---
name: validate
description: Verify that an implementation plan was correctly executed by running each phase's success criteria against the working tree and producing a validation report. Use after the implement skill completes, when the user asks to "validate the plan", wants a post-implementation audit, or needs to confirm a feature is fully shipped per its plan.
argument-hint: [plan-path]
allowed-tools: Read, Bash(git *), Bash(make *), Glob, Grep, Agent
---

# Validate Plan

You are tasked with validating that an implementation plan was correctly executed, verifying all success criteria and identifying any deviations or issues.

## Initial Setup

When invoked:
1. **Determine context** - Are you in an existing conversation or starting fresh?
   - If existing: Review what was implemented in this session
   - If fresh: Need to discover what was done through git and codebase analysis

2. **Locate the plan**:
   - If plan path provided, use it
   - Otherwise, search recent commits for plan references or ask user

3. **Gather implementation evidence**:
   ```bash
   # Check recent commits
   git log --oneline -n 20
   git diff HEAD~N..HEAD  # Where N covers implementation commits

   # Run comprehensive checks
   cd $(git rev-parse --show-toplevel) && make check test
   ```

## Validation Process

### Step 1: Context Discovery

If starting fresh or need more context:

   **If the injected git context shows "not a git repo":**
   - Skip git-based evidence gathering (git log, git diff)
   - Validate via file inspection, automated test commands, and plan checklist
   - Note in report: "Git history unavailable — validation based on file inspection only"

1. **Read the implementation plan** completely
2. **Identify what should have changed**:
   - List all files that should be modified
   - Note all success criteria (automated and manual)
   - Identify key functionality to verify

3. **Spawn parallel research agents** to verify implementation:

   Spawn the agents below in parallel using the Agent tool. Wait for ALL agents to complete before proceeding.
   - **general-purpose** agent — Verify implementation details match plan specifications (analyzer role)
   - **general-purpose** agent — Verify implementation follows established codebase patterns (pattern-finder role)

   Example agent prompts:
   - "Analyze {component} and verify it implements {plan requirement} correctly"
   - "Find patterns similar to {new code} and check if conventions are followed"

   Also gather evidence directly:
   ```bash
   # Check recent commits
   git log --oneline -n 20
   git diff HEAD~N..HEAD  # Where N covers implementation commits

   # Run comprehensive checks
   cd $(git rev-parse --show-toplevel) && make check test
   ```

### Step 2: Systematic Validation

For each phase in the plan:

1. **Check completion status**:
   - Look for checkmarks in the plan (- [x])
   - Verify the actual code matches claimed completion

2. **Run automated verification**:
   - Execute each command from "Automated Verification"
   - Document pass/fail status
   - If failures, investigate root cause

3. **Assess manual criteria**:
   - List what needs manual testing
   - Provide clear steps for user verification

4. **Think deeply about edge cases**:
   - Were error conditions handled?
   - Are there missing validations?
   - Could the implementation break existing functionality?

### Step 3: Generate Validation Report

Create comprehensive validation summary:

```markdown
## Validation Report: {Plan Name}

### Implementation Status
✓ Phase 1: {Name} - Fully implemented
✓ Phase 2: {Name} - Fully implemented
⚠️ Phase 3: {Name} - Partially implemented (see issues)

### Automated Verification Results
✓ Build passes: `make build`
✓ Tests pass: `make test`
✗ Linting issues: `make lint` (3 warnings)

### Code Review Findings

#### Matches Plan:
- Database migration correctly adds {table}
- API endpoints implement specified methods
- Error handling follows plan

#### Deviations from Plan:
- Used different variable names in {file:line}
- Added extra validation in {file:line} (improvement)

#### Potential Issues:
- Missing index on foreign key could impact performance
- No rollback handling in migration

### Manual Testing Required:
1. UI functionality:
   - [ ] Verify {feature} appears correctly
   - [ ] Test error states with invalid input

2. Integration:
   - [ ] Confirm works with existing {component}
   - [ ] Check performance with large datasets

### Recommendations:
- Address linting warnings before merge
- Consider adding integration test for {scenario}
- Document new API endpoints

---

💬 Follow-up: if findings are localized, fix them and re-run `/skill:validate`. If findings imply plan-level changes, escalate to `/skill:revise <plan-path>` first.

**Next step:** `/skill:commit` — group the validated changes into atomic commits (skip if status is `needs_changes` — fix the gaps first, then re-run `/skill:validate`).

> 🆕 Tip: start a fresh session with `/new` first — chained skills work best with a clean context window.
```

## Handle Follow-ups

- **Validate does not edit code or plans.** It produces a report. Fixes happen in implement; plan revisions happen in revise.
- **Localized gaps.** If findings are small and localized, fix them in-place and re-run `/skill:validate` for a fresh report.
- **Plan-level gaps.** If findings imply the plan itself is wrong (missing phases, wrong approach, untestable success criteria), escalate to `/skill:revise <plan-path>` first, then re-implement, then re-validate.
- **No append mode.** Each validation run produces a fresh report — there is no `## Follow-up` append. The previous block's `Next step:` stays valid only when status is `complete`.

## Working with Existing Context

If you were part of the implementation:
- Review the conversation history
- Check your todo list for what was completed
- Focus validation on work done in this session
- Be honest about any shortcuts or incomplete items

## Important Guidelines

1. **Be thorough but practical** - Focus on what matters
2. **Run all automated checks** - Don't skip verification commands
3. **Document everything** - Both successes and issues
4. **Think critically** - Question if the implementation truly solves the problem
5. **Consider maintenance** - Will this be maintainable long-term?

## Validation Checklist

Always verify:
- [ ] All phases marked complete are actually done
- [ ] Automated tests pass
- [ ] Code follows existing patterns
- [ ] No regressions introduced
- [ ] Error handling is robust
- [ ] Documentation updated if needed
- [ ] Manual test steps are clear

## Relationship to Other Skills

Recommended workflow:
1. `/skill:implement` - Execute the implementation
2. `/skill:commit` - Create atomic commits for changes
3. `/skill:validate` - Verify implementation correctness

The validation works best after commits are made, as it can analyze the git history to understand what was implemented.

Remember: Good validation catches issues before they reach production. Be constructive but thorough in identifying gaps or improvements.
