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Address Poisoning Check

Official registry Finance and payments

Before sending crypto, check the recipient for address poisoning: lookalikes and bad checksums

Source code Website Documentation

What can you do with Address Poisoning Check?

Install

Add this to your client's MCP configuration (Claude Desktop: claude_desktop_config.json; Cursor: .cursor/mcp.json; VS Code and others use the same "mcpServers" shape).

Remote (streamable-http)
Claude Code 
claude mcp add --transport http address-poisoning-check 'https://address-poisoning-check.nextill-pos.workers.dev/mcp'
JSON configuration (Claude Desktop, Cursor, VS Code) 
{
    "mcpServers": {
        "address-poisoning-check": {
            "type": "http",
            "url": "https://address-poisoning-check.nextill-pos.workers.dev/mcp"
        }
    }
}
NPM package devx-address-poisoning-check
Claude Code 
claude mcp add address-poisoning-check -- npx -y devx-address-poisoning-check@1.0.0 mcp
JSON configuration (Claude Desktop, Cursor, VS Code) 
{
    "mcpServers": {
        "address-poisoning-check": {
            "command": "npx",
            "args": [
                "-y",
                "devx-address-poisoning-check@1.0.0",
                "mcp"
            ]
        }
    }
}

Documentation

From the project's README on GitHub, refreshed weekly. Links open on GitHub.

Contents
  1. Address Poisoning Check
  2. CLI
  3. MCP
  4. Paid on-chain check (x402)
  5. Related DevX tools
  6. Layout

Address Poisoning Check

Is this the address you meant? Address poisoning plants a lookalike address (same first and last characters, different middle) in a wallet's history with a zero-value, dust or fake-token transfer, and waits for the owner (or their AI agent) to copy it. Bitquery counted about $76M stolen on Ethereum alone in the 12 months to July 2026.

This repo has three pieces, all read-only (we never ask for keys and never move funds):

WhatCost
CLI / stdio MCP devx-address-poisoning-checkOffline: is the recipient a lookalike of any address you trust? Is its EIP-55 checksum valid? Nothing leaves your machine.free
Remote MCP https://address-poisoning-check.nextill-pos.workers.dev/mcpSame offline check as a hosted MCP toolfree
HTTP API GET /v1/check?from=<sender>&to=<recipient>On-chain: scans the sender's real transfer history (Ethereum + Base, optional Avalanche) and flags lookalikes of real counterparties, zero-value / dust / fake-token poisoning transfers (with tx hashes), recipients that only ever appeared through such transfers, and senders that were already poisoned. Returns `ok \caution \danger` and the address you probably meant.0.005 USDC via x402 on Base

Live: https://address-poisoning-check.nextill-pos.workers.dev

CLI

npx devx-address-poisoning-check 0xd9A1C3788D81257612E2581A6ea0aDa244853a91 --known 0xd9A1b0B1e1aE382DbDc898Ea68012FfcB2853a91
# DANGER: Looks like 0xd9a1...3a91 (same first 4 / last 6 hex chars) but is a different address. Classic address-poisoning lookalike.

Exit code 2 on danger, so it can gate scripts and agent payment flows.

MCP

Claude Desktop / Cursor (stdio):

{ "mcpServers": { "address-poisoning-check": { "command": "npx", "args": ["-y", "devx-address-poisoning-check", "mcp"] } } }

Or remote (streamable HTTP): https://address-poisoning-check.nextill-pos.workers.dev/mcp

Tools: check_recipient_lookalike (free), onchain_check_info (how to buy the on-chain check; does not pay).

Paid on-chain check (x402)

GET https://address-poisoning-check.nextill-pos.workers.dev/v1/check?from=0x...&to=0x...[&chains=ethereum,base,avalanche]
  • Answers 402 with an x402 v1 body (X-PAYMENT, network base) and a v2 PAYMENT-REQUIRED header (PAYMENT-SIGNATURE, eip155:8453). Both work.
  • 5000 atomic USDC (0.005 USDC) to 0xB3cDDccEe6B150c8efFD55B961afc0Ecefe7f247, settled through the Coinbase CDP facilitator, listed in the CDP x402 Bazaar.
  • Settled only after the report is produced; bad input or data-source errors are not charged.
  • Data: Ethereum/Avalanche via the Routescan explorer API (last 300 token transfers + 150 transactions of the sender); Base via the Coinbase CDP SQL API (last 14 days of all ERC-20 transfers, including unknown/fake tokens), falling back to public RPC logs for a shorter window. Typical paid response: about 1-2 s. Data collection has a 3.5 s budget; if a source is slow you still get a report with "partial": true and the scanned window stated per chain in chains[].window. It is a heuristic over a window of public data: always confirm the full address with the payee.

Example (the May 2024 $68M WBTC case): from=0x1E227979f0b5BC691a70DEAed2e0F39a6F538FD5&to=0xd9A1C3788D81257612E2581A6ea0aDa244853a91 returns danger / possibly_already_poisoned: the victim did send real value to that address, but it first appeared in their history through a zero-value transfer.

OpenAPI: /openapi.json · Terms: /terms

Layout

  • cli/: npm package devx-address-poisoning-check (CLI + stdio MCP), npm test
  • worker/: the Cloudflare Worker behind the hosted API (npm run build)

MIT. Made by DevX · madebydevx@gmail.com

Frequently asked questions

What is Address Poisoning Check?

Before sending crypto, check the recipient for address poisoning: lookalikes and bad checksums

How do I install Address Poisoning Check?

It runs as a remote server. In Claude Code: claude mcp add --transport http address-poisoning-check 'https://address-poisoning-check.nextill-pos.workers.dev/mcp'. For other clients, paste the JSON configuration from this page into their MCP settings.

Does Address Poisoning Check need an API key?

Its registry entry lists no required key or secret. Some features may still need an account with the service it connects to.

Is Address Poisoning Check open source?

Yes. Its code is on GitHub under the MIT license.

Who maintains Address Poisoning Check?

It is published by devx-agent. AI.tn lists it but does not maintain or endorse it.

From the official MCP Registry. Listing is not an endorsement: review a server's code and permissions before giving it access to your data.