←Back to Docs
Core Docs
Home
Documentation / Case Study

QUAD Case Study: Calculator Web Application

Agile vs QUAD - Side-by-Side Comparison

This case study demonstrates how a simple Calculator Web Application would be built using traditional Agile/Scrum vs QUAD methodology. It illustrates where human gates exist and where AI agents can run autonomously.

The Project: Calculator Web App

Scope: Build a web-based calculator with basic operations (+, -, *, /) Features:
  • • Basic arithmetic operations
  • • Clear and backspace functionality
  • • Keyboard support
  • • Responsive design
  • • Unit tests

    • Visual Comparison: Process Flow

    +===========================================================================+
AGILE/SCRUM APPROACH (Traditional)
+===========================================================================+

[Human]         [Human]         [Human]         [Human]

v               v               v               v

    
PlanningDevTestingReview
4hrs9days1day2hrs
    

v               v               v               v
[Meeting]       [Coding]        [Manual]        [Demo]
[Standup]       [Reviews]       [QA Test]       [Retro]
[Grooming]      [Meetings]      [Bug Fix]       [Meet]

Human Effort: ~80%Meeting Time: ~20%Duration: 2 weeks

+===========================================================================+

    
+===========================================================================+
QUAD APPROACH (AI-Augmented)
+===========================================================================+

[Human]                                                    [Human]

v                                                          v
    
RequireStoryDevTestDeployCheck
1hrAUTOAUTOAUTOAUTO30m
^

[Human                                                   [Human
Approval]                                               Approval]

Human Effort: ~20%Meeting Time: ~5%Duration: 2-3 days

+===========================================================================+

    Detailed Phase Comparison

    Phase 1: Requirements & Planning

    +---------------------------+------------------------------------------+
AGILE/SCRUMQUAD
+---------------------------+------------------------------------------+

[HUMAN] Product Owner[HUMAN] BA writes brief:
writes user stories"Calculator with +,-,*,/ operations"
- 2-4 hours- 15 minutes

[HUMAN] Sprint Planning[AGENT] Story Agent expands:
- Team estimates- Generates detailed stories
- 4 hours meeting- Creates acceptance criteria
- Adds edge cases
[HUMAN] Grooming- Estimates complexity
- Clarify stories- AUTO: 5 minutes
- 2 hours meeting
[HUMAN GATE] Review & Approve
Total: ~8 hours- BA reviews generated stories
- 30 minutes

Total: ~50 minutes
+---------------------------+------------------------------------------+

    Phase 2: Development

    +---------------------------+------------------------------------------+
AGILE/SCRUMQUAD
+---------------------------+------------------------------------------+

[HUMAN] Daily Standup[AGENT] Dev Agent (UI):
- 15 min x 10 days- Scaffolds React component
- 2.5 hours total- Creates calculator layout
- Implements button handlers
[HUMAN] Developer codes- AUTO: 10 minutes
- 8+ hours/day
- Manual setup[AGENT] Dev Agent (API):
- Manual testing- Creates calculation service
- Adds validation logic
[HUMAN] Code Review- AUTO: 5 minutes
- 1-2 hours per PR
- Back and forth[AGENT] Code Review Agent:
- Pre-reviews for patterns
[HUMAN] Fix review- Checks security
comments- Suggests improvements
- Variable time- AUTO: 2 minutes

Total: ~40-60 hours[HUMAN GATE] Developer Review
- Reviews AI-generated code
- Makes adjustments
- 2-3 hours

Total: ~3 hours human + 17 min AI
+---------------------------+------------------------------------------+

    Phase 3: Testing

    +---------------------------+------------------------------------------+
AGILE/SCRUMQUAD
+---------------------------+------------------------------------------+

[HUMAN] QA writes test[AGENT] Test Generator Agent:
cases- Reads flow documentation
- 4-8 hours- Generates unit tests
- Creates integration tests
[HUMAN] Manual testing- AUTO: 5 minutes
- Click through UI
- 2-4 hours[AGENT] UI Test Agent:
- Runs Playwright automation
[HUMAN] Bug reporting- Screenshots all screens
- Document issues- AUTO: 3 minutes
- 1-2 hours
[AGENT] API Test Agent:
[HUMAN] Bug fixing- Tests calculation logic
- Back to dev- Edge case validation
- Variable time- AUTO: 1 minute

