ReadTrack

The project shall include the design, development, and deployment of a cross-platform mobile application for Android and iOS. The application shall provide user authentication via social providers. The application shall provide a freemium subscription model. The application shall provide personal reading tracking and library management. The application shall provide flexible goal setting and monitoring. The application shall provide a personalized dashboard. The application shall provide daily reading tasks. The application shall provide a curated library of reading tips. The application shall provide interactive vocabulary-building games. The application shall provide AI-powered book and content recommendations. The project shall not include a web-based or desktop version of the application. The project shall not include social features such as friend lists, book clubs, or activity feeds. The project shall not include direct in-app purchasing of books. The project shall not include support for audiobooks or e-reader device integration. The project shall not include user-to-user messaging or forums.

The system shall define a 'Free User' class with access to core functionality with specified limitations. The system shall define a 'Premium User' class with unlimited access to all application features. The system shall allow Guest (Unauthenticated) users to view the login screen. The system shall prevent Guest (Unauthenticated) users from accessing application features. The system shall limit Free Users to tracking a maximum of 20 items (books/articles). The system shall limit Free Users to one active goal. The system shall limit Free Users' access to vocabulary games to a limited word list. The system shall limit Free Users to 5 AI suggestions per month. The system shall display advertisements to Free Users. The system shall provide Premium Users with unlimited tracking of books and articles. The system shall allow Premium Users to set unlimited, concurrent active goals. The system shall provide Premium Users with access to vocabulary games using an unlimited personal word list. The system shall provide Premium Users with unlimited AI suggestions. The system shall not display advertisements to Premium Users. The system shall provide Premium Users with access to advanced statistics.

The application shall support iOS version 14.0 and higher. The application shall support Android version 7.0 (Nougat) and higher. The application shall be performant on standard smartphones released within the last 4 years. The application shall require a persistent internet connection for most features, including login, data synchronization, and accessing external content.

The mobile application shall be developed using the Flutter framework (TC-001). The entire backend infrastructure shall be deployed on Amazon Web Services (AWS) (TC-002). User authentication shall be handled exclusively through third-party social providers (Google, Apple) via an Identity-as-a-Service platform (Auth0) (TC-003). The system shall not implement a native email/password authentication system (TC-003). All cloud infrastructure shall be defined and managed using the AWS Cloud Development Kit (CDK) with TypeScript (TC-004). The application shall comply with GDPR and CCPA regulations, specifically regarding the user's right to data access and erasure (RC-001).

The system shall enforce feature access controls based on the user's subscription tier (Free or Premium). <<$Addition>> Justification: Addresses GAP-003. This section makes the Freemium business model, a core strategic decision, actionable by defining the specific rules and system behaviors required for implementation. Given a Free User attempts to add the 21st book to their library, the system shall prevent the action. Given a Free User attempts to add the 21st book to their library, the system shall display a prompt to upgrade. Given a Free User has one active goal, the option to create another goal shall be disabled or lead to an upgrade prompt. Given a Free User has received 5 AI suggestions in the current month, any action to request another suggestion shall be blocked. Given a Free User has received 5 AI suggestions in the current month, the system shall present an upgrade prompt. For a Premium User, all feature limits shall be removed. The system shall allow users to view their subscription status and upgrade their plan. The app shall contain a clearly accessible screen showing the user's current tier (Free/Premium). This screen shall present the benefits of the Premium Tier and provide a button to initiate the upgrade process. Tapping the upgrade button shall invoke the native in-app purchase flow for the Apple App Store or Google Play Store. The backend shall listen for server-to-server webhooks from Apple/Google to reliably update the user's subscription status.

The system shall present a guided, multi-step onboarding flow to users upon their first login. <<$Addition>> Justification: Addresses GAP-001. A guided onboarding is critical for user activation and retention, preventing churn by ensuring users understand the app's core value proposition from the first session. The onboarding flow shall prompt the user to set their first yearly reading goal. The onboarding flow shall guide the user to search for and add their 'Currently Reading' book to their library. The onboarding flow shall include a brief, dismissible tour highlighting the Dashboard, the button to log a reading session, and the Goals tab. Upon completion of the onboarding flow, the user shall be directed to the main Dashboard.

