Skip to main content
Glama
Sign In
@hpp-io/x402-mcp-bridge

@hpp-io/x402-mcp-bridge

Official
by hpp-io
OverviewSchemaSourceRelated ServersDiscussionsAdmin
TypeScript
Remote

@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.

Related MCP server: @coinbase/payments-mcp

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

Pay from your HPP Smart Wallet instead

Rather than funding the agent's key, let it pay from your HPP Smart Wallet under a spending limit you set. In the wallet, open Agents → New, paste the agent's address (hpp-x402 wallet address), issue the delegation, then run the command the wallet shows — it is this, with the value filled in:

hpp-x402 install claude-code -n eip155:190415 --delegation 0x…

Run it on the machine where the agent's key lives. The value is checked against that key and the network before it is written, and again each time the bridge starts. The value can only be used by that key, within the limit, until it expires — but it does end up in your shell history, so treat it like a card with a cap. To stop the agent, revoke the delegation in the wallet.

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 (per-call cap defaults to 1 USDC.e; raise it with wallet_set_limit) and is paid only in allowlisted tokens; 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

HPP_X402_ALLOWED_ASSETS

extra tokens the bridge may pay in (comma-separated addresses). By default only USDC.e (both networks) and HAC (Sepolia test token); a 402 priced in any other token is refused before signing

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. hpp-x402 install <host> --delegation <value> writes it. Checked against the key and the network at install and at boot (a value issued on the other network, revoked, or expired stops the bridge with the reason); without it such accepts are skipped

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

Tool Schema Changelog

Recent tool additions, removals, and schema changes observed during successful MCP inspections.

Loading tool schema changelog…

    This server cannot be deployed

    One endpoint for every MCP toolRayrun runs every MCP server behind one URL and holds the credentials. Each call is decided per client, tool, and argument, then recorded.ray.runAd

    Maintenance

    ActivityMaintained
    ResponsivenessLimited data

    Resources

    Related MCP Connectors

    Related MCP Servers