Total: ~10-20 hours[HUMAN GATE] QA Review
- Reviews test results
- Exploratory testing
- 1 hour

Total: ~1 hour human + 9 min AI
+---------------------------+------------------------------------------+

    Phase 4: Deployment & Review

    +---------------------------+------------------------------------------+
AGILE/SCRUMQUAD
+---------------------------+------------------------------------------+

[HUMAN] DevOps deploys[AGENT] Deploy Agent (DEV):
- Manual pipeline- Builds and deploys to DEV
- 1-2 hours- AUTO: 2 minutes

[HUMAN] Sprint Review[AGENT] Deploy Agent (QA):
- Demo to stakeholders- After tests pass
- 2 hours meeting- Deploys to QA environment
- AUTO: 2 minutes
[HUMAN] Retrospective
- What went well/wrong[HUMAN GATE] Checkpoint
- 1-2 hours meeting- Demo to stakeholders
- 30 minutes
[HUMAN] Production
deploy[HUMAN GATE] Production Approval
- Manual approval- Final sign-off
- 1 hour- 15 minutes

Total: ~6-8 hours[AGENT] Deploy Agent (PROD):
- After approval
- Deploys to production
- AUTO: 2 minutes

Total: ~45 min human + 6 min AI
+---------------------------+------------------------------------------+

    Summary Comparison

    MetricAgile/ScrumQUADImprovement Total Human Hours64-88 hours5-6 hours92% reduction Meeting Time12-16 hours1.5 hours90% reduction Duration2 weeks2-3 days85% faster Human GatesEvery step4 checkpointsFocused review AI AutomationNone~90% of tasksMaximum leverage

    Human Gates in QUAD

    These are the non-negotiable human approval points:

    +-----------------------------------------------------------------------+
QUAD HUMAN GATES
+-----------------------------------------------------------------------+

GATE 1: Requirements Approval
WHO:  Business Analyst / Product Owner
WHEN: After Story Agent generates detailed stories
WHAT: Review acceptance criteria, edge cases, estimates
TIME: 30 minutes

GATE 2: Code Review
WHO:  Developer / Tech Lead
WHEN: After Dev Agent generates code
WHAT: Review logic, patterns, security, quality
TIME: 2-3 hours

GATE 3: QA Sign-off
WHO:  QA Engineer
WHEN: After Test Agents complete automation
WHAT: Review results, exploratory testing, edge cases
TIME: 1 hour

GATE 4: Production Approval
WHO:  Tech Lead / Director
WHEN: Before Deploy Agent pushes to production
WHAT: Final sign-off, risk assessment, rollback plan
TIME: 15-30 minutes

+-----------------------------------------------------------------------+

    AI Agent Autonomous Zones

    These tasks run without human intervention:

    +-----------------------------------------------------------------------+
QUAD AI AUTONOMOUS ZONES
+-----------------------------------------------------------------------+

ZONE 1: Story Expansion
AGENT: Story Agent
INPUT: Brief requirement from BA
OUTPUT: Detailed user stories with acceptance criteria
AUTO: Yes - runs immediately on input

ZONE 2: Code Generation
AGENT: Dev Agent (UI + API)
INPUT: Approved user stories
OUTPUT: Scaffolded code, components, services
AUTO: Yes - triggers on story approval

ZONE 3: Test Generation & Execution
AGENT: Test Generator + UI Test + API Test Agents
INPUT: Code and flow documentation
OUTPUT: Test cases, execution results, coverage report
AUTO: Yes - triggers on code push

ZONE 4: DEV/QA Deployment
AGENT: Deploy Agent
INPUT: Code merge + tests passing
OUTPUT: Deployed to DEV/QA environment
AUTO: Yes - triggers on merge (PROD needs approval)

ZONE 5: Documentation Generation
AGENT: Documentation Agent
INPUT: Code changes, API endpoints
OUTPUT: Updated flow docs, API docs, changelog
AUTO: Yes - triggers on deployment

+-----------------------------------------------------------------------+

    Flow Document Example: Calculator Add Operation

    This is what a QUAD Flow Document looks like for a single feature:

    <h1 class="text-3xl font-bold text-white mb-8">FLOW: Calculator - Addition Operation</h1>

    <h2 class="text-2xl font-bold text-blue-300 mt-10 mb-6">Overview</h2>
FieldValue
    
Flow IDFLOW_CALC_ADD_001
OwnerCircle 1 (BA)
StatusActive

    

