FetchSandbox runs on your own machine — the client starts it, so there is no endpoint to ping. 1 014 installs a week from npm. Last commit 18 Sep 2026.
A deterministic verification engine for agents. Proves a fix: fails on the old code, passes on new.
Today is the operative word: we check FetchSandbox every 15 minutes and re-read its code on every release. Watch it and you find out the day that stops being true.
This server runs on your own machine — install it with the package manager and the client starts it for you. Package name taken from the official registry entry.
claude mcp add mcp -- npx -y fetchsandbox-mcp
{
"mcpServers": {
"mcp": {
"args": [
"-y",
"fetchsandbox-mcp"
],
"command": "npx"
}
}
}
[mcp_servers.mcp]
command = "npx"
args = ["-y", "fetchsandbox-mcp"]
{
"mcpServers": {
"mcp": {
"args": [
"-y",
"fetchsandbox-mcp"
],
"command": "npx"
}
}
}
{
"mcpServers": {
"mcp": {
"args": [
"-y",
"fetchsandbox-mcp"
],
"command": "npx"
}
}
}
This one needs environment variables set before it will start:
FETCHSANDBOX_API_KEY (Optional. Sign in without a browser — useful in CI. Left unset, the server runs anonymously and asks you to sign in the first time a run produces a receipt.), FETCHSANDBOX_TELEMETRY (Set to '0' to disable anonymous usage telemetry.), FETCHSANDBOX_BASE_URL (Override the FetchSandbox backend base URL (defaults to https://fetchsandbox.com). Useful for stage/self-hosted testing.).
The author declared them in the registry entry; get the values from the project itself.
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Answers built from our own checks of this server.