## Introduction

# Introduction

This document defines the requirements and current system limitations for order management and bulk order import functionality in the target Spring Boot system. The content is based exclusively on validated business needs, technical constraints, and architectural boundaries as documented for the migration from the legacy system.

## Background and Purpose

The current order management system requires that each order be created individually, either via REST API or through the administrative interface. There is significant demand from corporate customers to support bulk order creation—specifically, the ability to import large volumes of orders (ranging from 100 to 10,000) via CSV file upload. The primary business objective is to improve operational efficiency and support the business processes of corporate clients through enhanced order processing capabilities. However, the existing system architecture imposes strict limitations on bulk operations, which must be clearly understood and addressed in any future enhancements. [KB-155b5f4a-d232-4166-bb96-ba158f86ceb1], [KB-1603dccf-0e13-426d-a4c3-527af9e69c16], [KB-161f44bf-9450-491f-b894-1fd70c185060]

## Scope

This section covers:

- The current business requirements for bulk order import and order management.
- The technical and architectural constraints that define the system boundaries.
- The impact of these limitations on business operations and user experience.

## Key Limitations

The following limitations are critical to understanding the current system's capabilities:

| ID      | Limitation                                                                                                 | Impact Area          | Severity   |
|---------|------------------------------------------------------------------------------------------------------------|----------------------|------------|
| LIM-001 | **Order creation is single-entry only.** No bulk or batch order creation capability exists. Orders can only be created one at a time via the REST API. | Order Service        | High       |
| LIM-002 | **No CSV/file-based order import functionality.** There is no endpoint or mechanism to upload and process order data from files (CSV, Excel, etc.). | Order Service        | High       |
| LIM-003 | **Payment processing handles one transaction at a time.** No batch payment API exists. Each order requires an individual payment API call. | Payment Service      | High       |
| LIM-004 | **Notifications are sent individually per order.** No bulk notification capability exists. Each notification requires a separate API call. | Notification Service | Medium     |
| LIM-005 | **Cross-service calls are sequential.** Order creation flow (Order → Payment → Notification) executes sequentially. No parallel processing of payment and notification. | All Services         | Medium     |
| LIM-006 | **No progress tracking for batch operations.** The system has no mechanism to track progress of multi-item operations because no batch operations exist. | All Services         | Medium     |

[KB-146a6a29-932f-485d-96d6-6a92ee610336], [KB-0a36efdc-f63e-4c6b-8191-220e34d8af3f], [KB-0a7d4d64-4d48-4214-94eb-2f3f278ec66a]

## Business Justification

The enhancement of order management capabilities, particularly bulk order import via CSV, is expected to significantly improve operational efficiency for corporate clients. However, any such enhancement must address the architectural and technical constraints outlined above to ensure system reliability, maintainability, and performance. [KB-155b5f4a-d232-4166-bb96-ba158f86ceb1], [KB-1603dccf-0e13-426d-a4c3-527af9e69c16], [KB-161f44bf-9450-491f-b894-1fd70c185060]

## Document Organization

Subsequent sections will detail the business requirements, technical constraints, data model considerations, and compliance requirements for order management and bulk import functionality. All requirements and constraints are derived strictly from the provided source materials.

## Getting Started

# 2. Getting Started

## 2.1 System Overview

The current order management system is a web-based application utilizing a React single-page application (SPA) frontend, which connects to three backend microservices via REST API. All inter-service communication is synchronous REST over HTTP, with no message brokers or asynchronous channels present. The system is designed for single-order entry and does not support bulk or batch order creation, CSV/file-based import, or batch payment/notification processing. Each order, payment, and notification is processed individually and sequentially. There is no real-time dashboard update; all statistics are calculated client-side. The system interface and notifications are in Japanese only, with no internationalization framework implemented. [KB-050d0be4-11bc-4945-80c9-1e3a1a2c7685cc], [KB-0d7daadd-e958-4592-900a-55db91f8aa55], [KB-0a36efdc-f63e-4c6b-8191-220e34d8af3f], [KB-146a6a29-932f-485d-96d6-6a92ee610336], [KB-16181d30-2dd3-421e-bab0-939cd85255d2], [KB-0a7d4d64-4d48-4214-94eb-2f3f278ec66a], [KB-017cfb36-5c85-4f93-92bd-6bb395022c54]

