# HPP x402 MCP Bridge [Health: Active]

**Category:** 💰 Finance & Fintech  
**Repository:** https://github.com/hpp-io/x402-mcp-bridge  
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**Directory Page:** https://allmcps.com/mcp/hpp-x402-mcp-bridge

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

## Claude Desktop Quick Installation
Install path detected from listing signals. Uses `npx` (confidence: high):

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

## Documentation

## What HPP x402 MCP Bridge does

HPP x402 MCP Bridge gives MCP hosts access to HPP's x402 payment flow. Agents can search the curated HPP service directory, inspect a service's input schema and example, then invoke the service while paying from an agent wallet. Payment is made in HPP USDC.e, and each paid call is constrained by the configured spending cap.

The bridge supports calls to discovered HTTP, MCP, and A2A services. It also includes a tool for calling arbitrary x402 HTTP endpoints and another for paying and messaging an A2A agent. Read-only discovery does not handle funds or expose wallet keys.

## How it works

An MCP host starts the bridge as a child process over stdio. A minimal host configuration can run the package through `npx`:

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

The bridge can create a wallet key in the operating system keychain when no private key is supplied. Agents can report the wallet address, search the HPP directory, inspect service requirements, and submit paid calls. The separate `hpp-x402` command-line interface provides equivalent terminal workflows through commands such as `discover`, `describe`, and `call`.

Payment can instead use an HPP Smart Wallet delegation. The delegation is issued to the agent's address and limited by the wallet owner, including an expiration and spending limit. The bridge validates the delegation against the agent key and selected network when installed and when it starts.

## Setup and configuration

Install with the project installer for macOS or Linux, the PowerShell installer for Windows, or npm:

```bash
npm install -g @hpp-io/x402-mcp-bridge
```

Node.js 20 or newer is required. Run `hpp-x402 setup --install <host>` to create a wallet and register the bridge with a supported host, then use `hpp-x402 fund` to obtain the wallet funding destination and `hpp-x402 status` to verify the setup. A headless machine without an operating-system keychain can use `setup --print-key`.

The default network is HPP Sepolia. `HPP_NETWORK` selects between HPP Sepolia and HPP Mainnet. `DELEGATE_PRIVATE_KEY` supplies the agent key; if omitted, the bridge can create and store one in the OS keychain. `HPP_PAYMENT_DELEGATION` enables delegated payment from a user's smart account. `RESOURCE_SERVER_URL` can proxy one upstream MCP server, while `SAFE_ADDRESS` and `ALLOWANCE_MODULE_ADDRESS` together enable Safe governance mode.

## Tools and capabilities

- `wallet_address` reports the wallet address used for funding or delegation.
- `hpp_discover` searches the curated HPP directory without making payments.
- `hpp_describe` returns a service's input arguments, schema, and example.
- `hpp_call` pays for and invokes a discovered HTTP, MCP, or A2A service.
- `x402_http_call` pays for and invokes any x402 HTTP endpoint.
- `pay_a2a_agent` pays and sends a message to another A2A agent.

## Limitations and notes

The bridge is intended for HPP x402 payments and defaults to HPP Sepolia. Mainnet use requires selecting the Mainnet network. A bare package invocation starts the MCP server; CLI commands require invoking the `hpp-x402` executable separately.

Delegation values are checked against the agent key and network, and revoked, expired, or cross-network delegations prevent the bridge from starting. Delegation values written through installation may remain in shell history, so they should be handled like capped payment credentials. Discovery is limited to the curated HPP directory, while arbitrary endpoint access is available through the dedicated x402 HTTP tool.

_Full upstream README: https://allmcps.com/mcp/hpp-x402-mcp-bridge/readme_