ProofPay

ProofPay is a custody-minimized paid-delivery primitive for ZeroClaw. An agent can create a Solana Pay invoice, verify an exact finalized SPL-token payment, and release an AES-256-GCM sealed artifact.

The model never receives encryption keys and cannot choose the recipient, mint, RPC, file roots, token decimals, or amount ceiling. Those remain operator-owned TOML policy.

MCP surface

• proofpay__create_invoice(artifact_name, amount, buyer_label?)

• proofpay__invoice_status(invoice_id)

• proofpay__release_artifact(invoice_id) — writes the verified plaintext locally and returns paid UTF-8 content inline when it is within the operator cap.

Related MCP server: arbitova-mcp-server

Payment rule

A payment is accepted only when a finalized transaction includes the per-invoice reference and an exact configured-mint balance delta for the configured recipient. A reference touch, wrong mint, wrong recipient, underpayment, overpayment, failed transaction, or non-finalized transaction fails closed.

Quick start

python3.12 -m venv .venv
.venv/bin/pip install -e '.[dev]'
cp examples/proofpay.toml proofpay.local.toml
# Replace paths and recipient in proofpay.local.toml.
.venv/bin/proofpay-mcp --config proofpay.local.toml

Run the test suite:

.venv/bin/python -m pytest tests -q

The stdio integration test launches the actual MCP subprocess, initializes a client session, lists the three tools, and creates an invoice. The production-shaped ZeroClaw receipt is in docs/zeroclaw-v0.8.4-receipt.json; the labeled synthetic paid-release receipt is in docs/demo-receipt.json; the optional real-chain harness is documented in docs/DEVNET_SMOKE.md.

ZeroClaw

Install ZeroClaw, then merge examples/zeroclaw-config-snippet.toml into its config and grant the revenue MCP bundle only to the intended agent. Copy skills/proofpay/SKILL.md into that agent's skill bundle.

zeroclaw --version
zeroclaw --config-dir /path/to/config status

ProofPay has been exercised against ZeroClaw v0.8.4's current MCP schema. Absolute paths are intentional: the spawned stdio process must not depend on shell activation.

Architecture

buyer/channel -> ZeroClaw agent -> narrow MCP tools -> ProofPay policy
                                                    |-> Solana JSON-RPC
                                                    |-> SQLite invoice state
                                                    `-> AES-GCM sealed artifact

Security and scope

Read docs/THREAT_MODEL.md before deployment. This prototype handles invoice creation, exact payment verification, and local release. It does not provide buyer authentication, refunds, disputes, tax handling, sanctions screening, or encrypted buyer delivery.

License

MIT