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Architecture Patterns

Python architecture standards (Hexagonal + DDD + CQRS), teaching-edition walkthroughs, and domain-specific playbooks for building well-structured LLM agent frameworks.


Key Findings

  • Hexagonal Architecture + DDD + CQRS combined pattern provides clear boundary enforcement for LLM agent frameworks
  • Zero-dependency domain layer is the critical architectural constraint — domain logic must not import from infrastructure or interface layers
  • Port/adapter pattern enables infrastructure swapping (database, LLM provider, CLI) without touching domain or application logic
  • Teaching editions prove the patterns are learnable — the Work Tracker Architecture walkthrough demonstrates the full stack

Python Architecture Standards

The authoritative architecture reference for the Jerry Framework, defining layer boundaries, dependency directions, and anti-patterns.

Methodology

Synthesized from Hexagonal Architecture (Cockburn, 2005), Domain-Driven Design (Evans, 2003), and CQRS (Young, 2010) into a unified Python-specific standard. Layer boundaries validated through dependency analysis and anti-pattern detection across the Jerry codebase.

Key Data
  • DDD + Hexagonal + CQRS combined pattern
  • Dependency direction rules: Domain ← Application ← Infrastructure/Interface
  • Zero-dependency domain: HARD constraint (H-07)
  • Port/adapter boundaries with naming conventions
  • Anti-patterns catalog with remediation guidance
  • One-class-per-file rule (H-10) with CQRS naming conventions

Python Architecture Standards (645 lines)


Work Tracker Architecture: Teaching Edition

A teaching-edition walkthrough of the Hexagonal DDD CQRS architecture applied to a real bounded context in the Jerry Framework.

Methodology

Applied the Python Architecture Standards to the Work Tracker bounded context. Each layer is built incrementally (domain → application → infrastructure → interface) with concrete code examples and explanations of architectural decisions at each step.

Key Data
  • 1,049 lines of educational walkthrough
  • Layered architecture with concrete code examples
  • DDD bounded contexts applied to work tracking domain
  • CQRS pattern implementation with command/query separation
  • Step-by-step progression from domain → application → infrastructure

Teaching Edition (1,049 lines)


Domain-Specific Playbooks

Reference playbooks for applying architecture patterns to specific bounded contexts.

Methodology

Extracted recurring patterns from bounded context implementations across the Jerry Framework. Each playbook provides domain-specific guidance for applying Hexagonal DDD CQRS to a particular problem space.

Key Data
  • 315 lines of domain-specific reference material
  • Bounded context identification and boundary mapping
  • Aggregate root selection patterns per domain
  • Repository and port naming conventions by context
  • Anti-pattern examples specific to each domain

Domain Playbooks (315 lines)