Arbitrum Transaction Preflight

Name: Arbitrum Transaction Preflight
Author: naur9n

by naur9nversion 4.0.0i★ –iRuns on your computer

Registry nameio.github.naur9n/arbitrum-transaction-preflight

Install

Overview

Description from the maker (original English)

Paid Arbitrum transaction simulation and risk scoring for wallets and AI agents.

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

User voiceiNo reviews yetReviews open together with accounts in a later step
Our basic checksi1 of 1 passedChecked from public information; code not scanned yet
UsageiVery new↓ 33/wk · ★ –

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

Connection: Runs on your computer
Transport: stdio
Category: Other
You need to fill in: CLIENT_PRIVATE_KEY

Install

Pick the AI app you use, then copy the settings.

Before you install

Basic checks: 1 of 1 passed
Runs on your computer with your user’s permissions (files, network, apps).
You fill in yourself: CLIENT_PRIVATE_KEY, SERVER_URL, CHAIN_ID

Values marked secret are keys to your account. Never share them or paste them into a chat.

You need

npmNode.js installed (for the npx command)

Which app do you use?

ClaudeClaude CodeCursorVS CodeChatGPT

Pick your app above. We remember it, so next time the button says “Install in …”.

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

{
  "mcpServers": {
    "arbitrum-transaction-preflight": {
      "command": "npx",
      "args": [
        "-y",
        "arbitrum-mpp-transaction-preflight"
      ],
      "env": {
        "CLIENT_PRIVATE_KEY": "your-value",
        "SERVER_URL": "your-value",
        "CHAIN_ID": "your-value"
      }
    }
  }
}

Run this in your terminal

claude mcp add arbitrum-transaction-preflight --env CLIENT_PRIVATE_KEY=your-value --env SERVER_URL=your-value --env CHAIN_ID=your-value -- npx -y arbitrum-mpp-transaction-preflight

Fill in the empty values before running it.

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "arbitrum-transaction-preflight": {
      "command": "npx",
      "args": [
        "-y",
        "arbitrum-mpp-transaction-preflight"
      ],
      "env": {
        "CLIENT_PRIVATE_KEY": "your-value",
        "SERVER_URL": "your-value",
        "CHAIN_ID": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "arbitrum-transaction-preflight": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "arbitrum-mpp-transaction-preflight"
      ],
      "env": {
        "CLIENT_PRIVATE_KEY": "your-value",
        "SERVER_URL": "your-value",
        "CHAIN_ID": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.

Your choice stays on this device in a cookie; no account needed.

Values you fill in

CLIENT_PRIVATE_KEY secret required env
Dedicated low-value payer key.
SERVER_URL env
Hosted paid API base URL.
CHAIN_ID env
42161 for Arbitrum One.

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

Runs on your computer; the tool list appears in your AI app after you install it.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 8, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account naur9n, which owns the repo
… Not checked yet
Still maintained
We have not read this repo from GitHub yet
… Not checked yet
Has a licence
We have not read this repo from GitHub yet
– Not applicable
Endpoint responds
This one runs on your computer; there is no internet endpoint
– Not applicable
Sign-in with OAuth
Runs on your computer and uses local settings instead
… Not checked yet
No hidden instructions in tool descriptions
Runs on your computer; we can only read tool lists from internet endpoints

Compared with others in Otheri

More stars than 0% of the other 18594 servers in this category
Published to the registry more recently than 15% of the other 18594 servers in this category
Basic checks equal to or better than 100% of the other 18594 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is Arbitrum Transaction Preflight safe?

It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

You need to fill in: CLIENT_PRIVATE_KEY

Does it run on my computer or in the cloud?

It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).

Is it still maintained?

The GitHub repo last changed –, and the latest version (4.0.0) reached the registry 4 months ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Node.js on your computer.

What can I use instead?

In the same category: Spec Driven Development, Remote Desktop Commander, Commonly

Alternatives

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Install

README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

Arbitrum Transaction Preflight

Paid transaction simulation and risk reports for wallets, bots, and AI agents. Before a transaction is signed, the API checks whether it simulates successfully, estimates gas, detects token/NFT approvals, inspects the target, and returns a machine-readable risk score.

Production API: https://arbitrum-mpp-transaction-preflight-production.up.railway.app

Product and pricing

Network: Arbitrum One (42161)
Asset: native USDC (0xaf88d065e77c8cC2239327C5EDb3A432268e5831)
Launch price: 0.10 USDC per report (100000 raw USDC units)
Primary payment channel: MPP with EIP-3009
Optional distribution channel: x402 with Coinbase CDP/Bazaar
Agent interface: MCP stdio server that pays the MPP endpoint with the caller's wallet

The service never asks for a transaction-signing wallet. The example MPP/MCP clients use a separate low-value payer key only to authorize the API payment.

