Countersign runs on your own machine — the client starts it, so there is no endpoint to ping. 76 installs a week from npm. Last commit 18 Sep 2026.
Kill switch + spend guard for AI agents that spend money, across every wallet vendor at once.
What the code does
We read the source, 6 d ago · rules 995398eba69f
What this server is able to do. For an MCP server this is often the job itself — a terminal server runs commands because that is what it is for. Listed so you know what you are plugging in, not as an accusation.
const emitted = (p) => path.join(root, ".dts", p);
Is this your server and something here is wrong? Tell us — corrections are free and do not require a plan.
This code can reach further than it looks
We found places where it runs commands, builds paths or queries from values it is given. None of that is a flaw by itself — it becomes one when the code changes, and code changes quietly between releases. We re-read it on every one.
Connect this server
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 countersign -e 'COUNTERSIGN_URL=<COUNTERSIGN_URL>' -e 'COUNTERSIGN_API_KEY=<COUNTERSIGN_API_KEY>' -- npx -y @countersign/mcp{
"mcpServers": {
"countersign": {
"command": "npx",
"args": [
"-y",
"@countersign/mcp"
],
"env": {
"COUNTERSIGN_API_KEY": "<COUNTERSIGN_API_KEY>",
"COUNTERSIGN_URL": "<COUNTERSIGN_URL>"
}
}
}
}[mcp_servers.countersign]
command = "npx"
args = ["-y", "@countersign/mcp"]
env = { COUNTERSIGN_URL = "<COUNTERSIGN_URL>", COUNTERSIGN_API_KEY = "<COUNTERSIGN_API_KEY>" }{
"mcpServers": {
"countersign": {
"command": "npx",
"args": [
"-y",
"@countersign/mcp"
],
"env": {
"COUNTERSIGN_API_KEY": "<COUNTERSIGN_API_KEY>",
"COUNTERSIGN_URL": "<COUNTERSIGN_URL>"
}
}
}
}{
"servers": {
"countersign": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"@countersign/mcp"
],
"env": {
"COUNTERSIGN_API_KEY": "<COUNTERSIGN_API_KEY>",
"COUNTERSIGN_URL": "<COUNTERSIGN_URL>"
}
}
}
}Put your own values in place of
<COUNTERSIGN_URL> (Base URL of the Countersign Core to govern (hosted or self-hosted)), <COUNTERSIGN_API_KEY> (API key for the Core (self-serve one at https://app.countersign.network/start or POST /signup)).
The author’s registry entry marks them as required.
Alternatives to Countersign
same job, measured the same wayA guarded wallet for AI agents on Robinhood Chain: a spending policy runs before every signature.
Wallets and rails that let AI agents spend money safely.
Task envelope, budget ledger, kill switch and signed receipts for agents that pay.
Local spend caps, kill-switch blocking and Ed25519-signed receipts for AI agent tool calls.
Persistent memory for AI agents: keyed facts, a wake bundle each session, one memory in every model.
Spend limits for AI agents that pay with x402: every paywall is policy-checked before a cent moves.
Wallet for AI agents with on-chain spending limits and owner approval over the limit
Email API for apps and AI agents: budgets per key, a kill switch, refusals that name the fix.
Countersign — questions
Answers built from our own checks of this server.