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.
curl -O https://raw.githubusercontent.com/Octodamus/octodamus-core/main/.agents/skills/x402/SKILL.mdgit clone --depth 1 https://github.com/Octodamus/octodamus-coreWrote 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/octodamus/octodamus-core/x402)<a href="https://agentmods.dev/skills/octodamus/octodamus-core/x402"><img src="https://agentmods.dev/badge/skills/octodamus/octodamus-core/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/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>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 | $0.00069 | $0.01351 |
| Opus 5 | $0.00034 | $0.00675 |
| Sonnet 5 | $0.00014 | $0.00270 |
| Haiku 4.5 | $0.00007 | $0.00135 |
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 12d 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.
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:
- Find a service - Search the bazaar or get details for a known endpoint
- Check requirements - Inspect price, method, and input schema
- 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 |
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.
- 12d ago First seen · 131 lines · 69 tokens per session scan A 16a871b2c869
x402 is a skill published in the GitHub repository Octodamus/octodamus-core (1 stars, last pushed today), licensed MIT. It adds 69 tokens to every session and 1,351 once invoked, about $0.0003 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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