x402-pay

x402-pay is a skill for Claude Code, Codex from runxhq/runx. It costs 21 tokens per session (378 once invoked), scanned A, original, Apache-2.0.

A payment tool for one x402-protected web resource, where x402 is a protocol that asks a client to pay before receiving an HTTP resource. It submits the payment and reads back the payment and resource result.

In plain words
What is it for?
It is for paying one named HTTPS resource through Runx Hosted and verifying that the payment became durable and the resource was received.
Why use it?
It handles the approval, payment signing, settlement recovery, and confirmation needed when an online resource requires payment.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit It is for paying one named HTTPS resource through Runx Hosted and verifying that the payment became durable and the resource was received.

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Install with agentmods
npx agentmods add skills/runxhq/runx/x402-pay
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 runxhq/runx --skill x402-pay
Clone the repo
git clone --depth 1 https://github.com/runxhq/runx

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 x402-pay

README.md
[![agentmods](https://agentmods.dev/badge/skills/runxhq/runx/x402-pay/github.svg)](https://agentmods.dev/skills/runxhq/runx/x402-pay)
Your own site
<a href="https://agentmods.dev/skills/runxhq/runx/x402-pay"><img src="https://agentmods.dev/badge/skills/runxhq/runx/x402-pay/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 x402-pay

Your own site · 80×15
<a href="https://agentmods.dev/skills/runxhq/runx/x402-pay"><img src="https://agentmods.dev/badge/skills/runxhq/runx/x402-pay.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 21 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 378 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 pass 7 Sept 2026
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 $0.00021 $0.00378
Opus 5 $0.00010 $0.00189
Sonnet 5 $0.00004 $0.00076
Haiku 4.5 $0.00002 $0.00038

Measured 9d ago against content hash 8fa61bfd7235, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

x402-pay 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.

The scan reads SKILL.md. This mod also ships 2 executable files (readback.mjs, readback.test.mjs), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

skills/x402-pay/SKILL.md · 38 lines

What it actually says

X402 Pay

x402-pay is the public x402 buyer contract. settle submits the exact payment signal once, and readback performs one observation of that durable payment and resource. The default pay runner composes both and requires immediate terminal readback, while durable callers compose settle once and re-enter readback through Runx's external-job scheduler.

Runx Hosted owns challenge validation, authority attenuation and reservation, wallet or facilitator credentials, payload signing, settlement recovery, finality, and the private ledger. The connector never sleeps or polls; durable continuation cadence belongs to Runx scheduling. OSS contains the public v1 Runx contract and generic provider-effect gate only. References to x402 protocol version 2 in upstream conformance material describe the external standard, not a Runx v2 contract.

Operator guide

Use this skill for one exact HTTPS resource already named by a hosted x402 grant. The resource request carries bounded inline control data or artifact references; large documents and media never travel as oversized graph values. The hosted buyer accepts external x402 V2 only, signs and stages the payload before the paid POST, and reuses those exact bytes after an uncertain response.

Stop on malformed or expired requirements, amount/currency/payee/resource drift, incomplete authority, missing approval, or inconsistent paid-resource readback. Never pass wallet keys, seed phrases, bearer tokens, or facilitator credentials in skill input. A 2xx response is not finality: the readback must return the provider transaction, confirmed chain block, and the paid resource's terminal Runx receipt reference.

Files

What ships with it

4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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 · 38 lines · 21 tokens per session scan A 8fa61bfd7235

Subscribe to this mod's changes

x402-pay is a skill published in the GitHub repository runxhq/runx (87 stars, last pushed 3d ago), licensed Apache-2.0. It adds 21 tokens to every session and 378 once invoked, about $0.0001 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 2026-09-03.