x402-payments

x402-payments is a skill for Claude Code, Codex from Gentech-Labs/genTech-agent-kit. It costs 45 tokens per session (615 once invoked), scanned A, original, MIT.

A guide for adding payment requirements to web APIs used by AI agents. x402 is a web payment standard in which a server returns “402 Payment Required,” the agent pays through a facilitator, and then retries the request.

In plain words
What is it for?
Use it to build payment-gated endpoints and connect them to facilitators and networks such as Algorand, Robinhood Chain, and Base.
Why use it?
It explains how an API can request, verify, and settle payment before returning data, including how to manage payment sessions across supported networks.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: positional $N argument.

Good fit Use it to build payment-gated endpoints and connect them to facilitators and networks such as Algorand, Robinhood Chain, and Base.

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Install with agentmods
npx agentmods add skills/gentech-labs/gentech-agent-kit/x402-payments
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 Gentech-Labs/genTech-agent-kit --skill x402-payments
Clone the repo
git clone --depth 1 https://github.com/Gentech-Labs/genTech-agent-kit

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-payments

README.md
[![agentmods](https://agentmods.dev/badge/skills/gentech-labs/gentech-agent-kit/x402-payments/github.svg)](https://agentmods.dev/skills/gentech-labs/gentech-agent-kit/x402-payments)
Your own site
<a href="https://agentmods.dev/skills/gentech-labs/gentech-agent-kit/x402-payments"><img src="https://agentmods.dev/badge/skills/gentech-labs/gentech-agent-kit/x402-payments/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-payments

Your own site · 80×15
<a href="https://agentmods.dev/skills/gentech-labs/gentech-agent-kit/x402-payments"><img src="https://agentmods.dev/badge/skills/gentech-labs/gentech-agent-kit/x402-payments.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 45 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 615 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.
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 $0.00045 $0.00615
Opus 5 $0.00023 $0.00308
Sonnet 5 $0.00009 $0.00123
Haiku 4.5 $0.00005 $0.00061

Measured 8d ago against content hash 5fadb571e75b, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

x402-payments 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 8d 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.

skills/x402-payments/SKILL.md · 68 lines

How it starts

The opening of the file, as written. The whole thing — 68 lines — stays where its author put it; the contents beside it link to each section on GitHub.

x402 Payments for AI Agents

x402 is the HTTP-native payment standard. When an agent hits an endpoint without payment, the server returns 402 Payment Required with a challenge. The agent signs the payment and retries. The server verifies and serves the resource.

Payment Flow

Agent                    Server                   Facilitator
  │                        │                          │
  ├── GET /api/data ──────►│                          │
  │◄── 402 Payment ───────┤                          │
  │     Required           │                          │
  │                        │                          │
  ├── POST /facilitator/verify ──────────────────────►│
  │◄── Verified + Receipt ───────────────────────────┤
  │                        │                          │
  ├── GET /api/data ──────►│                          │
  │     (x402 header)      │                          │
  │◄── 200 OK + Data ─────┤                          │

Supported Networks

Network Facilitator Token Chain ID
Algorand GoPlausible ALGO algorand:localnet
Robinhood Chain Naven Network USDG eip155:4663
Base CDP Facilitator USDC eip155:8453

GenTech Kit Tools

from gentech_agent_kit.plugins.algorand_x402 import register_gentech_plugin
from gentech_agent_kit.plugins.robinhood_x402 import register_gentech_plugin

Tools auto-discovered. No manual config needed.

Session Management

Payments open a 60-minute session. Session token (HMAC-signed) is passed on subsequent calls:

session = algorand_verify_payment(payment_proof)
# session_token = "agent_1234567890_abc123:1712345678:signature"
data = algorand_get_quote("BTC", session_token=session_token)

Pricing Patterns

Pattern Use Case Example
Exact Fixed price per call $0.001 USDG per quote
Tiered Different prices for different data $0.001 crypto, $0.005 stocks
Subscription Batch pricing, session-based 10 queries for $0.01

Read the full file on GitHub · 68 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. 8d ago First seen · 68 lines · 45 tokens per session scan A 5fadb571e75b

Subscribe to this mod's changes

x402-payments is a skill published in the GitHub repository Gentech-Labs/genTech-agent-kit (0 stars, last pushed 17d ago), licensed MIT. It adds 45 tokens to every session and 615 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 2026-08-31.

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