58 lines
2.9 KiB
Markdown
58 lines
2.9 KiB
Markdown
# Boundary Rules
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Hard constraints for every implementation phase. Violations block completion.
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Canonical ownership: [module-boundaries.md](../architecture/module-boundaries.md). Process mandate: [ADR-018](../architecture/adr/ADR-018.md).
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## Service & Module Boundaries
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1. **Never implement responsibilities owned by another service.**
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2. **Never duplicate business logic** that already lives in an owning service — consume it.
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3. **Never access another service’s database** (no cross-DB queries, FKs, or shared schemas).
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4. **Integrate only through** versioned HTTP APIs, domain/integration Events, and Provider interfaces.
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5. **Never import** another service’s models, repositories, or private modules.
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## Phase Boundaries
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1. **Never move functionality from future phases into the current phase.**
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2. **Never silently expand Scope** into adjacent modules “while we’re here.”
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3. **Out of Scope is binding** — document exclusions and respect them.
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4. High-level roadmap text authorizes **deriving production engineering** for the current phase ([definition-of-done.md](definition-of-done.md), [enterprise-phase-discovery.md](enterprise-phase-discovery.md)), **not** pulling next-phase product features forward.
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## Data & Logic Boundaries
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| Allowed | Forbidden |
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| --- | --- |
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| External ID / ref fields (`*_ref`) | Cross-service foreign keys |
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| HTTP clients to published APIs | Reading foreign ORM models |
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| Outbox → event bus → consumers | Dual-writing the same journal/aggregate in two services |
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| Provider adapters in the **owning** service | Implementing SMS/payment/etc. inside a non-owning vertical |
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| Shared-lib envelopes/exceptions/JWT helpers | Shared-lib business workflows |
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## Accounting & Platform Specials
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1. Journal entries only via Accounting Posting Engine ([ADR-010](../architecture/adr/ADR-010.md)).
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2. Messaging providers only inside Communication ([ADR-012](../architecture/adr/ADR-012.md)).
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3. Product AI remains optional and independent ([ai-architecture.md](../architecture/ai-architecture.md)).
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4. Public-surface cross-service attachments use **`publish_id`** only ([ADR-022](../architecture/adr/ADR-022.md)) — never Experience/vertical internal tables as the integration key.
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## Frontend / Backend
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1. UI only under `frontend/` ([ADR-002](../architecture/adr/ADR-002.md)).
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2. Backend never embeds UI rules as the source of truth.
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3. Frontend never imports backend packages.
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## Enforcement
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- Architecture Validation stage ([development-loop.md](development-loop.md))
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- Architecture / Integration gates ([quality-gates.md](quality-gates.md))
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- Architecture tests in the service suite ([testing-template.md](testing-template.md))
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## Related Documents
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- [Module Boundaries](../architecture/module-boundaries.md)
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- [Enterprise Phase Discovery](enterprise-phase-discovery.md)
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- [Master Prompt](master-prompt.md)
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- [Service Template](service-template.md)
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- [Module Template](module-template.md)
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