# Validation hygiene (use existing validators)

> Whether structured data, feeds, and protocol manifests are run through existing maintained validators rather than a homegrown checker.

<!-- Canonical: https://agentmint.net/signals/validation-hygiene/ · Signal in the AgentMint.net Signals Database · Evidence: spec-fact (Very high confidence) · Last verified 2026-07-08 · Evidence types are load-bearing: spec-fact | reported | hypothesis (no measured). -->

- **Affects (funnel stage):** Matching
- **Evidence:** spec-fact
- **Confidence:** Very high
- **Impact:** 2/3
- **Status:** active
- **Last verified:** 2026-07-08

## Per-platform status

Undocumented platforms show "unknown" - honest unknowns, never invented.

| Platform | Status | Notes | Source |
| --- | --- | --- | --- |
| ChatGPT | unknown | Not documented by this platform. | - |
| Gemini / Google AI Mode | unknown | Not documented by this platform. | - |
| Perplexity | unknown | Not documented by this platform. | - |
| Copilot | unknown | Not documented by this platform. | - |
| Claude | unknown | Not documented by this platform. | - |

## Evidence and sources

- [Merchant listing structured data](https://developers.google.com/search/docs/appearance/structured-data/merchant-listing) (2026-07-08)
- [ucptools.dev: UCP/ACP validator](https://ucptools.dev) (2026-07-08)

## How to act on this

Run the Rich Results Test, Schema.org validator, Merchant Center diagnostics, and a maintained UCP/ACP validator on every deploy; fix every error, then triage warnings.

### Related checklist items
- [Validate structured data with the Rich Results Test / Schema.org validator and the feed with Merchant Center diagnostics.](https://agentmint.net/tools/agentic-readiness-checklist/#a-structured-data-05) (Readiness)
- [Validate protocol manifests with existing validators; don't build your own.](https://agentmint.net/tools/agentic-readiness-checklist/#a-protocol-presence-03) (Readiness)

### Handbook chapters
- [Information Density: Facts Per Token on Machine Surfaces](https://agentmint.net/handbook/information-density/)

### Related signals
- [Offer markup completeness and truthfulness](https://agentmint.net/signals/offer-markup-completeness/)
- [UCP profile and order-management readiness](https://agentmint.net/signals/ucp-readiness/)
- [ACP feed and checkout readiness](https://agentmint.net/signals/acp-readiness/)