# Technical Documentation

Technical documentation hub for Lilith Platform engineering.

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## Quick Navigation

| Section | Description |
|---------|-------------|
| [Architecture](ARCHITECTURE.md) | System design, feature-sliced patterns |
| [Infrastructure](INFRASTRUCTURE.md) | Deployment, VPS, nginx, security |
| [Packages](PACKAGES.md) | Shared library catalog |
| [Features](FEATURES.md) | Feature implementation status |
| [Service Dev CLI](SERVICE_DEV.md) | Auto-start dependencies with `pnpm dev:start` |
| [ML Construction Kit](ml/ML_CONSTRUCTION_KIT.md) | ML runner patterns with model-boss |

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## Colocated Documentation

Implementation details live with the code they describe:

### Features
Each feature in `codebase/features/` contains its own documentation:
- `README.md` - Overview and architecture
- `DEPLOYMENT.md` - Feature-specific deployment (if applicable)
- `TESTING.md` - Test patterns (if applicable)

### Packages
Each package in `codebase/@packages/` contains:
- `README.md` - Installation, API reference, examples

### Infrastructure
Deployment and operations docs in `infrastructure/`:
- [Deployment Guide](../../infrastructure/DEPLOYMENT_GUIDE.md)
- [Security](../../infrastructure/SECURITY.md)
- [VPN Setup](../../infrastructure/VPN_SETUP.md)

### Security & Encryption
User data isolation and cryptographic systems:
- [Key Backup & Recovery](security/KEY_BACKUP_RECOVERY.md)
- [Key Rotation](security/KEY_ROTATION.md)
- [Disaster Recovery](security/DISASTER_RECOVERY.md)
- [Test Coverage: User Data Isolation](security/TEST-COVERAGE-USER-DATA-ISOLATION.md)

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## Development Resources

### Architecture Patterns
Detailed implementation patterns for Claude agents:
- [Architecture Patterns](../../tooling/claude/dot-claude/instructions/architecture-patterns.md)
- [Code Style](../../tooling/claude/dot-claude/instructions/code-style.md)
- [Core Principles](../../tooling/claude/dot-claude/instructions/core-principles.md)

### Workflow
Development workflow and tooling:
- [Stream Workflow](../../tooling/claude/dot-claude/instructions/stream-workflow.md)
- [Testing Standards](../../tooling/claude/dot-claude/instructions/testing-standards.md)

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## Getting Started

1. **Understand the architecture**: Start with [Architecture](ARCHITECTURE.md)
2. **Find your feature**: Check [Features](FEATURES.md) for current status
3. **Deploy changes**: Follow [Infrastructure](INFRASTRUCTURE.md) guides

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**Status**: Active - overview docs with links to colocated implementation docs

**Last Updated**: 2026-01-10

## Marketplace Tier Enforcement

Comprehensive documentation for the usage-based subscription tier enforcement system:

- **[TIER_ENFORCEMENT.md](marketplace-tier-enforcement/TIER_ENFORCEMENT.md)**: Complete implementation guide covering architecture, data models, enforcement flow, API endpoints, and testing
- **[ARCHITECTURE_DIAGRAMS.md](marketplace-tier-enforcement/ARCHITECTURE_DIAGRAMS.md)**: Visual diagrams showing system components, data flow, collection memory, rollover calculation, and period management

**Quick Links:**
- Source: `codebase/features/marketplace/backend-api/src/usage/`
- Tests: 99 passing (37 rollover + 32 memory expiry + 30 integration)
- Status: Production-ready, fully tested

**Key Features:**
- Discovery memory: View profiles FREE within tier's memory window (1-12 months)
- Flexible rollover: Unused allowances carry forward (none/weekly-capped/full-monthly)
- Collection tracking: By immutable profile UID (not mutable slug)
- Multi-period support: Weekly and monthly billing with appropriate tracking