x402-agent-payments-guide SKILL.md skillA
x402-agent-payments-guide from nirholas/three.ws is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add nirholas/three.ws/x402-agent-payments-guide@git:20260501.87cefc9Pins git:20260501.87cefc9 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- nirholas/three.ws
- Path
data/skills/protocol/x402-agent-payments-guide/SKILL.md- Versions recorded
- 1
- Latest version
- git:20260501.87cefc9, committed May 1, 2026
- Size
- 4,595 bytes
- Repository stars
- 269
- License
- Apache-2.0
Guide to the x402 protocol — HTTP-native micropayments for AI agents. Enables agents to pay for API calls, data, and services using stablecoins (USDC, USDs) without API keys or subscriptions. Built on EIP-712 signed payment headers.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# x402 Agent Payments Guide
x402 is the HTTP-native micropayment protocol for AI agents. It enables agents to pay for API calls, data, and services using stablecoins — no API keys, no subscriptions, just a signed payment header.
## How x402 Works
```
Agent → HTTP Request + x402 Payment Header → Server
│
Verify Payment
│
✅ Valid → Serve Content
❌ Invalid → 402 Payment Required
```
### The Flow
1. Agent makes HTTP request to a paid endpoint
2. Server returns `402 Payment Required` with pricing info
3. Agent signs an EIP-712 payment authorization
4. Agent retries with `X-402-Payment` header
5. Server verifies signature and serves content
6. Payment settles on-chain (batched for efficiency)
## Payment Header
```http
X-402-Payment: {
"version": "1",
"sender": "0xAgentAddress",
"amount": "0.001",
"token": "USDs",
"chain": "arbitrum",
"signature": "0x...",
"nonce": 42,
"expiry": 1735689600
}
```
## Supported Tokens
…Read the whole file at its exact version.
How to install
mdr add nirholas/three.ws/x402-agent-payments-guide@sha256:e0424ebb464c4966The line at the top of this page pins the label git:20260501.87cefc9, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_gklcb5rfgg3unbrp)
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Versions
The registry has recorded 1 version of this file, committed on May 1, 2026.
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (4595 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
nirholas/three.ws · 269 stars · license Apache-2.0 · pushed 2026-11-06 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_gklcb5rfgg3unbrp GET https://markdownregistry.com/api/v1/resolve?ref=nirholas/three.ws/x402-agent-payments-guide GET https://markdownregistry.com/api/v1/blob/e0424ebb464c4966245f363d5134c7a1fa4f7af974552e0ed44f83c0eeb4830f
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.