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"
      }
    }
  }
}

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

Tool	Description
`request_virtual_card`	Issue a virtual card and inject credentials into the checkout page via CDP. Automatically scans the page for hidden prompt injections.
`request_purchaser_info`	Auto-fill billing/contact info (name, address, email, phone). Automatically scans the page for hidden prompt injections.
`request_x402_payment`	Pay for API calls via the x402 HTTP payment protocol.

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.

Variable	Default	Description
`POP_ALLOWED_CATEGORIES`	`["aws","cloudflare"]`	Approved vendor categories — see Categories Cookbook
`POP_MAX_PER_TX`	`100.0`	Max USD per transaction
`POP_MAX_DAILY`	`500.0`	Max USD per day
`POP_BLOCK_LOOPS`	`true`	Block hallucination/retry loops
`POP_AUTO_INJECT`	`true`	Enable CDP card injection
`POP_GUARDRAIL_ENGINE`	`keyword`	`keyword` (zero-cost) or `llm` (semantic)

Guardrail Mode

	`keyword` (default)	`llm`
Mechanism	Keyword matching on reasoning string	Semantic analysis via LLM
Cost	Zero — no API calls	One LLM call per request
Best for	Development, low-risk workflows	Production, high-value transactions

To enable LLM mode, see Integration Guide §1.

Providers

Provider	Description
BYOC (default)	Bring Your Own Card — encrypted vault credentials, local CDP injection.
Stripe Issuing	Real virtual cards via Stripe API. Requires `POP_STRIPE_KEY`.
Lithic	Multi-issuer adapter (Stripe Issuing / Lithic).
Mock	Test mode with generated card numbers for development.

Priority: Stripe Issuing → BYOC Local → Mock.

Security

Layer	Defense
Context Isolation	Card credentials never enter the agent's context window or logs
Encrypted Vault	AES-256-GCM with XOR-split salt and native scrypt key derivation (Rust)
TOCTOU Guard	Domain verified at the moment of CDP injection — blocks redirect attacks
Repr Redaction	Automatic 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

Threat Model — STRIDE analysis, 5 security primitives, 10 attack scenarios
Guardrail Benchmark — 95% accuracy across 20 test scenarios
Compliance FAQ — PCI DSS, SOC 2, GDPR details
Environment Reference — All POP_* environment variables
Integration Guide — Setup for Claude Code, Node.js SDK, and browser agents
Categories Cookbook — POP_ALLOWED_CATEGORIES patterns and examples

License

MIT

Point One Percent — pop-pay