    <h2 class="text-2xl font-bold text-blue-300 mt-10 mb-6">Step 1: User Enters First Number</h2>
    

    <h3 class="text-xl font-bold text-white mt-8 mb-4">UI</h3>
ElementTypeValidation
    
DisplayTextFieldNumbers only, 12 max
Number ButtonsButton0-9, enabled

    <h3 class="text-xl font-bold text-white mt-8 mb-4">Screenshot</h3>
[Calculator with "5" displayed]
    

    <h3 class="text-xl font-bold text-white mt-8 mb-4">API</h3>
None (client-side only)
    

    <h3 class="text-xl font-bold text-white mt-8 mb-4">Database</h3>
None
    

    <h3 class="text-xl font-bold text-white mt-8 mb-4">Test Cases</h3>
TC IDScenarioInputExpected
    
TC001Single digit5Display: "5"
TC002Multiple digits123Display: "123"
TC003Leading zero0, 5Display: "5"

    

    <h2 class="text-2xl font-bold text-blue-300 mt-10 mb-6">Step 2: User Clicks Addition</h2>
    

    <h3 class="text-xl font-bold text-white mt-8 mb-4">UI</h3>
ElementTypeValidation
    
+ ButtonButtonEnabled when display has value
DisplayTextFieldShows first number

    <h3 class="text-xl font-bold text-white mt-8 mb-4">Test Cases</h3>
TC IDScenarioInputExpected
    
TC004Click ++Stores first number
TC005Click + (empty)+No action

    

    <h2 class="text-2xl font-bold text-blue-300 mt-10 mb-6">Step 3: User Enters Second Number</h2>
    

    <h3 class="text-xl font-bold text-white mt-8 mb-4">UI</h3>
Same as Step 1
    

    <h3 class="text-xl font-bold text-white mt-8 mb-4">Test Cases</h3>
TC IDScenarioInputExpected
    
TC006Enter second3Display: "3"

    

    <h2 class="text-2xl font-bold text-blue-300 mt-10 mb-6">Step 4: User Clicks Equals</h2>
    

    <h3 class="text-xl font-bold text-white mt-8 mb-4">UI</h3>
ElementTypeValidation
    
= ButtonButtonEnabled when operation pending
DisplayTextFieldShows result

    <h3 class="text-xl font-bold text-white mt-8 mb-4">API (if using server-side calculation)</h3>
    POST /api/calculate Content-Type: application/json

    Request: { "operand1": 5, "operand2": 3, "operation": "add" }

    Response (200): { "result": 8 } 

    <h3 class="text-xl font-bold text-white mt-8 mb-4">Test Cases</h3>
TC IDScenarioInputExpected
    
TC0075 + 3 =5, +, 3, =Display: "8"
TC008Large numbers999+999Display: "1998"
TC009Decimal1.5+2.5Display: "4"

    Key Takeaways

    Why QUAD Works for Calculator (and ALL Projects)

  • Simple Projects = Big Wins
    • - Even a "simple" calculator has ~50 test cases - AI generates them in seconds vs hours manually
  • Human Brains for Human Decisions
    • - Is the UX intuitive? (Human gate) - Is the code secure? (Human gate) - Is it ready for production? (Human gate)
  • AI for Repetitive Work
    • - Scaffolding components - Writing test cases - Deploying to environments - Generating documentation
  • Documentation = Test Cases
    • - QA never asks "what should I test?" - Flow docs auto-generate test checklists

    Applying This to Your Project

    Step 1: Identify Your Human Gates

    Ask yourself:

  • • Who approves requirements?
  • • Who reviews code?
  • • Who signs off on QA?
  • • Who approves production?

    • Step 2: Identify AI Opportunities

    Look for:

  • • Repetitive coding patterns
  • • Standard test case generation
  • • Documentation updates
  • • Deployment automation

    • Step 3: Start Small

    Week 1-2: Enable Story Agent only Week 3-4: Add Dev Agent Week 5-6: Add Test Agents Week 7+: Full pipeline

    Related Documentation

  • • QUAD Summary - High-level overview
  • • QUAD Details - Technical specifications
  • • QUAD Jargons - Terminology
    • QUAD™ - A methodology by Suman Addanki | First Published: December 2025
    ←
    Back to
    All Documentation
    View Raw Markdown ↗