# Phase 3: Validation Enhancement & Link Verification

**Planned Start**: April 17, 2026  
**Estimated Duration**: 5-7 days  
**Status**: Ready for Implementation  
**Owner**: Script Lead  

---

## Phase Objectives

Enhance validation script to detect and report on external resource integrity, documentation completeness, and future readiness for GitHub Skills directory listing.

### Success Criteria
- [ ] URL verification integrated into validation script
- [ ] WCAG criterion links validated
- [ ] Documentation link status reported
- [ ] Missing optional fields detected & reported
- [ ] Validation script exit code: 0 (all checks pass)
- [ ] Documentation updated with validation results
- [ ] No false positives on known good URLs

---

## Detailed Work Items

### 3.1: URL Verification Module
**Description**: Add HTTP/HTTPS link checking to validation workflow  
**Scope**:
- Detect URLs in SKILL.md descriptions (e.g., links to documentation)
- Perform HEAD requests with 5-second timeout
- Report status code (200 = OK, 404 = broken, timeout = unreachable)
- Cache results to avoid repeated requests
- Skip validation on CI environments (use --skip-url-checks flag)

**Acceptance Criteria**:
- [ ] Script detects all http/https URLs in skills
- [ ] Reports broken links with corrected URL suggestions
- [ ] Caches results in `.a11y-skill-link-cache.json`
- [ ] Timeout handling prevents CI pipeline stalls
- [ ] Output includes link health summary

**Estimated Effort**: 2 days

### 3.2: WCAG Criterion Mapping Validation
**Description**: Verify WCAG references in skill descriptions are accurate  
**Scope**:
- Detect WCAG criterion references (e.g., "2.4.3", "WCAG 2.2 AA")
- Match against official WCAG 2.2 criteria list
- Flag invalid criteria codes
- Verify conformance level claims

**Acceptance Criteria**:
- [ ] Detects all WCAG criterion formats
- [ ] Validates against official spec
- [ ] Reports mismatches with corrections
- [ ] Supports WCAG 2.1 and 2.2 references

**Estimated Effort**: 1.5 days

### 3.3: Documentation Link Validation
**Description**: Check skill documentation file integrity  
**Scope**:
- Verify referenced external resources exist (axe-core docs, Microsoft Office help, etc.)
- Check for broken markdown links within files
- Validate headings match table-of-contents structure
- Report documentation completeness score

**Acceptance Criteria**:
- [ ] Detects missing external resource links
- [ ] Reports documentation completeness
- [ ] Suggests required sections
- [ ] Cross-references against specification

**Estimated Effort**: 1.5 days

### 3.4: Optional Fields Detection
**Description**: Identify missing recommended fields for future specification  
**Scope**:
- Detect presence of optional fields (author, version, license)
- Report fields that will be required for GitHub Skills directory
- Suggest field templates and values
- Create remediation guide

**Acceptance Criteria**:
- [ ] Detects all optional fields
- [ ] Reports missing fields with templates
- [ ] Generates remediation priority matrix
- [ ] No false negatives on field presence

**Estimated Effort**: 1 day

### 3.5: Validation Script Enhancement
**Description**: Integrate all checks into existing validation script  
**Scope**:
- Add CLI flags: `--validate-urls`, `--validate-wcag`, `--skip-url-checks`
- Create structured JSON output format
- Maintain backward compatibility
- Add timing metrics

**Acceptance Criteria**:
- [ ] Script handles all new validation types
- [ ] Exit codes: 0=pass, 1=errors, 2=warnings only
- [ ] JSON output format stable
- [ ] No performance regression

**Estimated Effort**: 1 day

### 3.6: Documentation & Testing
**Description**: Document validation enhancements and test thoroughly  
**Scope**:
- Create PHASE-3-VALIDATION-REPORT.md with results
- Update scripts/validate-agents.js README
- Add integration tests
- Create troubleshooting guide

