# Z-ZERO

> The payment bridge between AI agents and the real economy. Agents pay 20,000+ merchants on the card-only web with USDC on Base — no merchant integration, human authorization built in, no PII. Agents never see real card numbers: payments use single-use JIT virtual cards or gasless USDC on Base.

Z-ZERO exposes payment capability to agents via its MCP server (npm: `z-zero-mcp-server`). Auth uses a Passport Key (`zk_live_...`) created by a human at the dashboard (max 3 active keys per account). Keys rotate on connect (v1.5.0+): a key pasted into a conversation dies seconds after first use — the live key is stored only on the agent's machine (`~/.z-zero/credentials`) and never exists in any LLM context. One key = one machine; a connect from a second machine disconnects the first. Proof of life: real purchase on Base mainnet, tx 0xdfd1f2f824e1232c3e03c52485332570ff01fbb0340c5571f699ed1218735d7a.

## Docs

- [Agent Guide (AGENT.md)](https://www.clawcard.store/agent.md): Full agent-facing README — site map, MCP install, API, error codes, SOP summary. Also served at `/` via content negotiation (Accept: text/markdown or AI user-agent).
- [Docs index](https://www.clawcard.store/docs): The human entry point to all four documents; each is listed individually below.
- [MCP Setup Guide](https://www.clawcard.store/docs/agent): Step-by-step install for Claude Desktop, Cursor, and other MCP clients.
- [Payment SOP v2.0](https://www.clawcard.store/docs/agent/skill): Standard Operating Procedure — read before your first purchase. `/docs/sop` is a legacy alias that redirects here; v2.0 is the only published SOP.
- [Checkout Intelligence Layer](https://www.clawcard.store/docs/agent/checkoutform): The 20+ checkout patterns the payment bridge handles, plus the live hint knowledge base behind `get_merchant_hints`.
- [API Reference](https://www.clawcard.store/docs/api): REST endpoints, Bearer auth, error codes.
- [Whitebook](https://www.clawcard.store/whitebook.md): Vision, why-now evidence, architecture, security model and roadmap — deep background for humans and agents evaluating Z-ZERO (not required to transact). Markdown; the same content is negotiated at /whitebook.

## Install

- [install-mcp.sh](https://www.clawcard.store/install-mcp.sh): macOS/Linux one-liner: `curl -sSL https://www.clawcard.store/install-mcp.sh | bash`
- [install-mcp.ps1](https://www.clawcard.store/install-mcp.ps1): Windows PowerShell: `iex (iwr https://www.clawcard.store/install-mcp.ps1).Content`
- [npm package](https://www.npmjs.com/package/z-zero-mcp-server): `npx -y z-zero-mcp-server@latest`

## Standards

- [A2A Agent Card](https://www.clawcard.store/.well-known/agent.json): Capability descriptor for agent-to-agent discovery.
- [llms-full.txt](https://www.clawcard.store/llms-full.txt): Full expanded corpus (guide + complete SOP) in one file.

## Optional

- [Dashboard](https://www.clawcard.store/login): Human dashboard — create Passport Keys, top up balance, set limits.
- [Proof on Basescan](https://basescan.org/tx/0xdfd1f2f824e1232c3e03c52485332570ff01fbb0340c5571f699ed1218735d7a): On-chain receipt of a real agent purchase.