User registration and login shall be handled exclusively via third-party social providers. <<$Resolution>> Justification: Resolves CONT-001 by clarifying the ambiguous 'Secure registration' requirement with a specific, actionable implementation strategy. The login screen shall present 'Sign in with Google' and 'Sign in with Apple' options. Selecting a sign-in option shall initiate the platform-native OAuth 2.0/OIDC flow. Upon successful authentication, the system shall create a new user account for a first-time user or log in an existing user. The backend shall securely validate the token from the provider and issue its own JWT for session management. Users shall be able to change their display name. Users shall be able to change their profile picture. Users shall be able to granularly control which push notifications they receive. <<$Addition>> Justification: Addresses GAP-006 by providing users with essential control over application communications. A settings screen shall provide separate toggles to enable/disable 'Goal Reminders' and 'Daily Task Reminders' notifications. Users shall have a clear and accessible option to permanently delete their account and all associated data. <<$Addition>> Justification: Addresses GAP-002 by adding a feature that is legally required for GDPR/CCPA compliance. An option for account deletion shall be present within the app's account settings. Initiating deletion shall present a confirmation dialog explaining that the action is irreversible. Upon confirmation, the backend shall trigger a process to perform a hard delete of all PII and user-generated content. Users shall be able to request and download an export of their personal reading data. <<$Addition>> Justification: Addresses GAP-002, fulfilling the 'Right to Data Portability' requirement of GDPR. An option to 'Export My Data' shall be available in the account settings. Triggering the export shall queue an asynchronous job on the backend. Upon completion, the user shall be notified with a secure, time-limited link to download their data. The exported file shall be in a machine-readable format (CSV or JSON) and contain their library list and reading session history.

Users shall be able to manage a personal library of books and articles organized into distinct virtual shelves. <<$Addition>> Justification: Addresses GAP-004. This significantly expands the original requirement from a simple tracker into a comprehensive library management system. The library shall be organized into four shelves: 'Currently Reading,' 'Want to Read,' 'Read,' and 'Did Not Finish (DNF).' Users shall be able to move an item between shelves. Moving an item to 'Read' or 'DNF' shall prompt for a completion date. To add a book, the user shall be able to search by Title, Author, or ISBN. The search shall query an external book data API. To add an article, the user shall be able to paste a URL and provide a custom title. Users shall be able to record reading sessions for items in their 'Currently Reading' shelf. Users shall be able to log progress by entering the page number they have read up to. Users shall be able to use a start/stop timer or manually enter the time spent reading for a session. The system shall calculate and store the pages read and minutes spent for the session. Users shall be able to view, edit, and delete past reading sessions. For any book, the user shall be able to view a history of all logged reading sessions. A search bar shall allow users to find items in their library by title or author. Filter options shall be available to view items by their shelf status. The app shall display statistics such as total pages read, total time spent, and total books completed. The app shall calculate and display the user's average reading speed (pages per hour).

Users shall be able to set various types of reading goals. <<$Addition>> Justification: Addresses GAP-005. The original 'yearly goal' was too rigid. Adding flexible goal types and a defined lifecycle makes the feature more personalized and effective for habit formation. When creating a goal, users shall be able to choose from types: Number of books per year, Number of pages per day/week/month, and Amount of time (minutes) per day/week/month. Users shall be able to set a target value for their chosen goal type. The UI shall display progress bars, percentage completion, or other visual cues against all active goals. Progress shall update automatically after each reading session is logged. At the end of a goal's period, the app shall present a 'Year in Review' summary of achievements. Following the summary, the app shall prompt the user to set a new goal for the upcoming period.

The dashboard shall display the book(s) on the 'Currently Reading' shelf. The dashboard shall show a summary of progress toward all active goals. The dashboard shall provide a prominent shortcut to log a new reading session.

Users shall be able to create custom daily tasks (e.g., 'Read one chapter'). The app shall suggest daily tasks based on the user's active goals. <<$Addition>> Users shall be able to mark tasks as complete.

The system shall provide a library of articles offering reading strategies and study techniques, with content fetched from a Headless CMS. <<$Resolution>> Justification: Resolves CONT-003 by defining the technical implementation for content management, allowing for dynamic updates without app releases. The app shall have a dedicated section for 'Tips'. Content for the tips shall be fetched via an API call to a Headless CMS. The app shall cache the content to reduce load times and support offline viewing of previously loaded tips.

