steward mcp

Managing payments between AI agents and services is currently manual and friction-heavy. This skill enables agents to autonomously browse catalogs, get quotes, and execute pay-per-call transactions using the x402 protocol.

What it does

• x402 payment core handles the full transaction lifecycle including fetching quotes, verifying signatures, and submitting signed payments.
• Product discovery allows agents to browse the product catalog and retrieve specific purchase instructions.
• Spend tracking provides a local spend meter tool for agents to monitor their session expenditures against defined caps.
• Rewards integration fetches information on loyalty tiers and standard 10-15% reward rates.

How it works

1. The agent uses discovery tools to find products or services in the catalog.
2. It requests a quote for a specific action to receive the x402 payment requirements.
3. The user or wallet signs the transaction based on the quote provided.
4. The agent submits the signed proof to finalize the payment and access the service.

Frameworks & tools

This skill uses the Model Context Protocol (MCP) over stdio and targets USDC transactions on the Base network. It is built for Node.js environments.

Why this beats prompting it yourself

Writing manual logic for the x402 quote-verify-sign flow is error-prone and risks session timeouts or lost payments. This skill encapsulates the entire state machine, ensuring agents track their own spending and follow the protocol specifications exactly.

Use cases

• Automate micro-payments for agent-to-agent service calls.
• Track daily spending limits for autonomous agents.
• Verify payment signatures before fulfilling digital orders.
• Browse and buy digital assets through the x402 economy.

Known limitations

Transactions are limited to USDC on the Base network. Requires a Node.js runtime version 20 or higher and an MCP-compatible client.