agent-payment-x402

Execute programmatic payments via x402 negotiation with ERC-4337 smart accounts.

1|Updated Apr 7, 2026
One-click install
npx skills add https://github.com/riftzen-bit/gemini-setup --skill agent-payment-x402-riftzen-bit
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: agent-payment-x402
Source: https://github.com/riftzen-bit/gemini-setup/tree/main/skills/agent-payment-x402
Command: npx skills add https://github.com/riftzen-bit/gemini-setup --skill agent-payment-x402-riftzen-bit

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Enable automated agents to perform paid actions without manual intervention while preventing runaway spend, custodial risk, and opaque transaction trails.

Core Features & Use Cases

  • x402 payment negotiation: Automatically handle HTTP 402 responses, negotiate price, sign transactions, and retry on success.
  • Spending controls: Enforce per-task and per-session budgets, allowlisted recipients, and rate limits to prevent overspend.
  • Non-custodial wallets: Use ERC-4337 smart accounts so agents hold keys locally while orchestration layers set strict policies.
  • MCP integration & auditability: Expose MCP tools (get_balance, send_payment, check_spending, list_transactions) for programmatic checks and post-task audits.
  • Use Case: Let an orchestrator safely delegate a paid API call to an agent while guaranteeing the call cannot exceed predefined budgets.

Quick Start

Set a SpendingPolicy in your orchestrator and instruct the agent to execute a single paid API call to api.example.com under a $0.01 per-task limit.

Frequently Asked Questions about agent-payment-x402

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I enable autonomous payments for AI agents without custodial wallet risk?▼

Enable autonomous agent payments safely by using ERC-4337 smart accounts for non-custodial wallet management, allowing agents to hold keys locally while orchestration layers enforce strict spending policies.

How does HTTP 402 payment negotiation work for automated agents?▼

HTTP 402 payment negotiation works by having the agent automatically handle 402 responses, negotiate the price, sign the transaction, and retry the original request upon successful payment.

How do I prevent runaway spending when agents execute programmatic payments?▼

Prevent runaway programmatic spending by defining a SpendingPolicy in your orchestrator to enforce per-task budgets, per-session limits, allowlisted recipients, and rate limits.

Can I audit agent transactions after executing paid API calls?▼

You can audit agent transactions using exposed MCP tools like list_transactions and check_spending, which provide programmatic checks and post-task auditability for signed actions.

Does this agent payment system work with ERC-4337 smart accounts?▼

Yes, the system uses ERC-4337 smart accounts for key handling, ensuring that agents execute signed, auditable transactions with non-custodial wallet management and fail-closed behavior.

What are the limitations of using non-custodial wallets for agent payments?▼

The fail-closed behavior of non-custodial agent payments means transactions will halt if predefined spending policies, budgets, or allowlisted recipient checks are violated.