Postcard for ChatGPT

com.clawhard/postcard

Check a link's share card on X, Facebook, LinkedIn: real image size, tag problems, fixed tags.

client:ChatGPT transport:streamable-http tools:2

Install Postcard in ChatGPT

Settings → Connectors → Advanced → Developer mode

https://postcard.clawhard.com/mcp

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