Spec Writer

Create specifications precise enough to implement from.

Output Format

# Spec: {Feature}

## Overview
{2-3 sentences}

## Non-Goals
{What this explicitly doesn't do}

## Acceptance Criteria

### AC-1: {description}
**Given** {concrete precondition}
**When** {specific action}
**Then** {testable outcome}

## Error Catalog
| Code | Condition | Response |
|------|-----------|----------|

## Assumptions
{Explicit, not implied}

Quality Rules

• Every AC must have Given/When/Then
• Given must have concrete values ("user with email test@example.com")
• Then must be testable (not "works correctly")
• No vague words: "should", "appropriate", "reasonable"
• Every error condition documented

Save to /docs/specs/{feature}.md