Grok CustomCat MCP by usefulapi customcat_get_shipping_cost
How to: Grok CustomCat MCP by usefulapi customcat_get_shipping_cost
Add CustomCat MCP by usefulapi to Grok
-
01
Open .mcp.json (in your project root) and merge this in. Keep any servers already there.
{
"mcpServers": {
"customcat": {
"type": "http",
"url": "https://customcat.usefulapi.io/mcp"
}
}
}-
02
Save the file and restart Grok.
-
03
Ask for something customcat_get_shipping_cost does. Grok lists the server's tools on connect and calls customcat_get_shipping_cost itself — you do not invoke it by name.
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04
If nothing happens, check the server is running and that CustomCat MCP by usefulapi's identifier in your config matches the one above exactly.
Grok Build reads Claude Code's .mcp.json and Claude Desktop's config unchanged, so a server you have already set up there needs nothing new. The Grok web app and X integration do not take custom servers. Grok docs
Same tool, other clients
This list was read from the server itself, by connecting to it and calling tools/list on 24 October 2026. It is what
the server actually exposes, not what its listing claims.
Mutating and Read-only are read off each tool's name, not its schema — a hint, not a guarantee. The registry stores tool names only; connect the server for its live schemas.