## 2.2 Key Functional Limitations

| Limitation ID | Description                                                                                      | Impact Area         | Severity |
|---------------|--------------------------------------------------------------------------------------------------|---------------------|----------|
| LIM-001       | Order creation is single-entry only. No bulk or batch order creation capability exists.           | Order Service       | High     |
| LIM-002       | No CSV/file-based order import functionality.                                                     | Order Service       | High     |
| LIM-003       | Payment processing handles one transaction at a time. No batch payment API exists.                | Payment Service     | High     |
| LIM-004       | Notifications are sent individually per order. No bulk notification capability exists.            | Notification Service| Medium   |
| LIM-005       | Cross-service calls are sequential. No parallel processing of payment and notification.           | All Services        | Medium   |
| LIM-006       | No progress tracking for batch operations.                                                        | All Services        | Medium   |
| LIM-007       | No real-time dashboard updates; statistics are calculated in the browser.                         | Dashboard           | Medium   |
| LIM-008       | Single-language (Japanese); no i18n framework.                                                    | UI/Notifications    | Low      |

[KB-146a6a29-932f-485d-96d6-6a92ee610336], [KB-0a36efdc-f63e-4c6b-8191-220e34d8af3f], [KB-017cfb36-5c85-4f93-92bd-6bb395022c54]

## 2.3 Order Management Interface

- **BulkImportBanner**: An amber warning is displayed indicating that CSV import is not available.
- **CSV Import Button**: The button is present but disabled, labeled “CSVインポート（未実装）” (“CSV Import (Not Implemented)”).
- **Order Creation**: Orders can only be created one at a time via the single order creation form.
- **Order Detail View**: For each order, data is fetched from all three backend services in parallel (Order, Payment, Notification) and displayed, including order details, payment card, and notification history.
- **Search/Filter**: Client-side filtering by customer name/email and status is available.
- **Cancel Order**: Orders can be cancelled with a confirmation dialog; this triggers a refund and a cancellation notification.

[KB-16181d30-2dd3-421e-bab0-939cd85255d2]

## 2.4 API and Data Model Constraints

- All order, payment, and notification APIs are designed for single-entity operations only.
- There are no endpoints for bulk creation, update, or deletion.
- Each payment must be processed individually, with a maximum amount of 1,000,000 JPY per transaction.
- Each notification is sent individually, with a rate limit of 10 notifications per second.
- There are no database schema fields (e.g., batch_id, csv_source, bulk_import_group) to track batch imports or group orders.
- No retry or circuit breaker mechanisms are implemented for cross-service API calls; failures are logged, and the order status is reverted to pending.
- No progress tracking exists for multi-item operations.

[KB-0a7d4d64-4d48-4214-94eb-2f3f278ec66a], [KB-146a6a29-932f-485d-96d6-6a92ee610336], [KB-0f930ddc-3571-41cc-9240-3ef463769553], [KB-04a84995-0820-4319-c1582821058a], [KB-05b70fbd-4026-4ac9-b1e2-e21dabe7da5c], [KB-150eb89c-77b0-415b-a547-3ed0502eec24], [KB-11739ab0-b209-41e4-b73e-7d7e0c4338b2], [KB-01305cb3-d331-4b4b-ba02-69ada467b41d], [KB-033639ab-c6f8-4f72-a373-bf76d05dd6cf]

## 2.5 Getting Support

For questions or issues regarding system limitations, feature requests, or operational guidance, please contact the system administrator or refer to the internal documentation. Architectural changes to enable bulk import or batch processing will require significant cross-service modifications and are not supported in the current release.

