Summary

Document container_system's minimal dependency architecture as a reference pattern for other modules in the ecosystem.

5W1H Specification

• Who: container_system maintainers, ecosystem documentation
• What: Create documentation describing container_system's clean dependency model
• Where: docs/ARCHITECTURE.md, README.md
• When: v0.4.0.0 release cycle
• Why:
  • container_system has the cleanest dependency structure (only common_system)
  • Other modules can learn from this pattern
  • Supports ecosystem-wide architectural consistency
• How: Document current architecture as a reference implementation

Priority

LOW - Documentation task, no code changes required

Current State Analysis

container_system represents the ideal dependency pattern:

container_system
       │
       ▼
common_system (ONLY dependency)

Dependency Characteristics

Key Files Demonstrating Pattern

Documentation Structure

Proposed docs/ARCHITECTURE.md Sections

1. Dependency Philosophy

   • Why minimal dependencies matter
   • How container_system achieves isolation

2. Integration Patterns

   • How other modules integrate with container_system
   • Messaging integration example

3. External Dependencies

   • gRPC (external, optional)
   • Protobuf (external, optional)

4. Build Configuration

   • Minimal build
   • With gRPC support
   • With messaging integration

Tasks

• Create docs/ARCHITECTURE.md with dependency philosophy
• Document why only common_system is required
• Add dependency diagram to README
• Document gRPC as external (not ecosystem) dependency
• Create "minimal dependency" checklist for other modules
• Add links to this doc from ecosystem CROSS_MODULE_INTEGRATION.md

Reference Pattern Checklist

For other modules to achieve similar minimal dependency:

## Minimal Dependency Checklist

- [ ] Only depend on lower-tier modules (common_system for Tier 1)
- [ ] Use interfaces from common_system instead of direct module dependencies
- [ ] External dependencies (gRPC, OpenSSL) are NOT ecosystem dependencies
- [ ] All optional ecosystem integrations use conditional compilation
- [ ] Module can build and test with only required dependencies
- [ ] No circular dependency risk (only depends downward)

Acceptance Criteria

• docs/ARCHITECTURE.md exists and explains dependency model
• README includes dependency diagram
• Checklist can be used by other modules
• Linked from ecosystem documentation

Dependencies

• None - Documentation only

Parent Epic

• Epic: Cross-Module Circular Dependency Resolution common_system#232