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PayStage Auth Watch

Official registry Security

Read-only MCP tools to list and flag outstanding ERC-20, Permit2, and EIP-3009 auths

Source code Website Documentation

Install

Add this to your client's MCP configuration (Claude Desktop: claude_desktop_config.json; Cursor: .cursor/mcp.json; VS Code and others use the same "mcpServers" shape).

NPM package @paystage/auth-watch
Claude Code 
claude mcp add paystage-auth-watch -e 'PAYSTAGE_POLICY_PATH=<PAYSTAGE_POLICY_PATH>' -e 'PAYSTAGE_RPC_URL=<PAYSTAGE_RPC_URL>' -- npx -y @paystage/auth-watch@0.1.0
JSON configuration (Claude Desktop, Cursor, VS Code) 
{
    "mcpServers": {
        "paystage-auth-watch": {
            "command": "npx",
            "args": [
                "-y",
                "@paystage/auth-watch@0.1.0"
            ],
            "env": {
                "PAYSTAGE_POLICY_PATH": "<PAYSTAGE_POLICY_PATH>",
                "PAYSTAGE_RPC_URL": "<PAYSTAGE_RPC_URL>"
            }
        }
    }
}

Environment variables

  • PAYSTAGE_POLICY_PATH Path to policy.json spending rules
  • PAYSTAGE_RPC_URL Base RPC URL override

Documentation

From the project's README on GitHub, refreshed weekly. Links open on GitHub.

Contents
  1. PayStage
  2. Quick start
  3. Configure
  4. Tools
  5. Packages
  6. Links
  7. Development
  8. License

PayStage

Safety tools for AI agent payments (x402 + MCP).

PayStage sits in front of an agent's wallet and answers one question before money moves: should this payment happen? Tools return pay, review, or do_not_pay.

Quick start

npx -y @paystage/mcp

@paystage/mcp is the umbrella MCP server. It exposes the PayStage tools over stdio and reads a local policy file.

Configure

Claude Desktop (claude_desktop_config.json):

{
  "mcpServers": {
    "paystage": {
      "command": "npx",
      "args": ["-y", "@paystage/mcp"],
      "env": {
        "PAYSTAGE_POLICY_PATH": "/absolute/path/to/policy.json",
        "PAYSTAGE_RPC_URL": "https://mainnet.base.org"
      }
    }
  }
}

Cursor (.cursor/mcp.json):

{
  "mcpServers": {
    "paystage": {
      "command": "npx",
      "args": ["-y", "@paystage/mcp"],
      "env": {
        "PAYSTAGE_POLICY_PATH": "/absolute/path/to/policy.json",
        "PAYSTAGE_RPC_URL": "https://mainnet.base.org"
      }
    }
  }
}
  • PAYSTAGE_POLICY_PATH (required): path to your local policy.json.
  • PAYSTAGE_RPC_URL (optional): RPC endpoint used by on-chain checks. Defaults to a public Base RPC.

Tools

ToolStatusWhat it does
evaluate_mcp_paymentAvailable nowEvaluates a proposed x402 payment against the local policy and returns pay, review, or do_not_pay.
list_outstanding_authsAvailable nowLists payments that are authorized but not yet settled.
evaluate_outstanding_authsAvailable nowEvaluates outstanding authorizations and flags double-pay or limbo risk.

Packages

PackageRoleLinks
@paystage/mcpUmbrella MCP server (start here)npm
@paystage/preflightMCP payment preflightnpm
@paystage/auth-watchOutstanding-auth watchnpm
@paystage/policyPolicy parsing and evaluationnpm

Development

This is a monorepo.

pnpm install
pnpm build
pnpm test
pnpm lint

License

MIT

Frequently asked questions

What is PayStage Auth Watch?

Read-only MCP tools to list and flag outstanding ERC-20, Permit2, and EIP-3009 auths

How do I install PayStage Auth Watch?

It runs on your machine. In Claude Code: claude mcp add paystage-auth-watch -e 'PAYSTAGE_POLICY_PATH=<PAYSTAGE_POLICY_PATH>' -e 'PAYSTAGE_RPC_URL=<PAYSTAGE_RPC_URL>' -- npx -y @paystage/auth-watch@0.1.0. For other clients, paste the JSON configuration from this page into their MCP settings.

Does PayStage Auth Watch need an API key?

Its registry entry lists no required key or secret. Some features may still need an account with the service it connects to.

Is PayStage Auth Watch open source?

Yes. Its code is on GitHub under the MIT license.

Who maintains PayStage Auth Watch?

It is published by base-buzz. AI.tn lists it but does not maintain or endorse it.

From the official MCP Registry. Listing is not an endorsement: review a server's code and permissions before giving it access to your data.