vc-scenario - SKILL.md Agent Skill

name: vc:scenario description: "Generate comprehensive edge cases and test scenarios by decomposing features across 12 dimensions. Use before implementation or testing to catch issues early." argument-hint: "" metadata: author: claudekit attribution: "Scenario exploration pattern adapted from autoresearch by Udit Goenka (MIT)" license: MIT version: "1.0.0"

vc:scenario — Edge Case & Scenario Explorer

Decompose any feature or code path across 12 dimensions to surface edge cases, risks, and test targets before implementation begins.

When to Use

Before implementing complex or stateful features
Before writing tests (generates test targets)
Risk assessment during planning or code review
API design review — surface contract edge cases early

When NOT to Use

Trivial single-line changes or cosmetic UI tweaks
Already well-tested, stable code with no recent modifications
Pure configuration changes with no logic paths

12 Decomposition Dimensions

Not all 12 apply to every feature. Identify relevant dimensions first, then generate scenarios only for those.

#	Dimension	What to Look For
1	User Types	admin, guest, banned, new user, power user, bot/scraper
2	Input Extremes	empty, null, max length, unicode, special chars, SQL/script injection
3	Timing	concurrent access, race conditions, timeout, slow network, retry storms
4	Scale	0 items, 1 item, 1M items, pagination boundary, cursor wrap
5	State Transitions	first use, mid-flow abort, resume after crash, partial completion
6	Environment	mobile/low-end CPU, no JS, screen reader, proxy/VPN, different timezone/locale
7	Error Cascades	DB down, API timeout, disk full, OOM, network partition, partial write
8	Authorization	expired token, wrong role, shared/public link, CORS, CSRF, privilege escalation
9	Data Integrity	duplicate entries, orphan references, encoding mismatch, concurrent schema migration
10	Integration	webhook replay, API version mismatch, third-party outage, contract drift
11	Compliance	GDPR deletion request, audit logging gap, data retention, accidental PII exposure
12	Business Logic	edge pricing (zero/negative), coupon stacking, refund after partial delivery, free tier limits

Workflow

Read target file(s) or parse feature description from argument
Filter dimensions — mark which of the 12 apply; skip irrelevant ones explicitly
Generate 3–5 scenarios per relevant dimension
Categorize severity — Critical / High / Medium / Low
Output as structured table (see format below)
Summarize total scenario count by severity

Severity Criteria

Level	Meaning
Critical	Data loss, security breach, auth bypass, silent corruption
High	Feature broken for a subset of users, data inconsistency
Medium	Degraded UX, recoverable error not surfaced to user
Low	Minor visual glitch, non-blocking warning

Output Format

## Scenario Report: [target]

Dimensions analyzed: [list]
Dimensions skipped: [list + reason]

| # | Dimension | Scenario | Severity | Expected Behavior |
|---|-----------|----------|----------|-------------------|
| 1 | Input Extremes | Empty string for required name field | High | Return 400 with field error |
| 2 | Authorization | Expired JWT accessing protected route | Critical | Redirect to login, invalidate session |
| 3 | Timing | Two users submit same form simultaneously | High | Idempotency key or conflict error |

### Summary
- Critical: N
- High: N
- Medium: N
- Low: N
- Total: N scenarios across X dimensions

Integration with Other Skills

Next Step	Skill	How
Generate test cases from scenarios	`vc:test`	Pass scenario table as input context
Inform implementation plan risks	`generate-plan` / `plan-agent`	Paste Critical/High rows into risk assessment
Deep persona debate on top risks	`vc:predict`	Feed Critical scenarios as the change proposal

Example Invocations

/vc:scenario src/api/payment.ts
/vc:scenario "User registration with OAuth providers"
/vc:scenario src/middleware/auth.ts
/vc:scenario "Add multi-tenancy to the database layer"