mpp-agent

mpp-agent is a skill for Claude Code, Codex from NousResearch/hermes-agent. It costs 16 tokens per session (1,320 once invoked), scanned C, original, MIT.

A client for the Machine Payments Protocol, a system for paying APIs per request. It is used when an API responds with HTTP 402 Payment Required and provides payment instructions.

In plain words
What is it for?
Paying per-request APIs, setting up an agent wallet, discovering MPP-priced services, and attaching a Stripe payment token to an API request.
Why use it?
It lets an agent access paid APIs through supported wallets or payment methods instead of treating the payment response as an error.

Skill for Claude CodeCodex

About the project

Hermes Agent is an AI assistant that learns from its use by creating and improving skills, retaining knowledge, searching past conversations, and adapting to its users. It is for people who want to run an agent through a terminal or messaging platforms while connecting it to different AI models and scheduled tasks.

NousResearch/hermes-agent · 241,505 stars · on GitHub · hermes-agent.nousresearch.com

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/nousresearch/hermes-agent/mpp-agent
Any agent
npx skills add NousResearch/hermes-agent --skill mpp-agent
Clone the repo
git clone --depth 1 https://github.com/NousResearch/hermes-agent

Made for: Claude Code, Codex.

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 mpp-agent

README.md
[![agentmods](https://agentmods.dev/badge/skills/nousresearch/hermes-agent/mpp-agent.svg)](https://agentmods.dev/skills/nousresearch/hermes-agent/mpp-agent)
Your own site
<a href="https://agentmods.dev/skills/nousresearch/hermes-agent/mpp-agent"><img src="https://agentmods.dev/badge/skills/nousresearch/hermes-agent/mpp-agent.svg" alt="Measured on agentmods" height="20"></a>
Per session 16 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,320 The whole file, excluding the scripts and references it only reads on demand.
Security scan C 2 findings. Scan, not verified.
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 $0.00016 $0.01320
Opus 5 $0.00008 $0.00660
Sonnet 5 $0.00003 $0.00264
Haiku 4.5 $0.00002 $0.00132

Measured 2d ago against content hash f44db1c9d2d0, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade C, and why

mpp-agent scanned grade C with 2 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 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.

Tells the agent never to refusehighAnti-refusal

Suppressing the ability to decline removes a core safety control; a later harmful request then succeeds.

- **Zero-amount challenges.** Some MPP endpoints charge `$0.00` and just want a proof credential. These work without a funded wallet. Don't refuse them as "broken."

Makes network callslowCapability

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

curl -i <url>
Origin

Copies of this mod

5 near-identical copies found in the catalogue:

optional-skills/payments/mpp-agent/SKILL.md · 125 lines

How it starts

The opening of the file, as written. The whole thing — 125 lines — stays where its author put it; the contents beside it link to each section on GitHub.

MPP Agent Skill

Wraps the Machine Payments Protocol (MPP, https://mpp.dev) clients so Hermes can pay for per-request API access against servers that respond with HTTP 402 Payment Required.

Three client options, all distributed via npm. Pick the lightest one that solves the user's need. Gated [linux, macos] while the broader payments tooling matures on Windows.

When to Use

  • A merchant API returns HTTP 402 with a www-authenticate header — and the user wants to actually pay it, not just log the response.
  • The user asks to "pay per request", "set up an agent wallet", "use Tempo / Privy / AgentCash", or wants to discover MPP-priced services.
  • A Stripe Link spend has produced a Shared Payment Token (SPT) and the agent needs to attach it to the 402 challenge — in that flow, prefer link-cli mpp pay (see the stripe-link-cli skill).

Choosing a client

Tool When Setup
link-cli User already has Stripe Link set up, or the 402 challenge advertises method="stripe" see the stripe-link-cli skill
Tempo Wallet MPP services with spend controls, service discovery tempo wallet login
Privy Agent CLI Multi-chain wallets, browser-based funding privy-agent-wallets login
AgentCash 300+ pre-priced APIs via one USDC.e balance npx agentcash onboard
mppx Dev + debugging, smallest dep surface npm install -g mppx then mppx account create

Default: if the user already has Stripe Link configured or the 402 challenge specifies method="stripe", use link-cli mpp pay (the stripe-link-cli skill). Otherwise mppx for one-off paid calls and debugging, and Tempo Wallet when the user wants persistent spend controls.

Prerequisites

  • Node.js 20+ on PATH
  • A funded wallet (Tempo / Privy / AgentCash) OR an mppx account
  • For Tempo / Privy / AgentCash: follow their respective onboarding skills:
    • https://tempo.xyz/SKILL.md
    • https://agents.privy.io/skill.md
    • https://agentcash.dev/skill.md

Read the full file on GitHub · 125 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. 2d ago First seen · 125 lines · 16 tokens per session scan C f44db1c9d2d0

Subscribe to this mod's changes

mpp-agent is a skill published in the GitHub repository NousResearch/hermes-agent (241,505 stars, last pushed today), licensed MIT. It adds 16 tokens to every session and 1,320 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it C with 2 findings (tells the agent never to refuse, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

Related

Other skills, from other repositories

portfolio

Cross-chain DeFi portfolio discovery, rebalancing suggestions, and NEAR Intent construction. Activates when the user pastes a wallet address or asks about yield/positions/rebalancing. Bootstraps a per-user "portfolio" project, aggregates positions across all the user's addresses inside one project, and offers a…

suyoumo/ClawProBench · 69 tokens

surf

Use when the user wants crypto data — token prices, on-chain SQL, prediction-market positions, CEX order books, wallet labels/net-worth, social mindshare, news, or unified search. 83 endpoints across exchange, on-chain, wallet, social, prediction, news and search — one API, flat $0.0085/call in USDC via x402. Settles…

BlockRunAI/blockrun-mcp · 92 tokens

crypto-data

Use for any crypto data question — token/coin prices, FX, commodities, stocks, OHLC history, DEX pairs and liquidity, DeFi TVL, yield/APY pools, on-chain SQL, wallet labels and net worth, social mindshare, news, or raw JSON-RPC against a chain. Routes across five tools that overlap heavily, so it also says which one…

BlockRunAI/blockrun-mcp · 170 tokens

polymarket-trading

Use when the user wants to actually PLACE, manage, or redeem bets on Polymarket (not just read odds — that's blockrunmarkets). Covers setup (deposit wallet, funding, approvals), buy/sell with confirm gating, positions, redeeming winnings, geoblock handling, and the end-to-end demo flow.

BlockRunAI/blockrun-mcp · 72 tokens

crypto-report

Get cryptocurrency market data. Get Binance AI analysis report. Get blockchain news updates.

aahl/skills · 19 tokens

x402

HTTP 402 payment protocol for AI agent commerce — three-actor model (Client, Resource Server, Facilitator), ERC-3009 transferWithAuthorization, server middleware (@x402/express), client patterns in TypeScript and Python, facilitator integration, agent-to-agent payments, pricing strategies, and replay protection. Works…

aomi-labs/skills · 84 tokens