# Unobservable Failure

> A defect in which an operation can fail without leaving a log, metric, trace or error contract.

Record: `architecture:unobservable-failure`
Kind: anti-pattern
Layer: [Enforcement Core](https://banes-lab.com/records/layer/enforcement-core.md)
Severity: discouraged
Scope: contract_compatibility
Aliases: Opaque System
Canonical: https://banes-lab.com/ontology#architecture-unobservable-failure

Listed in [Architecture principles](https://banes-lab.com/api/records/architecture.md), after [Unowned Risk](https://banes-lab.com/records/architecture/unowned-risk.md) and before [Unversioned Breaking Change](https://banes-lab.com/records/architecture/unversioned-breaking-change.md).

## Repair

- Refactored by: add_error_boundary, emit_structured_log, add_metric, add_alert, add_trace_span, add_audit_log
- Detected by: empty_catch, swallowed_exception, missing_error_log, no_alert_on_critical_path, missing_trace_span, missing_audit_record
- Violated by: Permit operations to fail without structured logs, metrics, alerts, traces, audit records, or user-visible error contracts.
- Measured by: swallowed exceptions, critical paths without error telemetry
- Enforced by: lint rules against empty and swallowing catch blocks, telemetry coverage checks

## Severity

- [discouraged](https://banes-lab.com/records/vocabulary/severity-discouraged.md)

## Category

- [Anti-patterns](https://banes-lab.com/records/architecture-category/anti-patterns.md)

## Force

- [Contract compatibility](https://banes-lab.com/records/force/contract-compatibility.md)

## Detected by

- [rules/eslint/no-swallowed-failure.eslint.rule.ts](https://banes-lab.com/source/governance/rules/eslint/no-swallowed-failure.eslint.rule.ts.md)
- [rules/eslint/require-signal-guard.eslint.rule.ts](https://banes-lab.com/source/governance/rules/eslint/require-signal-guard.eslint.rule.ts.md)

## Negated by

- [Observability](https://banes-lab.com/records/architecture/observability.md)

## Linked from

- [Seven controls, seven classes](https://banes-lab.com/software-architecture/decay/seven-controls-seven-classes.md)
- [Anti-patterns](https://banes-lab.com/ontology/principles/architecture-category-anti-patterns.md)
- [Observability / Auditability / Traceability](https://banes-lab.com/ontology/principles/architecture-category-observability-auditability-traceability.md)
- [Failure shapes](https://banes-lab.com/ontology/reasoning/the-failure-shapes.md)
- [Severity levels](https://banes-lab.com/ontology/schema/the-vocabulary-severity.md)
- [The forces](https://banes-lab.com/ontology/schema/the-forces.md)