Grok 402MCP.org — HTTP 402 & Agent Payment Registry Prompt/choose_payment_rail
How to: Grok 402MCP.org — HTTP 402 & Agent Payment Registry choose_payment_rail
Add 402MCP.org — HTTP 402 & Agent Payment Registry to Grok
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01
Open .mcp.json (in your project root) and merge this in. Keep any servers already there.
{
"mcpServers": {
"registry": {
"type": "http",
"url": "https://402mcp.org/api/v1/mcp"
}
}
}-
02
Save the file and restart Grok.
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03
choose_payment_rail is surfaced in the client's prompt or command menu. Unlike a tool, you invoke it deliberately — Grok will not call it for you.
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04
If it does not appear, check that 402MCP.org — HTTP 402 & Agent Payment Registry is connected and that you are looking at its prompts rather than its tools.
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
Set these first
402MCP.org — HTTP 402 & Agent Payment Registry will not start until these are set, so it never reaches Grok.
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MCP_402_OFFLINE
Same prompt, other clients
Read from the server itself, by connecting to it and calling prompts/list on 16 October 2026.
A listing does not declare its prompts, 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 prompt's arguments.