The app shall include at least two game types (e.g., Flashcards, Multiple-Choice Quiz). Games shall be populated from the user's personal vocabulary list. Users shall be able to manually add words to a personal vocabulary list that populates the games. <<$Addition>> Justification: Addresses GAP-006 and CONT-003. It clarifies the crucial missing detail of how words get into the game and formalizes the content management strategy. The app shall provide a feature for users to manually enter a word, its definition, and an example sentence. Pre-populated word lists for Free Tier users or game templates shall be managed in and fetched from a Headless CMS. <<$Resolution>>

The app shall provide intelligent book recommendations by sending user data as prompts to a third-party LLM API. <<$Resolution>> Justification: Resolves CONT-002 by specifying the use of an LLM API. The backend shall have a service that constructs a detailed prompt based on user data. The service shall securely call an external LLM API with the prompt. The service shall parse the LLM's response and format it as a user-facing recommendation. The recommendation process shall be asynchronous to avoid blocking the user interface. The prompt sent to the LLM shall include data points such as the user's reading history, stated goals, and words added to their vocabulary list. Users shall be able to provide feedback on suggestions to improve future recommendations. <<$Addition>> Justification: Addresses GAP-006 by adding a feedback loop, which is essential for any high-quality recommendation system. Each recommendation shall have interactive elements allowing the user to dismiss it or save it. This feedback shall be stored and included in future prompts to the LLM to refine its output.

The UI shall be modern, clean, and visually engaging ('catchy'). The UI shall use a consistent color palette and typography suitable for the target demographic (Students age group 17-28). The UI shall adapt gracefully to various screen sizes and densities across supported iOS and Android devices. The application shall strive to meet Web Content Accessibility Guidelines (WCAG) 2.1 Level AA standards.

The app shall integrate with the native SDKs for Google Sign-In and Sign in with Apple (SI-001). The backend shall integrate with Auth0 for managing the OIDC/OAuth2 protocol and issuing JWTs (SI-002). The backend shall make secure REST API calls to a third-party Large Language Model provider (SI-003). The client application and/or backend shall fetch content via a REST or GraphQL API from a Headless CMS provider (SI-004). The backend shall integrate with an external book database API to fetch book metadata (SI-005). The backend shall receive and process server-to-server notifications (webhooks) from the Apple App Store and Google Play Billing for subscription lifecycle events (SI-006).

All communication between the mobile client and the backend API shall use HTTPS over TCP/IP. The API shall use JSON for all request and response bodies. Communication shall be secured using TLS 1.2 or higher. Client requests to protected endpoints shall include a JWT in the `Authorization: Bearer <token>` header.

P95 latency for all core API endpoints shall be less than 200ms (NFR-PERF-001). The mobile application's main Dashboard screen shall load and become interactive in under 1.5 seconds on a standard 4G network connection (NFR-PERF-002). Asynchronous operations shall not block the UI and shall provide feedback to the user that a process is underway (NFR-PERF-003).

The primary database shall be configured with automated, continuous backups and Point-In-Time Recovery (PITR) enabled for a recovery window of at least 14 days (NFR-REL-001). The system architecture shall leverage highly available managed AWS services to minimize single points of failure (NFR-REL-002).

All user authentication shall be delegated to secure third-party providers (Google, Apple) via Auth0 (NFR-SEC-001). The system shall not store passwords or other sensitive credentials (NFR-SEC-001). The system shall implement Role-Based Access Control (RBAC) (NFR-SEC-002). A user's role (`free_user`, `premium_user`) shall be encoded in their JWT and used by the API Gateway and backend services to enforce feature access (NFR-SEC-002). All user data stored in the primary database (Aurora) and file storage (S3) shall be encrypted at rest using AWS KMS (NFR-SEC-003). All data transmitted between the client and server, and between internal services, shall be encrypted using TLS 1.2+ (NFR-SEC-004). All third-party API keys shall be stored securely in a secret management service and never exposed on the client side (NFR-SEC-005).

The backend services shall have a target uptime of 99.9%, excluding planned maintenance (NFR-A-001). Planned maintenance windows shall be scheduled during periods of low user activity (NFR-A-002).

The backend architecture shall be able to scale horizontally to support an initial target of 10,000 concurrent users (NFR-S-001). The database solution shall support read-heavy workloads through the use of read replicas and scale write capacity automatically (NFR-S-002). Stateless services shall scale automatically based on request volume (NFR-S-003).

