007: drug_interaction_detected fails at dose adjustment

• Event: Drug Interaction Detected
• Failing step: dose_adjustment -- CPIC guideline rules applied for recommended dose modification
• Expected: Interaction detected but dose recommendation unavailable, pharmacist alerted
• Service: pharmacogenomics_service

SC-ERR-008: dose_adjustment_recommended fails at PGx logging

• Event: Dose Adjustment Recommended
• Failing step: pgx_variant -- PGx rationale logged for audit compliance
• Expected: Dose adjustment delivered but audit trail incomplete, compliance alert raised
• Service: pharmacogenomics_service

SC-ERR-009: neoantigen_predicted fails at vaccine design ranking

• Event: Neoantigen Predicted
• Failing step: vaccine_design -- ranked candidates available for researcher selection
• Expected: Neoantigen predictions available but ranking/selection UI unavailable
• Service: vaccine_design_service
• Related issues: Implement vaccine design pipeline and status lifecycle #44 (vaccine pipeline)

SC-ERR-010: vaccine_design_complete fails at immune monitoring

• Event: Vaccine Design Complete
• Failing step: patient_case -- case flagged for immune response monitoring
• Expected: Design finalized but monitoring gap detected
• Service: vaccine_design_service
• Related issues: Implement vaccine design pipeline and status lifecycle #44

SC-ERR-011: trial_match_found fails at case association

• Event: Trial Match Found
• Failing step: patient_case -- matching trials associated with patient case for physician review
• Expected: Match results preserved, case association retried
• Service: trial_matching_service
• Related issues: Implement clinical trial matching service #45 (trial matching)

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Implementation Pattern

For each error scenario, implement:

#[test]
fn test_sc_err_NNN_event_propagation_failure() {
    // 1. Set up preconditions (event triggered)
    // 2. Simulate failure at the specific propagation step
    // 3. Assert downstream steps did NOT execute
    // 4. Assert failure was detected and logged
    // 5. Assert appropriate fallback behavior
}

Key patterns:

• Use Result<T, E> chains for propagation steps
• Each step should be independently testable
• Failure at step N should prevent steps N+1..M from executing
• All failures should be logged with the event ID and step number