[GAP: Missing data for Getting Started — user onboarding, authentication, and initial setup instructions]

---

**References:**  
[KB-050d0be4-11bc-4945-80c4-1e3a1a2c7685cc]  
[KB-0d7daadd-e958-4592-900a-55db91f8aa55]  
[KB-0a36efdc-f63e-4c6b-8191-220e34d8af3f]  
[KB-146a6a29-932f-485d-96d6-6a92ee610336]  
[KB-16181d30-2dd3-421e-bab0-939cd85255d2]  
[KB-0a7d4d64-4d48-4214-94eb-2f3f278ec66a]  
[KB-017cfb36-5c85-4f93-92bd-6bb395022c54]  
[KB-0f930ddc-3571-41cc-9240-3ef463769553]  
[KB-04a84995-0820-4319-c1582821058a]  
[KB-05b70fbd-4026-4ac9-b1e2-e21dabe7da5c]  
[KB-150eb89c-77b0-415b-a547-3ed0502eec24]  
[KB-11739ab0-b209-41e4-b73e-7d7e0c4338b2]  
[KB-01305cb3-d331-4b4b-ba02-69ada467b41d]  
[KB-033639ab-c6f8-4f72-a373-bf76d05dd6cf]

## Build and Test

# 8. Build and Test

This section describes the build and test processes, requirements, and constraints for the system, as required by ISO/IEC/IEEE 29148. All content is strictly derived from the provided context.

---

## 8.1 Build Process

### 8.1.1 Technology Stack

The target system is implemented using the following technology stack:

| Component            | Technology                      | Version      | End of Life                   |
|----------------------|---------------------------------|--------------|-------------------------------|
| Programming Language | Java (Spring Boot)              | 6.x          | N/A                           |
| ORM / Data Access    | Spring Data JPA + Hibernate     | 6.4          | N/A                           |
| Database             | PostgreSQL                      | 16 (AWS RDS) | N/A                           |
| Authentication       | Spring Security + OAuth 2.0     | 6.x          | N/A                           |
| Frontend             | React (SPA)                     | N/A          | N/A                           |
| Reporting            | JasperReports                    | N/A          | N/A                           |
| Audit Logging        | PostgreSQL, CloudWatch, Elasticsearch | N/A    | N/A                           |
| Containerization     | ECS Fargate                      | N/A          | N/A                           |
| Data Encryption      | AWS KMS, AES-256-GCM            | N/A          | N/A                           |
| File Storage         | AWS S3 (SSE-KMS)                | N/A          | N/A                           |
| TLS                  | TLS 1.3                         | N/A          | N/A                           |

[KB-17a58f06-2387-412d-bf37-2f4d751e1d7e], [KB-0e90d327-2678-405f-b35a-294b5435dc66], [KB-1a54c453-d6ee-488f-bbdc-311c467a9661], [KB-116f84fb-2eec-4493-9762-414a92624981]

---

### 8.1.2 Build Automation and Artifacts

- All code is built and packaged using standard CI/CD pipelines.
- OWASP Dependency-Check is integrated into CI/CD for vulnerability scanning.
- API documentation is generated and published as part of the build process.
- All builds are versioned and traceable.
- Docker images are built for deployment to ECS Fargate.

[KB-0910e88e-c115-4412-a137-d96b5c1a2082], [KB-0a1640fc-d3df-49c8-9862-d52514894afd]

---

## 8.2 Test Process

### 8.2.1 Test Coverage and Types

#### Unit Testing

- Minimum 80% line coverage is required for all Spring Boot services.
- All business logic, data validation, and security controls must be covered by unit tests.

#### Integration Testing

- Integration tests must pass against PostgreSQL.
- Security tests must validate authentication, authorization, and input validation.

#### System Testing

- System tests include end-to-end scenarios covering all functional requirements.
- PHI audit logging must be implemented and verified.
- API documentation must be validated against actual endpoints.

#### Performance Testing

- Performance tests must demonstrate that the system meets or exceeds legacy baseline metrics.
- Key metrics include API response time, page load time, concurrent users, and database query time.

#### Accessibility Testing

- Accessibility compliance is verified to WCAG 2.1 AA for the React UI.

#### Code and Security Review

- Code review must be completed by a senior developer.
- Security review is mandatory prior to deployment.

