# Fail Fast

> A design rule that invalid input or state stops the operation at the point it is detected, with an explicit error.

Record: `architecture:fail-fast`
Kind: principle
Layer: [Correctness Core](https://banes-lab.com/records/layer/correctness-core.md)
Severity: recommended
Scope: input, startup, invariant boundary
Canonical: https://banes-lab.com/ontology#architecture-fail-fast

Listed in [Architecture principles](https://banes-lab.com/api/records/architecture.md), after [Defensive Programming](https://banes-lab.com/records/architecture/defensive-programming.md) and before [Fail Safe](https://banes-lab.com/records/architecture/fail-safe.md).

## Repair

- Refactored by: Add Guard Clause, Throw Explicit Error
- Detected by: ignored exceptions, default fallbacks masking errors
- Violated by: swallowing invalid state
- Measured by: late failure rate
- Enforced by: validation tests

## Requires

- [Preconditions](https://banes-lab.com/records/architecture/preconditions.md)
- [Validation](https://banes-lab.com/records/architecture/validation.md)

## Reinforces

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

## Enables

- [Early Defect Detection](https://banes-lab.com/records/lexicon/early-defect-detection.md)

## Conflicts with

- [Silent Failure](https://banes-lab.com/records/lexicon/silent-failure.md)
- [Silent Data Corruption](https://banes-lab.com/records/architecture/silent-data-corruption.md)

## In tension with

- [Graceful Degradation](https://banes-lab.com/records/architecture/graceful-degradation.md)

## Tensions

- [Fail Fast / Graceful Degradation](https://banes-lab.com/records/tension/fail-fast-graceful-degradation.md)

## Contracts

- [Correctness Core](https://banes-lab.com/records/algorithms/correctness-core.md)

## Severity

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

## Category

- [Error Handling / Resilience](https://banes-lab.com/records/architecture-category/error-handling-resilience.md)

## Enforced by

- [rules/eslint/strings-diagram-identifiers.eslint.rule.ts](https://banes-lab.com/source/governance/rules/eslint/strings-diagram-identifiers.eslint.rule.ts.md)
- [rules/stylelint/no-unresolved-import.stylelint.rule.ts](https://banes-lab.com/source/governance/rules/stylelint/no-unresolved-import.stylelint.rule.ts.md)

## Reinforced by

- [Defensive Programming](https://banes-lab.com/records/architecture/defensive-programming.md)

## Enabled by

- [Schema Validation](https://banes-lab.com/records/architecture/schema-validation.md)
- [Input Validation](https://banes-lab.com/records/architecture/input-validation.md)

## Linked from

- [Validation gates](https://banes-lab.com/pag/validation/validation-gates.md)
- [The gate holds the line](https://banes-lab.com/disciplined-methodology/build/the-gate-holds-the-line.md)
- [Fail at the boundary](https://banes-lab.com/disciplined-methodology/build/fail-at-the-boundary.md)
- [Every record has a kind](https://banes-lab.com/software-architecture/principles/every-record-has-a-kind.md)
- [Execution joins the halves](https://banes-lab.com/software-architecture/principles/execution-joins-the-halves.md)
- [A tension has a mechanism](https://banes-lab.com/software-architecture/principles/a-tension-has-a-mechanism.md)
- [Separate, trade, or mitigate](https://banes-lab.com/software-architecture/principles/separate-trade-or-mitigate.md)
- [Debt and leverage](https://banes-lab.com/software-architecture/decay/debt-and-leverage.md)
- [The principle architecture](https://banes-lab.com/software-architecture/glossary/the-principle-architecture.md)
- [Architectural rules and principles](https://banes-lab.com/software-architecture/glossary/architectural-principles.md)
- [Anti-patterns](https://banes-lab.com/ontology/principles/architecture-category-anti-patterns.md)
- [Contracts / Interfaces / Compatibility](https://banes-lab.com/ontology/principles/architecture-category-contracts-interfaces-compatibility.md)
- [Correctness / Determinism / Verification](https://banes-lab.com/ontology/principles/architecture-category-correctness-determinism-verification.md)
- [Error Handling / Resilience](https://banes-lab.com/ontology/principles/architecture-category-error-handling-resilience.md)
- [Observability / Auditability / Traceability](https://banes-lab.com/ontology/principles/architecture-category-observability-auditability-traceability.md)
- [Schema / Canonical Data / Semantics](https://banes-lab.com/ontology/principles/architecture-category-schema-canonical-data-semantics.md)
- [Security / Privacy / Compliance / Governance](https://banes-lab.com/ontology/principles/architecture-category-security-privacy-compliance-governance.md)
- [Core Vocabulary](https://banes-lab.com/ontology/lexicon/lexicon-category-core-vocabulary.md)
- [Error Handling / Resilience](https://banes-lab.com/ontology/lexicon/lexicon-category-error-handling-resilience.md)
- [Architectural Clusters](https://banes-lab.com/ontology/algorithms/algorithms-domain-architectural-clusters.md)
- [Severity levels](https://banes-lab.com/ontology/schema/the-vocabulary-severity.md)
- [The resolutions](https://banes-lab.com/ontology/schema/the-resolutions.md)