agent-payment-x402

agent-payment-x402 is a skill for Claude Code, Codex from ufy2024/AuC. It costs 49 tokens per session (2,613 once invoked), scanned A, original, MIT.

A payment guide for AI agents using x402, an HTTP payment protocol, with non-custodial wallets and spending rules.

In plain words
What is it for?
Use it to connect payments on Base or X Layer, set task budgets, use agentwallet-sdk or OKX payment protocols, and build TypeScript or Go services that charge agents.
Why use it?
It lets agents pay for approved APIs, services, or other agents while limiting spending per task without holding funds in a custodial account.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions subagents; mentions Claude Code.

Good fit Use it to connect payments on Base or X Layer, set task budgets, use agentwallet-sdk or OKX payment protocols, and build TypeScript or Go services that charge agents.

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Install with agentmods
npx agentmods add skills/ufy2024/auc/agent-payment-x402
View source ↗ ufy2024/AuC
About the project

AuC is a Python framework for running a single AI agent with an asynchronous, pluggable reasoning loop, language-model adapters, permission levels, and observable events. It is used to build coding and conversational agents with tools, security checks, web interfaces, background jobs, evaluations, and isolated execution. The catalogue entries are skills for extending its agent workflow.

ufy2024/AuC · 1,090 stars · on GitHub

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add ufy2024/AuC --skill agent-payment-x402
Clone the repo
git clone --depth 1 https://github.com/ufy2024/AuC

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for agent-payment-x402

README.md
[![agentmods](https://agentmods.dev/badge/skills/ufy2024/auc/agent-payment-x402/github.svg)](https://agentmods.dev/skills/ufy2024/auc/agent-payment-x402)
Your own site
<a href="https://agentmods.dev/skills/ufy2024/auc/agent-payment-x402"><img src="https://agentmods.dev/badge/skills/ufy2024/auc/agent-payment-x402/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for agent-payment-x402

Your own site · 80×15
<a href="https://agentmods.dev/skills/ufy2024/auc/agent-payment-x402"><img src="https://agentmods.dev/badge/skills/ufy2024/auc/agent-payment-x402.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 49 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,613 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 4 findings, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Agent Snooping · line 21
    Skill enumerates or reads other installed skills. Access to other skills' SKILL.md files or the skills directory reveals prompt instructions, capabilities, and secrets that should be invisible to peer skills.
    Fix: Remove all code or instructions that list or read other skills' files or directories. Skills should operate independently; cross-skill access is a privilege escalation.
  • medium Agent Snooping · line 107
    Skill enumerates or reads other installed skills. Access to other skills' SKILL.md files or the skills directory reveals prompt instructions, capabilities, and secrets that should be invisible to peer skills.
    Fix: Remove all code or instructions that list or read other skills' files or directories. Skills should operate independently; cross-skill access is a privilege escalation.
  • medium Agent Snooping · line 108
    Skill enumerates or reads other installed skills. Access to other skills' SKILL.md files or the skills directory reveals prompt instructions, capabilities, and secrets that should be invisible to peer skills.
    Fix: Remove all code or instructions that list or read other skills' files or directories. Skills should operate independently; cross-skill access is a privilege escalation.
  • medium Excessive Agency · line 120
    Skill enables autonomous high-impact decisions without human-in-the-loop verification. Critical operations (destructive commands, financial transactions, data deletion) should require explicit user confirmation.
    Fix: Add human-in-the-loop confirmation for destructive, irreversible, or high-impact operations. Never auto-execute commands that modify files, send data, or alter system state.
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00049 $0.02613
Opus 5 $0.00024 $0.01307
Sonnet 5 $0.00010 $0.00523
Haiku 4.5 $0.00005 $0.00261

Measured 9d ago against content hash 12cf6fcf505c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

agent-payment-x402 scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 9d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

Copies of this mod

4 near-identical copies found in the catalogue:

auc/skill_library/bundled/agent-payment-x402/SKILL.md · 246 lines

How it starts

The opening of the file, as written. The whole thing — 246 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Agent Payment Execution (x402)

Enable AI agents to make policy-gated payments with built-in spending controls. Uses the x402 HTTP payment protocol and MCP tools so agents can pay for external services, APIs, or other agents without custodial risk.

When to Use

Use when: your agent needs to pay for an API call, purchase a service, settle with another agent, enforce per-task spending limits, or manage a non-custodial wallet. Pairs naturally with cost-aware-llm-pipeline and security-review skills.

Decision Tree

Choose the integration path based on whether your agent is buying access to a paid API or charging others for one:

Need Recommended path
Agent pays a 402-gated API on Base or another agentwallet-supported chain Use agentwallet-sdk as an MCP payment server with strict spending policy
Agent pays a 402-gated API on X Layer Use OKX Agent Payments Protocol from okx/onchainos-skills; okx-x402-payment is a deprecated legacy alias
TypeScript API charges agents Use OKX Payments TypeScript seller SDK docs for Express, Hono, Fastify, or Next.js
Go API charges agents Use OKX Payments Go seller SDK docs for Gin, Echo, or net/http
Rust API charges agents Use OKX Payments Rust seller SDK docs for Axum
Java API charges agents Use OKX Payments Java seller SDK docs for Spring Boot 2/3, Java EE, or Jakarta
Python API charges agents Check the current OKX Payments repository before implementation; a Python seller guide may not be available

Supported Networks

  • agentwallet-sdk: use the package docs to confirm current network coverage before production. Base Sepolia is the safest development default; Base mainnet is the production path called out by the original skill.
  • OKX Payments / X Layer: current seller docs target X Layer (eip155:196) and USDT0 settlement. Fetch current SDK docs before generating production code because payment packages and facilitator behavior can change quickly.

Read the full file on GitHub · 246 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 9d ago First seen · 246 lines · 49 tokens per session scan A 12cf6fcf505c

Subscribe to this mod's changes

agent-payment-x402 is a skill published in the GitHub repository ufy2024/AuC (1,090 stars, last pushed 1mo ago), licensed MIT. It adds 49 tokens to every session and 2,613 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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