MUSUBIX EARS Validation Skill

This skill helps you create and validate requirements using EARS (Easy Approach to Requirements Syntax) format.

EARS Pattern Reference

1. Ubiquitous Pattern

Use for: Requirements that must always be satisfied.

Syntax:

THE [system name] SHALL [requirement]

Example:

THE AuthService SHALL authenticate users with valid credentials.

2. Event-Driven Pattern

Use for: Requirements triggered by specific events.

Syntax:

WHEN [trigger event], THE [system name] SHALL [response]

Example:

WHEN a user submits login credentials, THE AuthService SHALL validate the credentials within 2 seconds.

3. State-Driven Pattern

Use for: Requirements that apply while in a specific state.

Syntax:

WHILE [system state], THE [system name] SHALL [behavior]

Example:

WHILE the system is in maintenance mode, THE API SHALL return 503 Service Unavailable.

4. Unwanted Behavior Pattern

Use for: Behaviors that must be prevented.

Syntax:

THE [system name] SHALL NOT [unwanted behavior]

Example:

THE AuthService SHALL NOT store passwords in plain text.

5. Optional Pattern

Use for: Conditional requirements.

Syntax:

IF [condition], THEN THE [system name] SHALL [response]

Example:

IF two-factor authentication is enabled, THEN THE AuthService SHALL require a verification code.

Validation Checklist

When validating EARS requirements, check:

• Pattern Compliance: Does it follow one of the 5 EARS patterns?
• System Name: Is the system/component clearly identified?
• SHALL Keyword: Is "SHALL" used for mandatory requirements?
• Measurable: Is the requirement testable and measurable?
• Atomic: Does it describe a single requirement?
• No Ambiguity: Is the language clear and unambiguous?

CLI Commands

# Validate EARS syntax
npx musubix requirements validate <file>

# Convert natural language to EARS
npx musubix requirements analyze <file>

# Map to ontology
npx musubix requirements map <file>

Conversion Examples

Natural Language → EARS

Input: "Users should be able to login"

Output:

THE AuthenticationModule SHALL authenticate users with valid credentials.

Input: "Show error when password is wrong"

Output:

WHEN invalid credentials are provided, THE AuthenticationModule SHALL display an error message.

Input: "Don't allow SQL injection"

Output:

THE InputValidator SHALL NOT accept input containing SQL injection patterns.

Priority Levels

Priority	Description	Usage
P0	必須 (Must Have)	Release blocker
P1	重要 (Should Have)	Implement if possible
P2	任意 (Nice to Have)	Time permitting

Requirement Document Template

### REQ-[CATEGORY]-[NUMBER]: [Title]

**種別**: [UBIQUITOUS|EVENT-DRIVEN|STATE-DRIVEN|UNWANTED|OPTIONAL]
**優先度**: [P0|P1|P2]

**要件**:
[EARS形式の要件文]

**検証方法**: [Unit Test|Integration Test|E2E Test|Manual]
**受入基準**:
- [ ] Criterion 1
- [ ] Criterion 2

**トレーサビリティ**: DES-XXX, TEST-XXX
**憲法準拠**: Article IV (EARS Format)

Common Mistakes to Avoid

1. ❌ Using "should" instead of "SHALL"
2. ❌ Combining multiple requirements in one statement
3. ❌ Vague or unmeasurable criteria
4. ❌ Missing system name
5. ❌ Using implementation details in requirements