ChatGPT Card Mailer Resource/Card Mailer widget
How to: ChatGPT Card Mailer Card Mailer widget
Add Card Mailer to ChatGPT
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01
Open Settings → Connectors → Advanced → Developer mode and merge this in. Keep any servers already there.
https://cards.onmax.me/mcp-
02
Save the file and restart ChatGPT.
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03
Card Mailer widget is surfaced wherever your client lets you attach context. It is context to attach, not an action to run.
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04
If it does not appear, check that Card Mailer is connected and that you are looking at its resources rather than its tools.
Custom connectors are a paid-plan feature and take a remote URL only. ChatGPT cannot run a packaged server locally. ChatGPT docs
Same resource, other clients
Read from the server itself, by connecting to it and calling resources/list on 22 October 2026.
A listing does not declare its resources, so asking is the only way to know them, and this
is what the server actually offers rather than what its listing claims. Names only are
stored; connect the server for each resource's type and contents.