# Architecture Decision Records

This section contains Architecture Decision Records (ADRs) documenting key architectural decisions and their rationale for the Provisioning platform.

## ADR Index

### Core Architecture Decisions

- **[ADR-001: Modular CLI Architecture](./adr-001-modular-cli.md)** - Decentralized CLI
  registration reducing code by 84%, 80+ keyboard shortcuts, dynamic subcommands.

- **[ADR-002: Workspace-First Architecture](./adr-002-workspace-first.md)** - Workspaces
  as primary organizational unit with isolation boundaries.

- **[ADR-003: Nickel as Source of Truth](./adr-003-nickel-as-source-of-truth.md)** -
  Nickel for type-safe configuration, mandatory validation, KCL migration.

- **[ADR-004: 12-Microservice Architecture](./adr-004-microservice-distribution.md)** -
  Distributed microservices for independent scaling and deployment.

- **[ADR-005: Service Communication](./adr-005-service-communication.md)** - HTTP REST
  for sync operations, message queues for async, pub/sub for events.

### Security and Cryptography

- **[ADR-006: Post-Quantum Cryptography](./adr-006-post-quantum-cryptography.md)** -
  Hybrid encryption: CRYSTALS-Kyber, SPHINCS+, Falcon with AES-256 fallback.

- **[ADR-007: Multi-Layer Data Encryption](./adr-007-data-encryption-strategy.md)** -
  Encryption at-rest, in-transit, field-level, with key rotation policies.

### Operations and Observability

- **[ADR-008: Unified Observability Stack](./adr-008-observability-and-monitoring.md)** -
  Prometheus metrics, ELK Stack, Jaeger distributed tracing.

- **[ADR-009: SLO and Error Budget Management](./adr-009-slo-error-budgets.md)** - Service
  Level Objectives with automatic remediation on SLO violations.

- **[ADR-010: Automated Incident Response](./adr-010-incident-response-automation.md)** -
  Autonomous detection, automatic remediation, escalation, chaos engineering.

## Decision Format

Each ADR follows this structure:

- **Status**: Accepted, Proposed, Deprecated, Superseded
- **Context**: Problem statement and constraints
- **Decision**: The chosen approach
- **Consequences**: Benefits and trade-offs
- **Alternatives**: Other options considered
- **References**: Related ADRs and external docs

## Rationale for ADRs

ADRs document the "why" behind architectural choices:

1. **Modular CLI** - Scales command set without monolithic registration
2. **Workspace-First** - Isolates infrastructure and supports multi-tenancy
3. **Nickel Source of Truth** - Ensures type-safe configuration and prevents runtime errors
4. **Microservice Distribution** - Enables independent scaling and deployment
5. **Communication Protocol** - Balances synchronous needs with async event processing
6. **Post-Quantum Crypto** - Protects against future quantum computing threats
7. **Multi-Layer Encryption** - Defense in depth against data breaches
8. **Observability** - Enables rapid troubleshooting and performance analysis
9. **SLO Management** - Aligns infrastructure quality with business objectives
10. **Incident Automation** - Reduces MTTR and improves system resilience

## Cross-References

These ADRs interact with:

- **Platform Documentation** - See `provisioning/docs/src/architecture/`
- **Features** - See `provisioning/docs/src/features/` for implementation details
- **Development Guides** - See `provisioning/docs/src/development/` for extending systems
- **Security Documentation** - See `provisioning/docs/src/security/` for compliance details
- **Operations Guides** - See `provisioning/docs/src/operations/` for deployment procedures
