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.
npx skills add Starchild-ai-agent/official-skills --skill x402git clone --depth 1 https://github.com/Starchild-ai-agent/official-skillsWrote 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.
[](https://agentmods.dev/skills/starchild-ai-agent/official-skills/x402)<a href="https://agentmods.dev/skills/starchild-ai-agent/official-skills/x402"><img src="https://agentmods.dev/badge/skills/starchild-ai-agent/official-skills/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.
<a href="https://agentmods.dev/skills/starchild-ai-agent/official-skills/x402"><img src="https://agentmods.dev/badge/skills/starchild-ai-agent/official-skills/x402.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Socket warn
- Snyk warn
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00125 | $0.08449 |
| Opus 5 | $0.00063 | $0.04224 |
| Sonnet 5 | $0.00025 | $0.01690 |
| Haiku 4.5 | $0.00013 | $0.00845 |
Grade A, and why
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 7d 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.
The source is not reproduced here
No licence file
A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.
What ships with it
30 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.
- bazaar.py 28 KB runs code
- client.py 75 KB runs code
- gateway/app.py 29 KB runs code
- gateway/ledger.py 8.0 KB runs code
- gateway/platform_modes.py 43 KB runs code
- logo.png 2.3 KB
- references/buying-advanced.md 5.2 KB
- references/selling.md 27 KB
- references/troubleshooting.md 15 KB
- scripts/buy.py 8.5 KB runs code
- scripts/discover.py 1.6 KB runs code
- scripts/ensure_env.sh 2.0 KB runs code
- scripts/keepalive.sh 2.9 KB runs code
- scripts/make_public.py 5.8 KB runs code
- scripts/monetize.py 19 KB runs code
- scripts/preflight.py 1.8 KB runs code
- scripts/verify_setup.py 14 KB runs code
- setup.sh 309 B runs code
- templates/lifetime.json 345 B
- templates/metered.json 693 B
- templates/monthly.json 343 B
- templates/multi_plan.json 549 B
- templates/pay_per_use.json 351 B
- templates/payperuse.json 768 B
- templates/prepaid.json 373 B
- templates/quarterly.json 435 B
- templates/subscription.json 651 B
- templates/timepass.json 645 B
- templates/weekly.json 431 B
- templates/yearly.json 432 B
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.
- 7d ago First seen · 568 lines · 125 tokens per session scan A 1417ab8c19d5
x402 is a skill published in the GitHub repository Starchild-ai-agent/official-skills (26 stars, last pushed today), with no licence file. It adds 125 tokens to every session and 8,449 once invoked, about $0.0006 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.
Other skills, from other repositories
alien-plugg-x402
38 paid x402 API endpoints for AI agents — Zora crypto analysis, Robinhood Chain tokenized stocks, on-chain intelligence, whale tracking, and utilities. MCP-compatible. Flat $0.003/call via USDC micropayments on Base.
gentech-x402-services
GenTech Labs paid API gateway — 7 x402 pay-per-call services on Base USDC: token security, market data, agent discovery, DeFi LP analytics, wallet analysis, NFT search. Use when an agent needs token risk scoring, token prices, onchain agent discovery, LP/pool analytics, wallet portfolio data, or NFT collection search…
cardzero
CardZero — the first payment wallet built for AI agents. Create USDC wallets on Base L2, make payments, pay x402 paywalls, pay other agents, check balance, view transactions, and run A2A jobs with on-chain escrow (ERC-8183). Human owner sets spending rules via Dashboard; agent pays autonomously within limits. Use when…
starknet-mini-pay
Simple P2P payments on Starknet. Generate QR codes, payment links, invoices, and transfer ETH/STRK/USDC. Like Lightning, but native.
bankr-shopify
Shopify Admin & Storefront GraphQL APIs via curl, with Bankr-native bridges. Manage products, orders, customers, inventory, metafields, webhooks, and bulk ops, then wire merchant data to onchain primitives — store a Bankr-resolvable handle (ENS, Twitter, Farcaster, wallet) on each customer as a metafield, expose…
lienfi
Research and buy tokenized US tax lien certificates on LienFi (Base, USDC) — screen the live book by NET yield with no credential, then, once your operator has authorized your wallet in a browser, register and run the prepare → sign → confirm → submit → report purchase loop from the wallet you control. LienFi signs…