MCP Hub
Back to servers

pop-pay

Point One Percent - Semantic Payment Guardrail for AI Agents. It only takes 0.1% of hallucination to drain 100% of your wallet.

npm190/wk
Forks
1
Updated
Apr 9, 2026

Quick Install

npx -y pop-pay

npm version License: MIT CI Node.js

Point One Percent (AgentPay)

Point One Percent — pop-pay

it only takes 0.1% of Hallucination to drain 100% of your wallet.

The runtime security layer for AI agent commerce. Card credentials are injected directly into the browser DOM via CDP — they never enter the agent's context window. One hallucinated prompt can't drain a wallet it can't see.

Getting Started

1. Initialize the credential vault

npx -y pop-pay pop-init-vault

This encrypts your card credentials into ~/.config/pop-pay/vault.enc (AES-256-GCM). The MCP server decrypts automatically at startup.

For stronger protection (recommended — blocks agents with shell access):

npx -y pop-pay pop-init-vault --passphrase   # one-time setup
npx -y pop-pay pop-unlock                     # run once before each session

2. Add to your MCP client

Standard config for any MCP-compatible client:

{
  "mcpServers": {
    "pop-pay": {
      "command": "npx",
      "args": ["-y", "pop-pay", "launch-mcp"],
      "env": {
        "POP_CDP_URL": "http://localhost:9222"
      }
    }
  }
}

Install in VS Code Install in VS Code Insiders Install in Cursor

Claude Code

Claude Code uses its own CLI — the JSON config above is not needed.

claude mcp add --scope user pop-pay -- npx -y pop-pay launch-mcp

--scope user makes it available across all projects. To remove: claude mcp remove pop-pay

Cursor / Windsurf / VS Code

Add the JSON config above to:

  • Cursor: ~/.cursor/mcp.json
  • Windsurf: ~/.codeium/windsurf/mcp_config.json
  • VS Code (Copilot): .vscode/mcp.json in project root
OpenClaw / NemoClaw

OpenClaw has its own CLI — the JSON config above is not needed.

openclaw mcp add pop-pay -- npx -y pop-pay launch-mcp

Or add to ~/.openclaw/mcp_servers.json using the JSON config above.

For System Prompt templates and NemoClaw sandbox setup, see Integration Guide §4.

Docker
docker-compose up -d

Runs the MCP server + headless Chromium with CDP. Mount your encrypted vault from the host.

3. Launch Chrome with CDP and start using

npx -y pop-pay launch

Restart your MCP client. The agent now has access to pop-pay's MCP tools.

MCP Tools

ToolDescription
request_virtual_cardIssue a virtual card and inject credentials into the checkout page via CDP.
request_purchaser_infoAuto-fill billing/contact info (name, address, email, phone).
request_x402_paymentPay for API calls via the x402 HTTP payment protocol.
page_snapshotScan a checkout page for hidden prompt injections or anomalies.

Tip for Claude Code users: Add the following to your project's CLAUDE.md to help the agent know when to call pop-pay: "When you encounter a payment form or checkout page, use the request_virtual_card tool. For billing/contact info forms, use request_purchaser_info first."

Configuration

Core variables in ~/.config/pop-pay/.env. See ENV_REFERENCE.md for the full list.

VariableDefaultDescription
POP_ALLOWED_CATEGORIES["aws","cloudflare"]Approved vendor categories — see Categories Cookbook
POP_MAX_PER_TX100.0Max USD per transaction
POP_MAX_DAILY500.0Max USD per day
POP_BLOCK_LOOPStrueBlock hallucination/retry loops
POP_AUTO_INJECTtrueEnable CDP card injection
POP_GUARDRAIL_ENGINEkeywordkeyword (zero-cost) or llm (semantic)

Guardrail Mode

keyword (default)llm
MechanismKeyword matching on reasoning stringSemantic analysis via LLM
CostZero — no API callsOne LLM call per request
Best forDevelopment, low-risk workflowsProduction, high-value transactions

To enable LLM mode, see Integration Guide §1.

Providers

ProviderDescription
BYOC (default)Bring Your Own Card — encrypted vault credentials, local CDP injection.
Stripe IssuingReal virtual cards via Stripe API. Requires POP_STRIPE_KEY.
LithicMulti-issuer adapter (Stripe Issuing / Lithic).
MockTest mode with generated card numbers for development.

Priority: Stripe Issuing → BYOC Local → Mock.

Security

LayerDefense
Context IsolationCard credentials never enter the agent's context window or logs
Encrypted VaultAES-256-GCM with XOR-split salt and native scrypt key derivation (Rust)
TOCTOU GuardDomain verified at the moment of CDP injection — blocks redirect attacks
Repr RedactionAutomatic masking (****-4242) in all MCP responses, logs, and tracebacks

See THREAT_MODEL.md for the full STRIDE analysis and COMPLIANCE_FAQ.md for enterprise details.

Architecture

  • TypeScript — MCP server, CDP injection engine, guardrails, CLI
  • Rust (napi-rs) — Native security layer: XOR-split salt storage, scrypt key derivation
  • Node.js crypto — AES-256-GCM vault encryption (OpenSSL binding)
  • Chrome DevTools Protocol — Direct DOM injection via raw WebSocket

Documentation

License

MIT

Reviews

No reviews yet

Sign in to write a review