Aether Layer: EU VAT number validation (VIES) for ChatGPT

com.aether-layer/eu-vat-validate

Validates EU VAT numbers: local format/checksum for 27 states + XI, then VIES (cached 24 h).

client:ChatGPT transport:streamable-http tools:2

Install Aether Layer: EU VAT number validation (VIES) in ChatGPT

Settings → Connectors → Advanced → Developer mode

https://aether-layer.com/api/mcp?src=mcpreg

Custom connectors are a paid-plan feature and take a remote URL only. ChatGPT cannot run a packaged server locally. ChatGPT docs