Countersign

@countersign/mcp

The cross-vendor kill switch + spend guard for AI agents — as MCP tools, inside any MCP client.

Countersign is a neutral control plane that holds one policy, one freeze, and one tamper-evident audit ledger across every agent-wallet backend at once. This package exposes it as Model Context Protocol tools, so an agent (or you, from chat in Claude / Cursor) can ask "may I spend this?" before acting — and freeze everything in under a second.

Tools

Tool	What it does
countersign_request_spend	Pre-flight guard — ask whether a spend is allowed before touching the wallet (allow / deny / needs_approval).
countersign_freeze	The kill switch — freeze every agent on every backend at once.
countersign_apply_policy	Apply one unified policy (caps, allow/deny lists, approval threshold) across all backends.
countersign_list_agents / countersign_health	See the governed fleet + control-plane health.
countersign_list_approvals / countersign_approve / countersign_deny	The human-approval queue.
countersign_ledger	Read + re-verify the append-only, hash-chained audit ledger.
countersign_unfreeze	Lift a freeze (recover).

Setup

It governs a running Countersign Core. The hosted Core at app.countersign.network is paused since 2026-09-18 and answers 503, so point this at a Core you run yourself. Set:

• COUNTERSIGN_URL — your Core, e.g. https://app.countersign.network
• COUNTERSIGN_API_KEY — required when the Core has auth enabled

Claude Desktop / Claude Code / Cursor

Add to your MCP config (claude_desktop_config.json, or claude mcp add, or Cursor's mcp.json):

{
  "mcpServers": {
    "countersign": {
      "command": "npx",
      "args": ["-y", "@countersign/mcp"],
      "env": {
        "COUNTERSIGN_URL": "https://app.countersign.network",
        "COUNTERSIGN_API_KEY": "csk_…"
      }
    }
  }
}

That's it — your agent now has the spend guard and the kill switch.

Show it (the "powered by" badge)

If Countersign guards your agent, say so — it tells users (and other agents) that spending is governed, and points the next operator at the same kill switch. Drop this in your README:

[![Spending governed by Countersign](https://img.shields.io/badge/spending%20governed%20by-Countersign-58e6a8?labelColor=0b1020)](https://countersign.network)

Listing in MCP registries (distribution)

Countersign spreads by being easy to discover wherever agent builders look for tools. The metadata below is ready to submit to the common registries — copy it as-is.

• Official MCP registry (registry.modelcontextprotocol.io / the mcp-registry repo) — entry:

  {
    "name": "io.github.countersign-network/countersign",
    "description": "Cross-vendor kill switch + spend guard for AI agents that spend money — one policy, one freeze, one tamper-evident ledger across every wallet/card backend.",
    "homepage": "https://countersign.network",
    "repository": "https://github.com/countersign-network/countersign",
    "packages": [
      { "registry": "npm", "name": "@countersign/mcp", "runtime": "npx" }
    ],
    "license": "Apache-2.0"
  }
  

• mcp.so — submit @countersign/mcp; category Finance / Security / Agents.
• Smithery — npx-launched server; env COUNTERSIGN_URL (default https://app.countersign.network) + optional COUNTERSIGN_API_KEY.
• awesome-mcp-servers lists — one-liner:

  Countersign — cross-vendor spend guard + sub-second kill switch + tamper-evident ledger for AI agents that move money (Coinbase, Turnkey, Openfort, Visa card). Testnet.

Standard listing fields:

Field	Value
Server id	countersign
Launch	npx -y @countersign/mcp
Tools	countersign_request_spend, countersign_freeze, countersign_apply_policy, countersign_list_agents, countersign_health, countersign_list_approvals, countersign_approve, countersign_deny, countersign_ledger, countersign_unfreeze
Tags	payments · security · kill-switch · spend-guard · agent-payments · wallet

Nothing here is auto-submitted — listings are made deliberately by a maintainer.

Apache-2.0. Countersign holds policy/freeze/ledger; it never takes custody of funds. Testnet only.