MCP validate_vast Passes the XML the Agent Pasted. The Live Tag URL Still Has Wrappers

说明与用途

代理仅验证粘贴的 VAST XML，忽略实时标签 URL，导致 VAST 错误。添加单独的 URL 验证和包装链检查可解决问题。

问题

A buyer agent validates pasted VAST XML with MCP validate_vast, but trafficking fails because the live tag URL contains wrappers that were not validated.

结果

By separating paste validation from URL validation and explicitly checking wrapper chains, trafficking failures due to unseen wrappers are prevented.

工作流

• 1. Agent receives VAST XML or URL from ticket.
• 2. If XML only, agent asks for serving URI; if URL present, proceed to URL validation.
• 3. Open VAST tag tester with live URL to fetch current response and preview creative.
• 4. If wrappers detected, run VAST inspector hop‑by‑hop to identify chain breaks.
• 5. In agent pipeline, choose tool: validate_vast_url or inspect_vast(url) for URLs; validate_vast(xml) only for in‑memory XML and do not mark trafficking ready.
• 6. CLI/CI run vastlint validate on files and vastlint inspect <url> for chains.
• 7. Use rule reference and validate VAST XML guide to decide on paste vs URL validation and wrapper depth.

证据

Agents wired only to validate_vast inherit that ceiling even when the user says "validate this tag."

来源

I treat paste validation and URL validation as separate gates.

来源

When the tester shows wrappers, I run the same URL through the VAST inspector hop by hop.

来源