Skill

vcsdd-spec-crystallization

Generates EARS-format requirements, purity boundary analysis, edge case enumeration, and spec validation checklists for VCSDD Phase 1a behavioral specifications.

documentation

code-quality

npx claudepluginhub sc30gsw/vcsdd-claude-code --plugin vcsdd

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This skill uses the workspace's default tool permissions.

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- Phase 1a of VCSDD pipeline (behavioral specification)

SKILL.md

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Last CommitApr 1, 2026

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VCSDD Spec Crystallization

When to Activate

Phase 1a of VCSDD pipeline (behavioral specification)
Writing EARS-format requirements
Identifying edge cases for a feature
Reviewing a behavioral spec for completeness

EARS Requirement Format

Every requirement MUST use EARS (Easy Approach to Requirements Syntax):

Pattern	Syntax	Example
Ubiquitous	THE SYSTEM SHALL [action]	THE SYSTEM SHALL log all authentication attempts
Event-driven	WHEN [trigger] THE SYSTEM SHALL [action]	WHEN user submits empty form THE SYSTEM SHALL return ErrorCode.EMPTY
State-driven	WHILE [state] THE SYSTEM SHALL [action]	WHILE user is authenticated THE SYSTEM SHALL display dashboard
Conditional	IF [condition] THEN THE SYSTEM SHALL [action]	IF retry count exceeds 3 THEN THE SYSTEM SHALL lock account
Optional	WHERE [feature] THE SYSTEM SHALL [action]	WHERE audit mode enabled THE SYSTEM SHALL record all reads

Spec Completeness Checklist

Every requirement has a unique ID (REQ-001, REQ-002, ...)
Every requirement uses EARS syntax
Every requirement is testable (can be pass/fail verified)
Edge case catalog includes: empty inputs, boundary values, concurrent access, error conditions
Non-functional requirements specified (performance bounds, security constraints)
Purity boundary identified: pure core vs effectful shell

Purity Boundary Analysis

Separate code into:

Pure Core: deterministic functions, no side effects, same input → same output always
- Example: parsing logic, business rules, validation, calculations
- Formally verifiable with Kani/hypothesis/fast-check
Effectful Shell: I/O, database, network, time, randomness
- Example: file readers, HTTP clients, database queries
- Tested with integration tests and mocks at the boundary

Edge Case Catalog Template

## Edge Cases

### Input Edge Cases
- Empty input: [expected behavior]
- Maximum length input: [expected behavior]
- Special characters / unicode: [expected behavior]
- Null / undefined: [expected behavior]

### State Edge Cases
- First-time run (no state): [expected behavior]
- Concurrent modification: [expected behavior]
- Interrupted operation: [expected behavior]

### Error Edge Cases
- External dependency unavailable: [expected behavior]
- Partial failure: [expected behavior]
- Timeout: [expected behavior]