cardzero

A payment wallet for AI agents that uses USDC, a digital dollar token, on Base, an Ethereum layer-2 network.

In plain words
What is it for?
Creating wallets, checking balances and transactions, paying x402 paywalls or other agents, and running A2A jobs with on-chain escrow.
Why use it?
It lets an agent make payments and run paid jobs within spending rules set by its human owner.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/mrocker/cardzero/openclaw
Any agent
npx skills add mrocker/CardZero --skill openclaw
Clone the repo
git clone --depth 1 https://github.com/mrocker/CardZero

Made for: Claude Code, Codex.

Per session 163 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,423 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
Origin unknown 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 $0.00163 $0.04423
Opus 5 $0.00081 $0.02211
Sonnet 5 $0.00033 $0.00885
Haiku 4.5 $0.00016 $0.00442

Measured 2d ago against content hash 588c398b6da6, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

cardzero scanned grade A with 1 finding 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 2d 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

- curl
plugins/openclaw/SKILL.md · 459 lines

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.

Read it on GitHub

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. 2d ago First seen · 459 lines · 163 tokens per session scan A 588c398b6da6

Subscribe to this mod's changes

cardzero is a skill published in the GitHub repository mrocker/CardZero (4 stars, last pushed 3mo ago), with no licence file. It adds 163 tokens to every session and 4,423 once invoked, about $0.0008 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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