The backend shall be designed as a set of loosely coupled microservices (NFR-M-001). All infrastructure shall be managed via Infrastructure as Code (AWS CDK) for repeatability and version control (NFR-M-002). The codebase shall adhere to defined linting rules, and all new code shall be accompanied by unit and integration tests, with a target of 80% minimum code coverage (NFR-M-003).

The Cloud Provider shall be Amazon Web Services (AWS). <<$Change>> The Mobile Framework shall be Flutter 3.x. <<$Change>> The Backend Language/Framework shall be Node.js (v18+) with TypeScript and Fastify. <<$Change>> The Primary Database shall be Amazon Aurora (PostgreSQL compatible) Serverless v2. <<$Change>> The Caching solution shall be Amazon ElastiCache for Redis. <<$Change>> The File Storage solution shall be Amazon S3. <<$Change>> The Container Orchestration solution shall be AWS Fargate. <<$Change>> The Serverless Compute solution shall be AWS Lambda. <<$Change>> The API Gateway shall be Amazon API Gateway. <<$Change>> The Message Queue shall be Amazon SQS. <<$Change>> The Identity Provider shall be Auth0. <<$Change>> The CI/CD solution shall be GitHub Actions. <<$Change>> The Infrastructure as Code tool shall be AWS CDK with TypeScript. <<$Change>> The Monitoring solution shall be AWS CloudWatch and AWS X-Ray. <<$Change>>

Business-level dashboards shall be created to track key metrics such as Daily Active Users (DAU), Monthly Active Users (MAU), subscription conversion rates, and feature engagement. Key performance indicators for all backend services shall be collected using Amazon CloudWatch Metrics. All services and functions shall output structured JSON logs to Amazon CloudWatch Logs for centralized aggregation, searching, and analysis. AWS X-Ray shall be enabled to trace requests as they travel through the distributed system. CloudWatch Alarms shall be configured to automatically notify the development team of critical issues. Alerts shall be triggered if API 5xx error rates exceed 1%. Alerts shall be triggered if P99 latency surpasses 1 second. Alerts shall be triggered for critical failures in asynchronous jobs.

The ReadTrack application is envisioned as a dedicated mobile platform for students aged 17-28, designed to foster better reading habits and support academic growth. The core objective is to enable users to effectively track their personal reading progress and set achievable yearly reading goals. **Key Functional Areas include:** * **User Management:** Secure registration, login, and profile management to personalize the user experience. * **Reading Tracking:** Comprehensive tools to add and manage books/articles, record reading sessions, and visualize progress through detailed statistics (pages read, time spent, books completed). * **Goal Management:** Functionality for users to set and monitor yearly reading goals, supported by visual progress indicators and optional reminders to maintain motivation. * **Dashboard:** A personalized central hub providing a quick overview of current reading activities, goal progress, and access to key features. * **Daily Tasks:** A system for users to create, track, and complete daily reading-related tasks, aiding in habit formation. * **Tips:** A curated library of educational content offering reading strategies, study techniques, and productivity hacks relevant to students. * **Vocabulary Games:** Interactive and engaging games designed to help users learn and retain new words from their reading, complete with personal word lists and progress tracking. * **AI Suggestions:** Intelligent recommendations for books, articles, study strategies, and goal adjustments, personalized based on user data and preferences. **Non-Functional Requirements emphasize:** * **Usability:** A highly user-friendly interface with intuitive navigation and a visually appealing, "catchy UI and colours" tailored for the target demographic, including basic accessibility considerations. * **Compatibility:** Full support for both Android and iOS platforms, ensuring broad accessibility across various devices and recent operating system versions. * **Performance:** The app will be responsive and efficient, ensuring quick loading times and minimal resource consumption. * **Security:** Robust measures for data privacy and secure user authentication to protect personal reading habits and account information. * **Scalability:** The architecture will be designed to support a growing user base and increasing data volumes without performance degradation. * **Maintainability:** A well-structured and documented codebase to facilitate future updates and extensions. All identified requirements are technically feasible. The detailed specification elaborates on the initial high-level requests, making implicit functionalities explicit and adding necessary detail to ensure a comprehensive and robust application design.