[KB-0a1640fc-d3df-49c8-9862-d52514894afd], [KB-0910e88e-c115-4412-a137-d96b5c1a2082]

---

### 8.2.2 Acceptance and Migration Testing

| Phase             | Test/Activity                                             | Status/Requirement                       |
|-------------------|----------------------------------------------------------|------------------------------------------|
| Parallel Run      | Both legacy and new systems audited simultaneously       | Required                                 |
| Data Integrity    | Real-time verification between legacy and new databases  | Required                                 |
| Access Control    | Parity check—no privilege escalation during migration    | Required                                 |
| Audit Trail       | Continuity—no gaps between legacy and new system logs    | Required                                 |
| Confidentiality   | Migration team signed additional confidentiality agreements | Completed                            |
| User Acceptance   | UAT for each module (see table below)                    | Required                                 |
| Rollback Plan     | Rollback plan tested and documented                      | Required                                 |

[KB-1554a441-9086-4371-85f6-cb4d7472ee1b], [KB-169a3eb6-41b7-4fce-a195-bdee1dbb2], [KB-05e90e5d-09da-4f67-85af-8f2be11cd2ce]

#### User Acceptance Testing (UAT) Phases

|   Phase | Module               | UAT Participants                     | Duration   | Status   |
|---------|----------------------|--------------------------------------|------------|----------|
| 1       | Patient Registration | Front desk staff (3), Office mgr (1) | 1 week     | Complete |
| 1       | Scheduling           | Front desk (3), Dentists (2)         | 1 week     | Complete |
| 2       | Insurance / Billing  | Billing staff (4), Office mgr (1)    | 2 weeks    | Planned  |
| 3       | Clinical Notes       | Dentists (4), Hygienists (3)         | 2 weeks    | Planned  |
| 4       | Imaging / Labs / Rx  | Dentists (4), Hygienists (3)         | 1 week     | Planned  |
| 5       | Reports / Admin      | Office mgr (2), IT (1)               | 1 week     | Planned  |

[KB-169a3eb6-41b7-4fce-a195-bdee1dbb2]

---

### 8.2.3 Performance Requirements

| Metric                       | Legacy Baseline   | Target   | Measurement Method      |
|------------------------------|-------------------|----------|------------------------|
| Patient search response time | 2.0s              | 1.0s     | End-to-end test        |
| Appointment booking latency  | 1.5s              | 1.0s     | End-to-end test        |
| API response time (p95)      | < 1,000ms         | < 500ms  | Application metrics    |
| Concurrent users             | 250               | 500+     | Load testing           |
| Database query time (avg)    | < 200ms           | < 100ms  | RDS Performance Insights|

[KB-05e90e5d-09da-4f67-85af-8f2be11cd2ce], [KB-0d9e59c7-0414-46c2-b302-2f4cbc1e9e88]

---

### 8.2.4 Security and Compliance Testing

- Authentication: OAuth 2.0 Resource Server + Azure AD
- Authorization: Method-level @PreAuthorize with SpEL
- CSRF Protection: SameSite cookies + CSRF tokens
- CORS Policy: Whitelist-based origin validation
- Content Security Policy: Strict CSP headers
- Rate Limiting: Bucket4j with Redis backend
- Input Validation: Bean Validation + custom validators
- Output Encoding: OWASP Java Encoder
- Session Management: Stateless (JWT) with Redis token blacklist
- Dependency Scanning: OWASP Dependency-Check in CI/CD

[KB-0910e88e-c115-4412-a137-d96b5c1a2082]

---

### 8.2.5 Data Migration and Integrity Verification

- Data migration is executed and verified by record count and checksum.
- Parallel run is completed for a minimum of 2 weeks; comparison reports must be clean.
- Financial and clinical data reconciliation is performed with strict tolerances (e.g., $0.01 for financial totals, 0 tolerance for record counts).
- Rollback plan is tested and documented.
- Post-migration support includes a 2-week hypercare period.

