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X402 Mcp Bridge MCP Server

by Hpp Io
Developer ToolsModerate6.2MCP RegistryLocal
Free

Server data from the Official MCP Registry

MCP bridge for autonomous x402 payments in HPP USDC.e — discover and pay for services per call.

About

MCP bridge for autonomous x402 payments in HPP USDC.e — discover and pay for services per call.

Security Report

6.2
Moderate6.2Moderate Risk

This is an MCP bridge for HPP x402 payments with generally sound architecture and appropriate permission scoping for its financial purpose. The server properly handles cryptographic keys through OS keychains, uses proper dependency versions, and implements spend guards. However, several code quality and security concerns exist: incomplete input validation in discovery/describe operations, potential unsafe JSON parsing in the CLI, missing error handling in key operations, and inadequate logging of sensitive financial transactions. The permissions are appropriate for a payment application, but better validation and error resilience would strengthen the implementation. Supply chain analysis found 1 known vulnerability in dependencies (0 critical, 1 high severity). Package verification found 1 issue.

5 files analyzed · 12 issues found

Security scores are indicators to help you make informed decisions, not guarantees. Always review permissions before connecting any MCP server.

Permissions Required

This plugin requests these system permissions. Most are normal for its category.

env_vars

Check that this permission is expected for this type of plugin.

File System Read

Reads files on your machine. Normal for tools that analyze or process local data.

File System Write

Writes or modifies files on your machine. Check that this is expected for the tool.

HTTP Network Access

Connects to external APIs or services over the internet.

network_websocket

Check that this permission is expected for this type of plugin.

system_info

Check that this permission is expected for this type of plugin.

process_spawn

Check that this permission is expected for this type of plugin.

What You'll Need

Set these up before or after installing:

Delegate EOA private key used to sign payments. Auto-created in the OS keychain if unset.Required

Environment variable: DELEGATE_PRIVATE_KEY

Target network: eip155:181228 (HPP Sepolia, default) or eip155:190415 (HPP Mainnet).Optional

Environment variable: HPP_NETWORK

Optional upstream MCP server to proxy. Omit to expose only the local tools.Optional

Environment variable: RESOURCE_SERVER_URL

Safe address for governance (Safe) mode. Set together with ALLOWANCE_MODULE_ADDRESS.Optional

Environment variable: SAFE_ADDRESS

Safe AllowanceModule address for governance (Safe) mode. Set together with SAFE_ADDRESS.Optional

Environment variable: ALLOWANCE_MODULE_ADDRESS

How to Install

Add this to your MCP configuration file:

{
  "mcpServers": {
    "io-github-hpp-io-x402-mcp-bridge": {
      "env": {
        "HPP_NETWORK": "your-hpp-network-here",
        "SAFE_ADDRESS": "your-safe-address-here",
        "RESOURCE_SERVER_URL": "your-resource-server-url-here",
        "DELEGATE_PRIVATE_KEY": "your-delegate-private-key-here",
        "ALLOWANCE_MODULE_ADDRESS": "your-allowance-module-address-here"
      },
      "args": [
        "-y",
        "@hpp-io/x402-mcp-bridge"
      ],
      "command": "npx"
    }
  }
}

Documentation

View on GitHub

From the project's GitHub README.

@hpp-io/x402-mcp-bridge

npm MCP Registry License Node

The agent payment rail for HPP. A stdio MCP bridge + the hpp-x402 CLI that let Claude Desktop / Claude Code / Cursor / Windsurf / OpenClaw make autonomous HPP USDC.e payments over x402 — discover paid services, pay per call, within a spend cap. No API keys, no manual signing.

📖 Full documentation

hpp-io/x402-tools — the complete manual: how it works, every command, buyer and seller flows, payment schemes (exact / upto), wallet modes, and troubleshooting. This README is a quick reference.

Install

# macOS / Linux
curl -fsSL https://raw.githubusercontent.com/hpp-io/x402-tools/main/install/install.sh | bash
# Windows (PowerShell)
irm https://raw.githubusercontent.com/hpp-io/x402-tools/main/install/install.ps1 | iex
# …or npm
npm install -g @hpp-io/x402-mcp-bridge

Needs Node 20+. On a headless box (no OS keychain) use setup --print-key — see the manual.

Quick start

hpp-x402 setup --install claude-code   # create a wallet + register into your host
hpp-x402 fund                          # where to send USDC.e (gasless, no native gas)
hpp-x402 status                        # confirm it's wired

Restart your host and your agent can discover and pay for services. Browse and pay from the terminal too:

hpp-x402 discover "price prediction"               # semantic search; your network only
hpp-x402 describe <id>                             # input args (schema + example) — no payment
hpp-x402 call <url-or-id> --body '{"hi":"there"}'  # pay + call — a URL, or an id from discover

Full command reference, selling (serve), schemes, and Safe mode → the manual.

Use it from an MCP host

The host spawns the bridge over stdio. A bare entry boots zero-config on HPP Sepolia with an auto-created keychain wallet:

{ "mcpServers": { "hpp-x402": {
  "command": "npx", "args": ["-y", "@hpp-io/x402-mcp-bridge"]
} } }

hpp-x402 install <host> writes this for you. Note: a bare npx @hpp-io/x402-mcp-bridge runs the MCP server (what the host wants) — for the CLI use npx -y -p @hpp-io/x402-mcp-bridge hpp-x402 <command>.

Host-facing tools

ToolWhat it does
wallet_addressreport your wallet address (to fund it)
hpp_discoverlist/search the curated HPP directory (read-only)
hpp_describeone service's input args — schema + example (read-only)
hpp_callcall a discovered service (HTTP/MCP/A2A); pays via your wallet
x402_http_callpay + call any x402 HTTP endpoint
pay_a2a_agentpay + message another A2A agent

Every paid call stays within your spend cap; discovery never holds funds or sees your keys.

Key env (all optional)

VarNotes
DELEGATE_PRIVATE_KEYauto-created in the OS keychain if unset
HPP_NETWORKeip155:181228 Sepolia (default) / eip155:190415 Mainnet
RESOURCE_SERVER_URLproxy one upstream MCP server (omit = local tools only)
SAFE_ADDRESS + ALLOWANCE_MODULE_ADDRESSset both = Safe (governance) mode

Full environment reference + Safe/governance setup are in the manual.

Related

Building an agent / SDK integration (LangChain, OpenAI function-calling, AgentKit, A2A)? See the runnable gallery → hpp-io/hpp-x402-agent-sample

License

Apache-2.0

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