# How to Make Cursor Respect Domain Boundaries

- Tool: Cursor
- Difficulty: Beginner
- Time required: 10-15 min
- Compatibility: Cursor Pro+, any language
- Last updated: March 2026

## TL;DR

Make Cursor respect domain-driven design boundaries by mapping your bounded contexts in .cursorrules, creating per-domain rules in nested .cursor/rules/ directories, and using @folder context to scope AI suggestions to specific domains. Without boundary awareness, Cursor freely imports across domains and breaks DDD encapsulation.

## Teaching Cursor About Domain Boundaries

Cursor treats your entire codebase as one flat context by default. It will import a payment utility into an authentication module or reference user types from an order service without hesitation. Domain-driven design requires strict boundaries between bounded contexts, and this tutorial shows you how to encode those boundaries into rules that Cursor respects. You will create domain maps, set up per-domain rules, and learn prompt patterns that keep AI suggestions within the correct domain.

## Before you start

- Cursor installed (Pro recommended for larger projects)
- A project organized by domain or bounded context
- Basic understanding of DDD concepts (bounded contexts, aggregates)

## Step-by-step guide

### 1. Map your bounded contexts in .cursorrules

Document your domain boundaries in .cursorrules so Cursor understands which modules belong to which domain and what cross-domain communication is allowed. List each domain, its directory, and its public API surface.

```
# .cursorrules

## Domain Boundaries (DDD)
### Bounded Contexts
- Auth domain: src/domains/auth/ — handles authentication, sessions, tokens
- Orders domain: src/domains/orders/ — handles order lifecycle, cart, checkout
- Payments domain: src/domains/payments/ — handles payment processing, refunds
- Users domain: src/domains/users/ — handles user profiles, preferences

### Cross-Domain Rules
- Domains communicate ONLY through their public API (index.ts exports)
- NEVER import internal files across domains (no deep imports)
- Shared types go in src/shared/types/ — not duplicated per domain
- Events between domains use src/shared/events/ event bus
- Each domain has its own repository — never query another domain's tables directly
```

> Pro tip: Add a visual directory map to .cursorrules. Cursor reads it and understands the hierarchy better than prose descriptions.

**Expected result:** Cursor understands your domain boundaries and avoids cross-domain imports in generated code.

### 2. Create nested per-domain rules

Place .cursor/rules/ directories inside each domain folder. These rules auto-attach when Cursor is editing files within that domain, reinforcing the boundary without you needing to mention it in every prompt.

```
---
description: Orders domain boundary rules
globs: "src/domains/orders/**"
alwaysApply: false
---

- This is the Orders bounded context
- Only import from: src/domains/orders/**, src/shared/**
- NEVER import from: src/domains/auth/**, src/domains/payments/**, src/domains/users/**
- Communicate with other domains through the event bus: src/shared/events/
- Repository: src/domains/orders/repositories/ — only access orders tables
- Public API: src/domains/orders/index.ts — only these exports are visible to other domains
- Types: use OrderAggregate, OrderItem, OrderStatus from this domain's types/
```

> Pro tip: Nested rules directories auto-attach for files in their parent directory. You do not need glob patterns when using this approach.

**Expected result:** When editing any file in the orders domain, Cursor automatically enforces boundary rules.

### 3. Scope Composer sessions to a single domain

When working within one domain, use @folder to scope Cursor's context. This prevents it from pulling in code from other domains as context. Open Composer with Cmd+I and reference only the relevant domain folder.

```
// Prompt to type in Cursor Composer (Cmd+I):
// @src/domains/orders/ @src/shared/types/
// Add a cancelOrder function to the OrderService.
// Requirements:
// - Only use types and repositories from the orders domain
// - Emit an OrderCancelled event through the shared event bus
// - Do NOT import anything from payments or users domains
// - Update order status to 'cancelled' and record cancellation reason
```

> Pro tip: Start each Composer session by referencing the domain folder and shared types. This sets the context boundary for the entire session.