| Comparison Test                 | Tolerance   | Alert Level         |
|---------------------------------|-------------|---------------------|
| New patient registrations match | 0           | Critical            |
| Appointment count matches       | 0           | Critical            |
| Daily financial totals match    | $0.01       | Critical            |
| Claims submitted match          | 0           | High                |
| Payments posted match           | $0.01       | Critical            |
| Clinical note count matches     | 0           | High                |
| User login count comparison     | ±5%         | Low (expected diff) |

[KB-05e90e5d-09da-4f67-85af-8f2be11cd2ce], [KB-092b662f-2b03-418b-8931-ae9705639cfc]

---

### 8.2.6 Rollback and Disaster Recovery Testing

| Test Type              | Frequency     | Last Test   | Next Test   | Duration   |
|------------------------|---------------|-------------|-------------|------------|
| Backup restoration     | Monthly       | 2025-07-15  | 2025-08-15  | 2 hours    |
| Read replica promotion | Quarterly     | 2025-06-01  | 2025-09-01  | 4 hours    |
| Full DR failover       | Semi-annually | 2025-03-15  | 2025-09-15  | 8 hours    |
| DR runbook review      | Quarterly     | 2025-07-01  | 2025-10-01  | 1 hour     |

[KB-0ad2d5a6-1c32-426e-b9db-8c8bd6d32e36], [KB-0e7db777-ce75-42c0-aac9-256614f5e8a4], [KB-190fe16f-a70b-4fa5-869a-fcb047547798]

---

### 8.2.7 Compliance and Security Incident Testing

- Incident response plan is documented and tested.
- Incident response team is identified.
- Incident reporting mechanism is in place.
- Post-incident review process is established.
- Breach notification procedures are documented and tested.

[KB-052c37cd-e1b9-4e3f-8d87-e4cff20e9718], [KB-10d5f9a3-a276-4371-8028-497526cd0311]

---

## 8.3 Limitations and Gaps

- **No bulk or batch order creation:** Orders can only be created one at a time via the REST API. There is no CSV/file-based import functionality. Each order requires an individual payment and notification API call. No progress tracking or partial failure handling for batch operations exists. [KB-146a6a29-932f-485d-96d6-6a92ee610336], [KB-0a36efdc-f63e-4c6b-8191-220e34d8af3f], [KB-0a7d4d64-4d48-4214-94eb-2f3f278ec66a]
- **No parallel processing:** All cross-service calls (order → payment → notification) execute sequentially. [KB-033639ab-c6f8-4f72-a373-bf76d05dd6cf]
- **No retry/circuit breaker:** Failures in cross-service calls are logged but not retried. [KB-01305cb3-d331-4b4b-ba02-69ada467b41d]
- **No bulk notification:** Notification Service only supports single notification per API call, rate-limited to 10/sec. [KB-06c5403a-d177-4525-b247-1d7ae37a86b8]
- **No batch payment API:** Payment processing is one transaction at a time, with a maximum of 1,000,000 JPY per transaction. [KB-10744011-e9ca-48b5-ac6d-4f9f3627b7e6], [KB-186b33d7-f985-455b-8117-0cd019912510]

---

## 8.4 [GAP: Missing data for Build and Test]

If additional details on build scripts, test case examples, or CI/CD pipeline configurations are required, they are not available in the provided context.

---

**References:**  
[KB-0a1640fc-d3df-49c8-9862-d52514894afd]  
[KB-05e90e5d-09da-4f67-85af-8f2be11cd2ce]  
[KB-0910e88e-c115-4412-a137-d96b5c1a2082]  
[KB-0d9e59c7-0414-46c2-b302-2f4cbc1e9e88]  
[KB-146a6a29-932f-485d-96d6-6a92ee610336]  
[KB-033639ab-c6f8-4f72-a373-bf76d05dd6cf]  
[KB-13a05cb3-d331-4b4b-ba02-69ada467b41d]  
[KB-06c5403a-d177-4525-b247-1d7ae37a86b8]  
[KB-10744011-e9ca-48b5-ac6d-4f9f3627b7e6]  
[KB-186b33d7-f985-455b-8117-0cd019912510]  
[KB-0e7db777-ce75-42c0-aac9-256614f5e8a4]  
[KB-190fe16f-a70b-4fa5-869a-fcb047547798]  
[KB-1554a441-9086-4371-85f6-cb4d7472ee1b]  
[KB-169a3eb6-41b7-4fce-a195-bdee1dbb2]  
[KB-17a58f06-2387-412d-bf37-2f4d751e1d7e]  
[KB-0e90d327-2678-405f-b35a-294b5435dc66]  
[KB-1a54c453-d6ee-488f-bbdc-311c467a9661]  
[KB-116f84fb-2eec-4493-9762-414a92624981]  
[KB-052c37cd-e1b9-4e3f-8d87-e4cff20e9718]  
[KB-10d5f9a3-a276-4371-8028-497526cd0311]

