Arch Domains

Role

Owns all business rules — session lifecycle, agent execution, pipeline orchestration, analysis, and tooling. Never touches raw I/O (files, processes, APIs) directly; always delegates to repository interfaces or functions.

Import Rules

Injection Styles

Style A — interface injection (repository is class-based with IXxxRepository)

import type { ISessionRepository } from '@src/repositories/ports/session'

export class SessionDomain implements ISessionDomain {
  constructor(private sessionRepo: ISessionRepository) {}  // inject interface, not concrete class
}

Style B — function-based (repository exposes plain exported functions)

import { saveSession, loadSession } from '@src/repositories/sessions'

export class SomeDomain implements ISomeDomain {
  constructor(private dir: string) {}
  async get(id: string) { return loadSession(this.dir, id) }
}

Choose Style A when the repository is a class; Style B when it exposes plain functions. Never call filesystem APIs or spawn processes directly.

Port Placement

• Domain ports → src/domains/ports/<name>.ts (consumed by services/)
• Repository ports → src/repositories/ports/<name>.ts (consumed by domains/)
• Never define IXxx inside a domain implementation file

Intra-Domain Composition

Inject other domains by their port type from domains/ports/, never the concrete class:

import type { ISessionDomain } from '@src/domains/ports/session'

export class AnalyzeDomain implements IAnalyzeDomain {
  constructor(private sessionDomain: ISessionDomain) {}  // ✓ port type
}
// ✗ Bad: import { SessionDomain } from '@src/domains/session' + new SessionDomain(...)

A domain with pure business logic may inject only other domain ports and no repository — both patterns are valid.

Prohibitions

• Never import from cli, services, or infrastructures
• Never import zod — validation belongs in validators/
• Never access the filesystem, spawn processes, or call external APIs directly
• Never read process.env
• Never expose transport variants in a repository port — single abstract method only
• Never define IXxx in a domain implementation file
• Never import or instantiate a concrete repository class (new XxxRepository())
• Never call into services/ — domains sit below services in the dependency chain

References

• references/session-field-migration.md — lazy normalize() pattern for renaming a persisted session JSON field