**Expected result:** Cursor generates code within the orders domain boundary, using only allowed imports.

### 4. Generate domain events for cross-domain communication

When domains need to communicate, use Cursor to generate event-based integration rather than direct imports. Reference both domains' public APIs and the shared event bus to generate proper event publishing and subscription code.

```
// Prompt to type in Cursor Chat (Cmd+L):
// @src/shared/events/eventBus.ts
// @src/domains/orders/index.ts @src/domains/payments/index.ts
// Generate an event flow for order payment:
// 1. Orders domain publishes OrderCreated event with orderId and totalCents
// 2. Payments domain subscribes and initiates payment processing
// 3. Payments domain publishes PaymentCompleted or PaymentFailed event
// 4. Orders domain subscribes and updates order status
// Keep all domain internals encapsulated — only use public API exports.
```

**Expected result:** Cursor generates event definitions, publishers, and subscribers that respect domain boundaries.

## Complete code example

File: `src/domains/orders/.cursor/rules/boundary.mdc`

```markdown
---
description: Orders bounded context rules
globs: "src/domains/orders/**"
alwaysApply: false
---

# Orders Domain Boundary

## Allowed Imports
- `src/domains/orders/**` — all internal modules
- `src/shared/types/**` — shared type definitions
- `src/shared/events/**` — event bus for cross-domain communication
- `src/shared/utils/**` — shared utilities (logging, validation)

## Forbidden Imports
- `src/domains/auth/**` — use events for auth-related flows
- `src/domains/payments/**` — use events for payment flows
- `src/domains/users/**` — use events or shared types for user data

## Public API
Only these exports are visible to other domains:
- `OrderService` — the main service class
- `OrderAggregate` — the order entity type
- `OrderStatus` — the status enum
- `OrderCreated`, `OrderCancelled` — domain events

## Repository Rules
- Only access: orders, order_items, order_history tables
- Never JOIN with tables from other domains
- Use the shared event bus for data from other domains

## Domain Event Patterns
- Publish events for state changes: OrderCreated, OrderUpdated, OrderCancelled
- Subscribe to external events: PaymentCompleted, PaymentFailed
- Events are defined in src/shared/events/orderEvents.ts
```

## Common mistakes

- **Not listing forbidden imports explicitly per domain** — Saying 'respect domain boundaries' is too vague for Cursor. It needs explicit lists of what is allowed and what is forbidden for each domain. Fix: Create per-domain .mdc files with explicit Allowed Imports and Forbidden Imports sections.
- **Using @codebase instead of @folder for domain-scoped work** — @codebase searches the entire project, pulling in code from other domains as context. This pollutes the AI's understanding of boundaries. Fix: Use @folder references scoped to the specific domain directory and shared types only.
- **Sharing database repositories across domains** — If two domains query the same tables, changes in one domain can break the other. This violates DDD's aggregate boundary principle. Fix: Add a rule requiring each domain to own its own tables. Cross-domain data flows through events or API calls, never shared database queries.

## Best practices

- Map all bounded contexts in .cursorrules with directories, allowed imports, and public APIs
- Use nested .cursor/rules/ in each domain directory for auto-attaching boundary enforcement
- Scope Composer sessions with @folder to prevent cross-domain context pollution
- Generate domain events for cross-domain communication instead of direct imports
- Define public API surfaces (index.ts exports) per domain and reference them in rules
- Keep shared types in src/shared/types/ rather than duplicating across domains
- Start new Composer sessions when switching between domains to reset context

## Frequently asked questions

### How does Cursor handle domain boundaries by default?

It does not. Cursor treats your entire codebase as flat context and will freely import across any directory. You must explicitly define boundaries in .cursorrules and per-domain rule files.

### Can Cursor enforce DDD aggregate rules?

Yes, with explicit rules. Define your aggregates, their boundaries, and what can reference them in .cursor/rules/ files. Cursor will follow these constraints when generating code within the domain.

### Should I use one .cursorrules file or per-domain rules?

Both. Use .cursorrules for the global domain map and cross-cutting rules. Use nested .cursor/rules/ directories in each domain for domain-specific constraints. The nested rules auto-attach when editing files in that domain.

### How do I handle shared code between domains?

Create a src/shared/ directory for types, utilities, and the event bus. List it as an allowed import in every domain's rules. Never put domain-specific logic in shared — only truly cross-cutting concerns.

### What if Cursor still imports across domain boundaries?

Rules can drift in long sessions. Start a new chat with Cmd+N and explicitly reference the domain folder with @folder. If the problem persists, copy the boundary rules directly into your prompt.

---

Source: https://www.rapidevelopers.com/cursor-tutorial/how-to-fine-tune-cursor-ai-so-it-respects-domain-driven-design-boundaries
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