## Contribute

# Contribute

## System Constraints and Limitations

The current system enforces several critical constraints that directly impact the ability to contribute new features or enhancements related to order management, payment processing, and notification delivery. These constraints must be considered in any contribution or system extension:

### Order Management

- **Single-Entry Only:** Orders can only be created one at a time via the REST API. There is no capability for bulk or batch order creation. Any attempt to implement bulk order import or batch processing will require significant architectural changes across multiple services.  
  *Reference:*
  - "Order creation is single-entry only. No bulk or batch order creation capability exists. Orders can only be created one at a time via the REST API." [KB-146a6a29-932f-485d-96d6-6a92ee610336]
  - "No bulk order import UI. No CSV upload, no drag-and-drop, no batch creation form." [KB-0a36efdc-f63e-4c6b-8191-220e34d8af3f]

- **No CSV/File Import:** There is no endpoint or mechanism to upload and process order data from files (CSV, Excel, etc.).  
  *Reference:*
  - "No CSV/file-based order import functionality. There is no endpoint or mechanism to upload and process order data from files (CSV, Excel, etc.)." [KB-146a6a29-932f-485d-96d6-6a92ee610336]

### Payment Processing

- **No Batch Payment API:** Payment processing is strictly one transaction at a time. There is no batch payment API, and each order requires an individual payment API call.  
  *Reference:*
  - "Payment processing handles one transaction at a time. No batch payment API exists. Each order requires an individual payment API call." [KB-0a7d4d64-4d48-4214-94eb-2f3f278ec66a]
  - "Batch payment API does not exist." [KB-10744011-e9ca-48b5-ac6d-4f9f3627b7e6]

- **Transaction Limits:** The maximum amount per transaction is 1,000,000 JPY. This limit applies to individual orders, and high-value orders exceeding this threshold will be rejected.  
  *Reference:*
  - "Amount limit of 1,000,000 JPY per single transaction." [KB-01305cb3-d331-4b4b-ba02-69ada467b41d]
  - "This limit applies to individual orders. High-value orders are rejected." [KB-10744011-e9ca-48b5-ac6d-4f9f3627b7e6]

- **No Aggregate Calculation:** It is not possible to aggregate multiple orders into a single transaction.  
  *Reference:*
  - "No aggregate amount calculation. Multiple orders cannot be combined into a single transaction." [KB-10744011-e9ca-48b5-ac6d-4f9f3627b7e6]

### Notification Service

- **No Bulk Notification:** Notifications are sent individually per order. There is no bulk notification capability; each notification requires a separate API call.  
  *Reference:*
  - "Notifications are sent individually per order. No bulk notification capability exists. Each notification requires a separate API call." [KB-0a7d4d64-4d48-4214-94eb-2f3f278ec66a]
  - "Notification service processes one notification per API call. Rate limit: 10 notifications/second." [KB-06c5403a-d177-4525-b247-1d7ae37a86b8]

- **Rate Limiting:** The notification service enforces a rate limit of 10 notifications per second. For example, sending 10,000 notifications would take at least 1,000 seconds (about 17 minutes).  
  *Reference:*
  - "Notification rate limit: 10/second. 10,000 notifications take ~17 minutes minimum." [KB-01305cb3-d331-4b4b-ba02-69ada467b41d]
  - "Notification service processes one notification per API call. Rate limit: 10 notifications/second." [KB-06c5403a-d177-4525-b247-1d7ae37a86b8]

