Grok FetchSandbox prove_fix
How to: Grok FetchSandbox prove_fix
Add FetchSandbox to Grok
-
01
Open .mcp.json (in your project root) and merge this in. Keep any servers already there.
{
"mcpServers": {
"mcp": {
"type": "http",
"url": "https://fetchsandbox.com/mcp/v1"
}
}
}-
02
Save the file and restart Grok.
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03
Ask for something prove_fix does. Grok lists the server's tools on connect and calls prove_fix itself — you do not invoke it by name.
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04
If nothing happens, check the server is running and that FetchSandbox'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
Set these first
FetchSandbox will not start until these are set, so prove_fix never becomes available.
-
FETCHSANDBOX_API_KEY -
FETCHSANDBOX_TELEMETRY -
FETCHSANDBOX_BASE_URL
Same tool, other clients
This list was read from the server itself, by connecting to it and calling tools/list on 24 September 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.