name: prd-implementation-precheck
description: Implement PRDs/specs with a mandatory precheck review before coding. Use when a user asks to implement a PRD/feature spec/requirements doc or says "implement PRD/spec". Perform a preflight review, raise questions on scope/consistency/risks, then implement after confirmation.
allowed-tools: Read, Write, Edit, Bash, Grep, Glob, AskUserQuestion
metadata:
hooks:
after_complete:
- trigger: self-improving-agent
mode: background
reason: "Learn from implementation patterns"
- trigger: session-logger
mode: auto
reason: "Log PRD implementation activity"

PRD Implementation Precheck

Overview

Perform a short PRD precheck, present issues and questions, then implement only after the user confirms or adjusts the PRD.

Workflow

1. Locate the PRD and any referenced files.
2. Precheck the PRD and summarize intent in 1-2 sentences.
3. List findings and questions (blockers first), then ask for confirmation to proceed.
4. After confirmation, implement the PRD with minimal, consistent changes.
5. Validate (tests or manual steps) or state what was not run.

Precheck Checklist

Basic Checks

• Scope: Identify over-broad changes; suggest a smaller, targeted approach.
• Alignment: Flag conflicts with existing patterns or architecture; propose alternatives.
• Dependencies: Note missing hooks/providers/data sources or unclear ownership.
• Behavior: Verify flows and edge cases are specified; ask for gaps.
• Risks: Call out performance, regressions, or migration risks.
• Testing: Check success criteria and test coverage; request specifics if vague.

Edge Case Coverage Checks

Verify the PRD addresses these edge cases (mark as ⚠️ if missing):

Data Boundaries

• [ ] Null/Empty handling - What happens with empty inputs or null values?
• [ ] Boundary values - Are min/max limits defined? What happens at boundaries?
• [ ] Duplicate data - How are duplicates detected and handled?
• [ ] Data format - Are input formats validated? What about special characters?

State Boundaries

• [ ] State transitions - Are all valid state transitions defined?
• [ ] Invalid transitions - What happens on illegal state changes?
• [ ] Concurrent modifications - How are simultaneous edits handled?
• [ ] Rollback scenarios - Can operations be undone? How?

Error Boundaries

• [ ] Network failures - What happens when API calls fail?
• [ ] Timeout behavior - Are timeouts defined? What's the retry strategy?
• [ ] Partial failures - If step 2 of 3 fails, what happens to step 1?
• [ ] Error messages - Are user-facing error messages defined?

UX Boundaries

• [ ] Empty states - What does the user see with no data?
• [ ] Loading states - How is loading indicated?
• [ ] Success feedback - How does the user know the action succeeded?
• [ ] Permission denied - What happens when user lacks permission?

Codebase Consistency Checks

Scan the codebase to verify PRD aligns with existing patterns:

# Check if PRD's proposed patterns match existing code
grep -r "pattern_from_prd" src/ --include="*.ts"

• [ ] Delete strategy - Does PRD match existing soft/hard delete pattern?
• [ ] Error handling - Does PRD use the same error display mechanism?
• [ ] Component reuse - Does PRD leverage existing components?
• [ ] API patterns - Does PRD follow existing API conventions?

Output Format

Precheck Report Template

## PRD Precheck Report

### Summary
{1-2 sentence summary of what the PRD aims to achieve}

### ✅ Covered Edge Cases
- {List edge cases that are well-defined in the PRD}

### ⚠️ Missing Edge Cases
| Edge Case | Category | Suggested Default | Needs Confirmation |
|-----------|----------|-------------------|-------------------|
| Empty list display | UX | Use existing EmptyState | No |
| Concurrent edit | State | Last write wins | **Yes** |

### 🔴 Blockers
- {Critical issues that must be resolved before implementation}

### 🟡 Warnings
- {Non-critical issues that should be addressed}

### Questions for User
1. {Specific question about missing edge case}
2. {Specific question about ambiguous requirement}

---

**Proceed as-is, or update the PRD?**

Output Expectations

• Provide a concise precheck report with questions and risks.
• Ask explicitly: "Proceed as-is, or update the PRD?"
• If no blockers, state assumptions and continue only with user approval.