What is HPP x402 MCP Bridge?

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

How do I install HPP x402 MCP Bridge?

Install HPP x402 MCP Bridge via npm from https://registry.npmjs.org, then add the server config to your MCP client (Claude Desktop, Cursor, or VS Code).

Is HPP x402 MCP Bridge open source?

Yes, HPP x402 MCP Bridge is open source under the NOASSERTION license. Source code is available at https://github.com/hpp-io/x402-mcp-bridge.

What category does HPP x402 MCP Bridge belong to?

HPP x402 MCP Bridge is listed under Other MCP servers on MCPFind.

HPP x402 MCP Bridge — MCP Server for Other

@hpp-io/x402-mcp-bridge

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

Tool	What it does
`wallet_address`	report your wallet address (to fund it)
`hpp_discover`	list/search the curated HPP directory (read-only)
`hpp_describe`	one service's input args — schema + example (read-only)
`hpp_call`	call a discovered service (HTTP/MCP/A2A); pays via your wallet
`x402_http_call`	pay + call any x402 HTTP endpoint
`pay_a2a_agent`	pay + message another A2A agent

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

Key env (all optional)

Var	Notes
`DELEGATE_PRIVATE_KEY`	auto-created in the OS keychain if unset
`HPP_NETWORK`	`eip155:181228` Sepolia (default) / `eip155:190415` Mainnet
`RESOURCE_SERVER_URL`	proxy one upstream MCP server (omit = local tools only)
`SAFE_ADDRESS` + `ALLOWANCE_MODULE_ADDRESS`	set both = Safe (governance) mode
`HPP_PAYMENT_DELEGATION`	ERC-7710 payment delegation a wallet granted to this key: pays `erc7710` accepts from the user's smart account under on-chain caps — this key needs no USDC.e. Validated at boot; without it such accepts are skipped

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

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

Set up in your AI client

AI clientOperating system

Merge this template into ~/Library/Application Support/Claude/claude_desktop_config.json. Keep existing servers. Add any arguments, credentials, and permissions required by the maintainer; this template has not been install-tested.

json

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

Restart Claude Desktop completely for changes to take effect. Confirm the server appears connected in the client’s tool list, then try a read-only example from its documentation.

Claude Desktop setup reference

Compatible MCP Clients

HPP x402 MCP Bridge works with any MCP-compatible client. Copy the config snippet from the Configuration section above and add it to the file shown for your client, then restart the application.

Claude Desktop~/Library/Application Support/Claude/claude_desktop_config.jsonRestart Claude Desktop completely for changes to take effect.

Cursor~/.cursor/mcp.jsonRestart Cursor for changes to take effect.

VS Code.vscode/mcp.jsonReload VS Code window for changes to take effect.

Windsurf~/.codeium/windsurf/mcp_config.jsonRestart Windsurf for changes to take effect.

Claude Code.mcp.jsonSave at the project root, then start Claude Code in that project and review the MCP server approval prompt. Keep real credentials out of shared files.

HPP x402 MCP Bridge