## 1. Introduction The ReadTrack application aims to provide students aged 17-28 with a comprehensive and engaging platform to track their personal reading habits, set yearly reading goals, and enhance their vocabulary and study techniques. The app will offer a personalized experience through a dashboard, daily tasks, educational tips, interactive vocabulary games, and AI-driven suggestions, all within a catchy and user-friendly interface on both Android and iOS devices. ## 2. Functional Requirements ### 2.1 User Management * <<$Addition>>**User Registration and Login:** Secure creation and authentication of user accounts, supporting email/password and potentially social logins.<<$Addition>> * <<$Addition>>**User Profile Management:** Ability for users to view and edit their personal details, reading preferences (genres, formats), and academic level.<<$Addition>> * **Enhancement Justification:** These additions are fundamental for any personalized application, enabling individual tracking and goal setting, and are implicitly required for "personal reading habits." ### 2.2 Reading Tracking * <<$Addition>>**Book/Article Management:** Users can add, edit, and categorize books, articles, or other reading materials they are currently reading, have read, or plan to read. This includes details like title, author, genre, total pages/words, and publication date.<<$Addition>> * <<$Addition>>**Progress Tracking:** Users can record reading sessions by specifying start/end times, pages read, or duration. The app will automatically calculate progress for each reading item.<<$Addition>> * <<$Addition>>**Reading Statistics:** Display comprehensive metrics such as total pages read, total reading time, number of books/articles completed, average reading speed, and reading streaks.<<$Addition>> * **Enhancement Justification:** These elaborations define the core mechanics of "track personal reading habits" and are essential for a robust tracking system. ### 2.3 Goal Management * **Set yearly goals:** Users can define and customize yearly reading goals (e.g., number of books to read, total pages, specific genres to explore, or daily reading time targets). * <<$Addition>>**Goal Progress Visualization:** Provide clear visual representations (e.g., progress bars, charts) of the user's advancement towards their yearly goals.<<$Addition>> * <<$Addition>>**Goal Reminders/Notifications:** Optional push notifications to remind users about their goals and encourage consistent reading.<<$Addition>> * **Enhancement Justification:** These additions enhance the "set yearly goals" requirement by providing feedback and motivational tools. ### 2.4 Dashboard * **Dashboard:** A centralized, personalized view providing an overview of key information. * <<$Addition>>**Personalized Summary:** Display current reading progress, upcoming daily tasks, real-time goal progress, recent achievements, and quick insights.<<$Addition>> * <<$Addition>>**Quick Access:** Provide shortcuts to frequently used features such as "Start Reading Session," "Add New Book," or "Review Vocabulary."<<$Addition>> * **Enhancement Justification:** These additions clarify the content and utility of the "Dashboard" feature, ensuring it is user-friendly and informative. ### 2.5 Daily Tasks * **Daily Tasks:** A feature to help users manage and adhere to their daily reading-related activities. * <<$Addition>>**Task Creation & Customization:** Users can create, edit, and schedule custom daily reading tasks (e.g., "Read 30 pages of 'Book X'," "Review 10 vocabulary words," "Complete a chapter").<<$Addition>> * <<$Addition>>**Task Tracking & Completion:** Users can mark tasks as complete, and the app will track daily/weekly task completion rates and streaks.<<$Addition>> * **Enhancement Justification:** These additions elaborate on the "Daily Tasks" requirement, making it a functional and actionable feature for habit formation. ### 2.6 Tips * **Tips:** A section dedicated to providing useful advice and educational content. * <<$Addition>>**Curated Content Library:** Offer a library of reading tips, effective study techniques, productivity hacks, and general educational content relevant to students.<<$Addition>> * <<$Addition>>**Categorization & Search:** Tips should be categorized (e.g., "Speed Reading," "Note-Taking," "Focus") and searchable for easy access.<<$Addition>> * **Enhancement Justification:** These additions define the scope and usability of the "Tips" feature, ensuring it provides value to the target audience. ### 2.7 Vocab Games * **Vocab games:** Interactive and engaging games designed to help users learn and retain new vocabulary. * <<$Addition>>**Word List Management:** Users can add words encountered during their reading to a personal vocabulary list, including definitions, example sentences, and context.<<$Addition>> * <<$Addition>>**Multiple Game Modes:** Implement various engaging game modes such as flashcards, matching games, fill-in-the-blanks, and spelling challenges.<<$Addition>> * <<$Addition>>**Progress Tracking:** Monitor vocabulary learning progress, track mastery levels for individual words, and suggest words for review.