Day 4 Data Structure Codex AI Architect

Data design tasks based on Codex Client Workspace

Differences in data structure understanding, terminology fragmentation, and change impact propagation issues that startups face during the MVP development stage
This is a practical AI collaboration task board that automatically analyzes and resolves using Codex.

Day 4 Startup MVP Tasks

From aligning data structures to standardizing terminology and sharing the impact of changes — experience core workflows with Codex as your data design partner.

TASK 1
Task 1

Task 1. API contract creation practice

Task 01: Automatic creation of API Contract based on planning requirements and screen design

By deriving key entities and relationships (Mermaid ERD) from planning meeting minutes written in natural language, the gap in data model understanding between planners and developers is resolved with AI.

target numberDeriving RESTful API contract specifications
core toolsCodex Client Workspace
scope of practiceData Structure Alignment
Step 1 📂 Prepare meeting minutes file (day4_meeting_notes.md) and upload Codex
Step 2 🔍 Request Codex to derive API list and define Req/Res variable names
ERD Req/Res Design RESTful
expected output erd-schema.md (Data Specification and ERD)
Task 1 Entry to the lab
TASK 2
Task 2

Task 2. API mismatch detection practice

Task 02: Detect inconsistencies by comparing planning documents and API specifications

Create a review report by cross-checking requirements definitions, screen definitions, and API specification drafts to find API endpoints and fields that are missing or inconsistent with planning requirements or screen UI design.

target numberCompletion of API consistency review report
core toolsCodex Client Workspace
scope of practiceSpec Auditing Standardization
Step 1 📁 Preparation of two planning documents and API specification draft
Step 2 📋 Request for consistency review of inconsistencies and missing functions between documents with Codex
Consistency Check Spec Auditing Validation
expected output project-glossary.md (Standard Glossary)
Task 2 Entry to the lab
TASK 3
Task 3

Task 3. API change impact analysis practice

Task 03: Analysis of functions, documents, and interfaces affected by API changes

When API parameters or status change according to changes in business specifications, a list of DB schemas, front-end UI screens, and API specifications that require serial modification is created as an impact analysis report.

target numberCompletion of API change impact analysis
core toolsCodex Client Workspace
scope of practiceChange Impact Analysis
Step 1 📂 Prepare API change request file
Step 2 🔄 Request analysis of UI and DB spec chain impact scope with Codex
Change Management Impact Analysis UI/API Sync
expected output change-impact-report.md (Change Impact Analysis)
Task 3 Entry to the lab
🚀 In-depth Mission — Data Design Master Course
MISSION 1
Mission 1

Mission 1. API review and improvement practice

Mission 01: Review and suggest improvement of API quality using Codex

We review the quality of existing API designs and come up with improvements based on REST API design standards (noun-type URL, use of appropriate methods) and consistent error handling specifications (RFC standard error schema).

target numberAPI review report completed
core toolsCodex Client Workspace
scope of practiceDesign API Review & Error Schema
Step 1 📂 Prepare API specifications and review meeting conversation transcripts
Step 2 🔍 Request Codex to review compliance with REST standards and propose standard error specifications
API Review RESTful Standards Error Schema
expected output design-decision-log.md (Decision record document)
Mission 1 Lab Entry
MISSION 2
Mission 2

Mission 2. API test scenario creation practice

Mission 02: Automatically create API test scenarios including normal and exception situations

Based on the completed API contract, we create test cases that verify not only the normal operation flow (Happy Path) but also various exception situations (Sad Path) such as missing essential keys, format errors, exceeding limits, and expiration of permissions.

target numberComplete API test scenario
core toolsCodex Client Workspace
scope of practiceEdge Case Discovery & Integrity Guard
Step 1 📂 Preparation of API contract specifications
Step 2 🛡️ Derive all normal/exceptional cases and create test scenarios with Codex
Test Scenarios Happy/Sad Path Quality Guard
expected output edge-case-analysis.md (Exception scenario report)
Mission 2 Lab Entry