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PayStage Preflight

Official registry Finance and payments

Evaluate x402 PaymentRequired against a local spending policy before an agent pays

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

Environment variables

  • PAYSTAGE_POLICY_PATH Path to policy.json spending rules

Documentation

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

Contents
  1. PayStage
  2. Packages
  3. Quick start
  4. Development
  5. License

PayStage

Local-first spending policy for AI agents that pay with x402. Decide before the agent pays: pay, review, or do_not_pay.

Packages

PackageDescription
@paystage/policyShared spending-policy schema and loader (parsePolicy, loadPolicy, humanToAtomic).
@paystage/preflightMCP server + CLI that evaluates an x402 PaymentRequired against a local policy.

Quick start

npx -y @paystage/preflight

Point it at a policy.json via PAYSTAGE_POLICY_PATH and wire it into Claude Desktop or Cursor as an MCP server. See packages/preflight/README.md for config snippets and an example policy.

Development

This is a monorepo using npm workspaces.

npm install
npm run build
npm test

License

MIT

Frequently asked questions

What is PayStage Preflight?

Evaluate x402 PaymentRequired against a local spending policy before an agent pays

How do I install PayStage Preflight?

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

Does PayStage Preflight 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 Preflight open source?

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

Who maintains PayStage Preflight?

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.