<<$Addition>> * **Enhancement Justification:** These additions detail the functionality of "Vocab games," making it a comprehensive and effective learning tool. ### 2.8 AI Suggestions * **AI suggestions:** Intelligent recommendations to enhance the user's reading and learning experience. * <<$Addition>>**Personalized Reading Recommendations:** Suggest books, articles, or genres based on the user's reading history, stated preferences, and current goals.<<$Addition>> * <<$Addition>>**Study Strategy Suggestions:** Offer AI-driven advice on optimizing reading habits, improving comprehension, or adjusting study schedules based on user patterns.<<$Addition>> * <<$Addition>>**Goal Adjustment Recommendations:** Suggest adjustments to reading goals based on historical performance, current reading pace, and identified patterns.<<$Addition>> * **Enhancement Justification:** These additions clarify the types of "AI suggestions" that will be provided, leveraging AI for a more personalized and effective user experience. ## 3. Non-Functional Requirements ### 3.1 Performance * <<$Addition>>**Responsiveness:** The application should load quickly (e.g., within 3 seconds on a stable network) and respond to user interactions without noticeable delay.<<$Addition>> * <<$Addition>>**Efficiency:** The app should efficiently utilize device resources, minimizing battery consumption and data usage.<<$Addition>> * **Enhancement Justification:** Standard quality attributes for any mobile application, ensuring a smooth user experience. ### 3.2 Security * <<$Addition>>**Data Privacy:** All user data, including reading habits, personal information, and vocabulary lists, must be securely stored (encrypted at rest and in transit) and handled in compliance with relevant data protection regulations.<<$Addition>> * <<$Addition>>**Authentication Security:** Robust authentication mechanisms (e.g., strong password policies, multi-factor authentication options) to protect user accounts from unauthorized access.<<$Addition>> * **Enhancement Justification:** Critical for any application handling personal user data, ensuring trust and compliance. ### 3.3 Usability * **User friendly:** The application must have an intuitive navigation structure, clear interface elements, and an easy-to-understand workflow. * **Catchy UI and colours:** The user interface should be visually appealing, modern, and utilize a vibrant color palette suitable for the target student demographic. * <<$Addition>>**Accessibility:** Adherence to basic accessibility standards (e.g., sufficient color contrast, scalable text, screen reader compatibility) to ensure usability for a wider audience.<<$Addition>> * **Enhancement Justification:** Expands on the user's request for a user-friendly and catchy UI by including accessibility as a key aspect of usability. ### 3.4 Compatibility * **Android and iOS support:** The application must be fully functional and available on both major mobile operating systems. * <<$Addition>>**Device Compatibility:** Support for a wide range of Android and iOS devices, targeting the last 3 major operating system versions for each platform.<<$Addition>> * **Enhancement Justification:** Clarifies the scope of platform and device support for the application. ### 3.5 Scalability * <<$Addition>>**User Base:** The system architecture should be designed to support a growing number of concurrent users (e.g., tens of thousands to hundreds of thousands) without significant degradation in performance.<<$Addition>> * <<$Addition>>**Data Volume:** The backend infrastructure must be capable of handling increasing amounts of user reading data, vocabulary lists, and content for tips and suggestions.<<$Addition>> * **Enhancement Justification:** Important for the long-term success and growth of the application, ensuring it can accommodate future demand. ### 3.6 Maintainability * <<$Addition>>**Code Quality:** The codebase should be well-structured, modular, documented, and adhere to coding best practices to facilitate easy maintenance, debugging, and future feature extensions.<<$Addition>> * <<$Addition>>**Updatability:** The application architecture should allow for easy deployment of updates, bug fixes, and new features without significant downtime or disruption to users.<<$Addition>> * **Enhancement Justification:** Ensures the application can evolve and be supported effectively over its lifecycle. ## 4. Target Audience * **Students age group 17-28:** All features, content, UI/UX design, and communication within the app should be tailored to resonate with this specific demographic, focusing on their academic needs, learning styles, and digital engagement preferences. **Enhancement Justification:** No infeasible requirements were identified based on the provided criteria. All original statements appear to be technically, logically, and practically feasible. The additions marked with `<<$Addition>>` serve to elaborate on the high-level requirements, making implicit requirements explicit and adding necessary detail for a comprehensive specification. These elaborations clarify the scope and functionality without altering the original functional intent, aligning with the understanding that "some may require further clarification during the detailed design phase."