---
name: freewheel-vast-validator
description: "Validate VAST and VPAID tags, wrappers, tracking, and playback."
version: 2.0.0
author: Hermes Agent (rebuild)
license: Proprietary site content
platforms: [linux, macos, windows]
metadata:
  hermes:
    tags: [FreeWheel, Implementation, QA, Operations]
    related_skills: []
---

# FreeWheel VAST Validator

Use for validating VAST/VPAID ad tags, testing ad responses, diagnosing errors, and ensuring creative compliance before campaign launch.

## VAST Standards

- **VAST 3.0** — standard ad response XML format
- **VAST 4.0/4.1** — extended features, companion ads, tracking
- **VPAID** — interactive ad format with JavaScript
- **VAST Click tracking** — impression, click, completion tracking
- **Ad verification integration** — MOAT, DoubleVerify, IAS tracking

## Tag Validation

- **XML syntax** — VAST response structure validation
- **Ad wrapper chains** — validate wrapper-to-wrapper chain
- **Video ads** — validate video ad elements, codecs, sizing
- **Companion ads** — validate companion banner elements
- **Tracking events** — validate impression/click/completion tracking
- **Error codes** — diagnose VAST error codes (200-500+ range)

## Error Diagnosis

- **200 series** — VAST parsing errors (malformed XML)
- **300 series** — Ad serving errors (creative unavailable)
- **400 series** — Ad response errors (tracking failures)
- **500 series** — Ad execution errors (VPAID failures)
- **Wrapper chain errors** — broken or circular wrapper chains
- **Tracking errors** — missing or invalid tracking URLs

## Workflow

### Validate VAST Tag
1. Submit VAST tag URL or XML for validation
2. Check XML syntax against VAST schema
3. Validate ad wrapper chain (if applicable)
4. Check video ad elements (codecs, sizing, duration)
5. Verify tracking event URLs
6. Test companion ad elements
7. Flag errors and issues with severity

### Test Ad Response
1. Submit tag to FreeWheel test environment
2. Execute ad response through decisioning engine
3. Monitor tracking events during execution
4. Verify VPAID ad execution (if applicable)
5. Check companion ad delivery
6. Record errors and response time

### Fix Tag Issues
- **XML syntax errors** — regenerate VAST response
- **Missing tracking** — add tracking URLs
- **VPAID failures** — debug JavaScript execution
- **Wrapper chain errors** — fix wrapper order
- **Tracking URL errors** — verify URL format and accessibility
- **Creative unavailable** — check creative status in ad server

## Key Metrics
- **Tag validation pass rate** — % of tags passing validation
- **Ad response success rate** — % of tags executing successfully
- **Wrapper chain depth** — average wrapper chain length
- **Tracking event coverage** — % of tracking events present
- **VPAID execution rate** — % of VPAID ads executing correctly
- **Response time** — average tag response latency

## Notes
- Always validate tags before campaign launch
- VPAID tags require JavaScript execution testing
- Wrapper chains should not exceed 5 levels
- Tracking URLs must be accessible and properly formatted
- VAST 4.1 features require FreeWheel platform support
- Use FreeWheel test environment for tag testing
- Tag validation is mandatory for all new creatives

## Inputs and Boundaries

- Require the account, environment, campaign or integration identifiers, requested operation, date range, and applicable platform specification.
- Default to read-only inspection or sandbox execution. Require explicit approval before production changes, automation writes, DNS changes, inventory changes, or launch actions.
- Validate user-provided URLs, XML, files, identifiers, and configuration before processing.
- Never expose credentials, tokens, client secrets, or unnecessary PII in logs, reports, test fixtures, or generated artifacts.

## Failure Handling

- Record the exact input, environment, operation, timestamp, response, and correlation ID when available.
- Classify failures as malformed input, unsupported format, authentication, permission, dependency, timeout, platform, or verification failure.
- Do not repeat mutations blindly. Check for partial completion and current state before retrying.
- Stop and escalate when a production, security, compliance, delivery, or rollback gate fails.

## Verification

- Confirm every requested item was checked and report pass, fail, or warning per item.
- Read back the authoritative configuration after approved changes.
- Run the relevant sandbox, integration, delivery, playback, routing, or health check.
- Preserve evidence and report assumptions, approvals, unresolved risks, rollback status, and next actions.