**Acceptance Criteria**:
- [ ] Documentation complete and clear
- [ ] Test coverage >90%
- [ ] No regressions from Phase 2
- [ ] Troubleshooting guide addresses common issues

**Estimated Effort**: 1 day

---

## Expected Output

### Validation Report Changes

**Before Phase 3**:
```
Errors: 0  Warnings: 0  Info: 25
```

**After Phase 3 (Proposed)**:
```
Errors: 0
Warnings: 0
Info: 25
Link Status: 25/25 verified (✓)
WCAG Mappings: 25/25 valid (✓)
Optional Fields: 0/25 missing (✓)
Documentation: 25/25 complete (✓)
```

### New Output: Link Health Summary
```
URL Verification Results:
  ✓ 47 URLs checked
  ✓ 47 URLs responding
  ✗ 0 URLs broken
  ⚠ 0 URLs timeout
  ✓ 100% link health
```

### New Output: Documentation Completeness
```
Documentation Audit:
  ✓ 25 skills have descriptions
  ✓ 25 skills have content sections
  ⚠ 0 skills missing external references
  ✓ Average documentation score: 95%
```

---

## Risk & Mitigation

| Risk | Likelihood | Impact | Mitigation |
|------|-----------|--------|-----------|
| Network timeouts during CI | Medium | High | Implement 5s timeout, `--skip-url-checks` flag for CI |
| Rate limiting from URL checker | Low | Medium | Implement caching, backoff strategy |
| False positives on valid URLs | Medium | Medium | Manual URL verification, whitelist known CDNs |
| Performance impact on validation | Low | High | Parallelize URL requests, async validation |

---

## Success Metrics

| Metric | Target | Status |
|--------|--------|--------|
| **All URLs Verified** | 100% | ⏳ Pending |
| **WCAG Mappings Valid** | 100% | ⏳ Pending |
| **Documentation Complete** | 100% | ⏳ Pending |
| **Validation Errors** | 0 | ⏳ Pending |
| **Validation Warnings** | 0 | ⏳ Pending |
| **Script Performance** | <5s for 25 skills | ⏳ Pending |

---

## Timeline

```
Apr 17  |---- URL Module (2d) ----|
Apr 19  |---- WCAG Validation (1.5d) ----|
Apr 21  |---- Doc Link Check (1.5d) ----|
Apr 22  |---- Optional Fields (1d) ----|
Apr 23  |---- Script Integration (1d) ----|
Apr 24  |---- Docs & Testing (1d) ----|
Apr 25  |✓ PHASE 3 COMPLETE
```

---

## Dependencies

### On Phase 2
- ✓ All skill descriptions <200 chars
- ✓ Validation script baseline: 0 errors, 0 warnings

### External
- Node.js http module (built-in)
- GitHub API (optional, for rate limit awareness)
- agentskills.io specification (for field mappings)

### Blocking Items
- None identified

---

## Phase 3 Completion Checklist

### Development
- [ ] URL verification module completed & tested
- [ ] WCAG criterion validation implemented
- [ ] Documentation link checking functional
- [ ] Optional field detection working
- [ ] All modules integrated into validate script
- [ ] No Phase 2 regressions detected

### Quality Assurance
- [ ] Integration tests passing (>90% coverage)
- [ ] Manual testing on 25 skills completed
- [ ] Performance benchmarked (<5s)
- [ ] Error messages clear & actionable
- [ ] Edge cases handled (timeouts, missing fields, etc.)

### Documentation
- [ ] PHASE-3-VALIDATION-REPORT.md created
- [ ] Script README updated
- [ ] Troubleshooting guide completed
- [ ] CLI flag documentation added

### Sign-off
- [ ] Code review approved
- [ ] QA sign-off obtained
- [ ] Documentation review completed

---

## Transition to Phase 4

**Trigger Condition**: Phase 3 complete with all checkboxes checked  
**Estimated Phase 4 Start**: April 25, 2026  
**Phase 4 Focus**: Supply chain security & signing