Discovery endpoints

The hosted service exposes free discovery metadata:

GET / — product, network, price, and endpoint summary
GET /health — health check
GET /openapi.json — MPP-aware OpenAPI 3.1 discovery document
GET /llms.txt — concise instructions for AI agents
GET /.well-known/agent.json — agent/service metadata

MPP clients call:

POST /v1/preflight

When x402 is enabled, x402 clients call:

POST /x402/v1/preflight

Request and report

"from": "0x0000000000000000000000000000000000000001", "to": "0x0000000000000000000000000000000000000002", "data": "0x", "valueEth": "0" }

from and to are required. data defaults to 0x. Use either valueEth or valueWei for native value. A successful paid response contains:

call simulation success/revert details;
gas estimate, gas price, and estimated ETH cost;
EOA/contract target inspection;
ERC-20 approve and NFT setApprovalForAll detection;
weighted risk score and warnings;
block number and check timestamp.

Automated simulation and heuristics reduce risk but are not a guarantee of safety.

Run locally

Requirements: Node.js 22+ and a dedicated server wallet. On mainnet, the server wallet needs a small Arbitrum One ETH balance for MPP settlement gas.

npm install

cp .env.example .env npm run server

Minimum production configuration:

SERVER_PRIVATE_KEY=0x...

CHAIN_ID=42161 ARBITRUM_RPC=https://arb1.arbitrum.io/rpc PRICE_RAW_USDC=100000 ENABLE_FREE_DEMO=false SERVER_URL=https://arbitrum-mpp-transaction-preflight-production.up.railway.app

Never commit .env or expose SERVER_PRIVATE_KEY.

MPP client

The included client performs the complete 402 -> authorization -> retry -> receipt flow:

CLIENT_PRIVATE_KEY=0x...

TARGET_ADDRESS=0x... SERVER_URL=https://arbitrum-mpp-transaction-preflight-production.up.railway.app CHAIN_ID=42161

npm run client

The payer needs native USDC on Arbitrum One. It does not need ETH for the MPP payment; the merchant settles the signed EIP-3009 authorization.

MCP integration

The MCP server exposes check_arbitrum_transaction. It uses the caller's dedicated CLIENT_PRIVATE_KEY to pay the hosted MPP API, so each tool call produces API revenue instead of bypassing payment.

npm run mcp

After the npm package is published, MCP hosts can run:

"mcpServers": { "arbitrum-preflight": { "command": "npx", "args": ["-y", "arbitrum-mpp-transaction-preflight"], "env": { "CLIENT_PRIVATE_KEY": "0x...", "SERVER_URL": "https://arbitrum-mpp-transaction-preflight-production.up.railway.app", "CHAIN_ID": "42161" } } } }

Use a dedicated low-value payer wallet. Never reuse a valuable wallet key.

Enable x402 and Bazaar

Production x402 settlement on Arbitrum uses Coinbase's CDP facilitator. Create a CDP project and add these Railway variables:

ENABLE_X402=true

CDP_API_KEY_ID=... CDP_API_KEY_SECRET=...

The server then exposes POST /x402/v1/preflight with Bazaar discovery metadata. MPP remains available at POST /v1/preflight; the two payment channels share the same analysis engine and merchant address.

Development checks

npm run typecheck

npm run build npm pack --dry-run

Set ENABLE_FREE_DEMO=true only for local development to expose POST /demo/preflight without payment. Never enable it in production.

Publishing surfaces

The repository includes server.json and npm metadata for the official MCP Registry. Release order:

deploy this version to Railway;
publish arbitrum-mpp-transaction-preflight to npm;
publish server.json with mcp-publisher;
enable CDP x402 to become eligible for Bazaar indexing;
submit the live MPP endpoint to the MPP services catalog.

Official Arbitrum MPP guide: https://docs.arbitrum.io/build-decentralized-apps/machine-payments-protocol

Arbitrum Transaction Preflight

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

Values you fill in

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Compared with others in Otheri

Common questions

Alternatives

Spec Driven Development

Remote Desktop Commander

Commonly

README from the maker

Arbitrum Transaction Preflight

Product and pricing

Discovery endpoints

Request and report

Run locally

MPP client

MCP integration

Enable x402 and Bazaar

Development checks

Publishing surfaces