### Batch Operations and Progress Tracking

- **No Batch Operation Tracking:** The system does not support progress tracking for multi-item operations, as batch operations do not exist.  
  *Reference:*
  - "No progress tracking for batch operations. The system has no mechanism to track progress of multi-item operations because no batch operations exist." [KB-0a7d4d64-4d48-4214-94eb-2f3f278ec66a]

- **No Partial Failure Handling:** If a batch operation is attempted (e.g., via a workaround), there is no mechanism to continue processing remaining items if one fails.  
  *Reference:*
  - "No batch error handling: If one item in a batch fails, there is no mechanism to continue processing the rest." [KB-04a84995-0820-4319-c1582821058a]

### Data Model and Schema Constraints

- **No Batch Tracking Columns:** The orders table does not include batch_id, csv_source, or bulk_import_group columns. There is no way to track which orders belong to a batch import.  
  *Reference:*
  - "orders table has no batch_id column, no csv_source field, no bulk_import_group column. There is no mechanism to track which orders belong to a batch import." [KB-0f930ddc-1f3a-4014-a015-49fe1808f8d8]

- **1:1 Payment-Order Mapping:** The payments table enforces a 1:1 unique constraint between payment and order (order_id is UNIQUE). This prevents grouping payments for batch processing.  
  *Reference:*
  - "order_id is UNIQUE — 1:1, batch grouping not possible." [KB-11739ab0-701d-4357-8083-5cc6d631106b]

### System Architecture

- **Synchronous, Sequential Processing:** All inter-service API calls are synchronous REST over HTTP. There is no message broker, event bus, or asynchronous channel. Cross-service calls (Order → Payment → Notification) are executed sequentially, not in parallel.  
  *Reference:*
  - "All inter-service communication is synchronous REST over HTTP." [KB-0d7daadd-e958-4592-900a-55db91f8aa55]
  - "Cross-service calls are sequential. Order creation flow (Order → Payment → Notification) executes sequentially. No parallel processing of payment and notification." [KB-0a7d4d64-4d48-4214-94eb-2f3f278ec66a]

- **No Retry or Circuit Breaker:** There is no retry or circuit breaker mechanism for cross-service calls. Failures are logged but not retried.  
  *Reference:*
  - "No retry or circuit breaker on any cross-service call. Failures are logged but not retried." [KB-01305cb3-d331-4b4b-ba02-69ada467b41d]

## Contribution Guidance

Given these constraints, contributions should:

- **Not attempt to implement bulk order import, batch payment, or bulk notification features** without a coordinated architectural redesign across all affected services.
- **Adhere to the single-entry, single-transaction model** for all order, payment, and notification operations.
- **Respect API rate limits and sequential processing requirements** to avoid service degradation or failures.
- **Avoid introducing batch-tracking or group-processing logic** at the data model or API level unless schema changes are approved and implemented system-wide.
- **Document any workarounds or limitations** clearly, and escalate requirements for batch or bulk operations to the architecture review board.

Any proposed enhancements or extensions must be reviewed for compliance with these foundational system constraints. Attempting to bypass or work around these limitations without architectural approval is not permitted.

*References: [KB-146a6a29-932f-485d-96d6-6a92ee610336], [KB-0a36efdc-f63e-4c6b-8191-220e34d8af3f], [KB-0a7d4d64-4d48-4214-94eb-2f3f278ec66a], [KB-10744011-e9ca-48b5-ac6d-4f9f3627b7e6], [KB-06c5403a-d177-4525-b247-1d7ae37a86b8], [KB-01305cb3-d331-4b4b-ba02-69ada467b41d], [KB-04a84995-0820-4319-c1582821058a], [KB-0f930ddc-1f3a-4014-a015-49fe1808f8d8], [KB-11739ab0-701d-4357-8083-5cc6d631106b], [KB-0d7daadd-e958-4592-900a-55db91f8aa55]