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octodamus-core: Skill for Claude Code

.agents/skills/x402/SKILL.md

x402 is a skill for Claude Code from Octodamus/octodamus-core. It costs 69 tokens per session (1,351 once invoked), scanned A, original, MIT.

A tool for finding paid web services and calling their APIs through the x402 payment protocol, which handles payment as part of an API request. It uses USDC, a dollar-linked digital currency, on supported blockchain networks such as Base.

In plain words
What is it for?
Finding services in the x402 bazaar, checking their price, request method, and input format, and calling paid API endpoints. Searches can be narrowed by network, payment method, and maximum price.
Why use it?
It helps when you do not know which service or API to use and need to check its price and required inputs before paying. It also avoids handling the payment step separately when making a supported request.

Skill for Claude Code

Written for Claude Code: disable-model-invocation in frontmatter. Also seen: positional $N argument; installed under .agents/ (shared by several agents).

This is Octodamus/octodamus-core's own configuration. It tells Claude Code how to work on octodamus-core itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything octodamus-core configures →

not rated 2repo 27d ago A scan 69 tokens original MIT
View source ↗ Octodamus/octodamus-core
Reuse

Borrowing it

Nothing to install: this file belongs to Octodamus/octodamus-core. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/Octodamus/octodamus-core/main/.agents/skills/x402/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/Octodamus/octodamus-core

Made for: Claude Code.

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

README.md
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Your own site
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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

Your own site · 80×15
<a href="https://agentmods.dev/skills/octodamus/octodamus-core/x402"><img src="https://agentmods.dev/badge/skills/octodamus/octodamus-core/x402.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 69 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,351 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 $0.00069 $0.01351
Opus 5.5 $0.00028 $0.00540
Sonnet 5.5 $0.00014 $0.00270
Haiku 4.5 $0.00007 $0.00135

Measured 2mo ago against content hash 16a871b2c869, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

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 2mo 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.

.agents/skills/x402/SKILL.md · 131 lines

How it starts

The opening of the file, as written. The whole thing — 131 lines — stays where its author put it; the contents beside it link to each section on GitHub.

x402 Payment Protocol

Use the npx [email protected] x402 commands to discover, inspect, and call paid API endpoints using the X402 payment protocol. Payments are made in USDC on Base.

Workflow

The typical x402 workflow is:

  1. Find a service - Search the bazaar or get details for a known endpoint
  2. Check requirements - Inspect price, method, and input schema
  3. Make the request - Call the endpoint with automatic USDC payment

Commands

Search the Bazaar

Find paid services by keyword using BM25 relevance search:

npx [email protected] x402 bazaar search <query> [-k <n>] [--network <network>] [--scheme <scheme>] [--max-price <price>] [--json]
Option Description
-k, --top <n> Number of results, 1–20 (default: 20)
--network <name> Filter by chain (base, base-sepolia, polygon, solana, solana-devnet)
--scheme <scheme> Filter by payment scheme: exact or upto
--max-price <price> Maximum price in USD (e.g. 0.01)
--asset <address> Filter by payment asset address
--pay-to <address> Filter by recipient wallet address
--extensions <type> Filter by extension type (e.g. outputSchema, bazaar)
--json Output as JSON

List Bazaar Resources

Browse all available resources:

npx [email protected] x402 bazaar list [--network <network>] [--full] [--refresh] [--json]
Option Description
--network <name> Filter by chain (base, base-sepolia, polygon, solana, solana-devnet)
--full Show complete details including schemas
--refresh Re-fetch resource index from CDP API
--json Output as JSON

Read the full file on GitHub · 131 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. 2mo ago First seen · 131 lines · 69 tokens per session scan A 16a871b2c869

Subscribe to this mod's changes

x402 is a skill published in the GitHub repository Octodamus/octodamus-core (2 stars, last pushed 27d ago), licensed MIT. It adds 69 tokens to every session and 1,351 once invoked, about $0.0003 per session on Opus 5.5. 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.

Backend and APIsWeb3 and blockchain
Related

x402 compared with skills from other repositories

x402 next to 6 skills from other repositories
ModTypeStarsLast pushLicenceScanTokensWorks with
x402Octodamus/octodamus-coreSkill227d agoMITA69Claude Code
solana-devsolana-foundation/solana-dev-skillSkill5842d agoMITA258Claude Code, Codex
devtools-event-clientTanStack/devtoolsSkill510yesterdayMITA79Claude Code, Codex
walkeros-create-destinationelbwalker/walkerOSSkill3492d agoMITA77Claude Code
walkeros-create-sourceelbwalker/walkerOSSkill3492d agoMITA65Claude Code
web3-fullstack-packaged-buildHKUDS/OpenSpaceSkill7.8k2mo agoMITA21Claude Code, Codex
web3-fullstack-systematic-buildHKUDS/OpenSpaceSkill7.8k2mo agoMITA21Claude Code, Codex