x402-mcp-caller

name: x402-mcp-caller description: Use this skill to call MCP server tools with x402 crypto payment support. Enables testing and interacting with paid MCP services across multiple EVM blockchain networks (Base, Avalanche, SKALE, Ethereum, Optimism, Arbitrum, Polygon). Invoke when user wants to test MCP servers, make paid API calls, or interact with x402-enabled services.

X402 MCP Tool Caller

This skill enables calling MCP (Model Context Protocol) server tools with automatic x402 payment handling. It supports paid services that require cryptocurrency payments on EVM-compatible blockchains.

When to Use

Testing MCP servers that implement x402 payment protocol
Making paid API calls to MCP services
Listing available tools on an MCP server
Interacting with x402-enabled services across different blockchain networks

Prerequisites

EVM_WALLET_PRIVATE_KEY environment variable must be set for paid calls
The wallet must have sufficient funds on the target network

Usage

The skill uses the script at scripts/mcp_x402_call.py.

List Available Tools

uv run scripts/mcp_x402_call.py <server_url> --list-tools

Call a Tool (Free)

uv run scripts/mcp_x402_call.py <server_url> <tool_name> '<json_arguments>'

Call a Tool (With Payment)

uv run scripts/mcp_x402_call.py <server_url> <tool_name> '<json_arguments>' --pay

Specify Network

uv run scripts/mcp_x402_call.py <server_url> <tool_name> '<json_arguments>' --pay --network <network>

Available networks: base, avalanche, skale, ethereum, optimism, arbitrum, polygon

Examples

# List tools on a server
uv run scripts/mcp_x402_call.py https://prod.mcp-lurky.xyber.inc/mcp-server/mcp/ --list-tools

# Search tweets with payment on Base network (default)
uv run scripts/mcp_x402_call.py https://prod.mcp-lurky.xyber.inc/mcp-server/mcp/ search_tweets '{"query": "AI"}' --pay

# Call tool with payment on Avalanche
uv run scripts/mcp_x402_call.py http://localhost:8113/mcp/ search_token_address '{"query": "ETH"}' --pay --network avalanche

# Call tool on SKALE network
uv run scripts/mcp_x402_call.py https://example.com/mcp/ some_tool '{"param": "value"}' --pay --network skale

Arguments Reference

Argument	Required	Description
`base_url`	Yes	MCP server URL (e.g., `https://server.com/mcp/`)
`tool_name`	No	Tool to call (omit to list tools)
`arguments`	No	JSON string with tool arguments (default: `{}`)
`--list-tools`, `-l`	No	List available tools
`--pay`, `-p`	No	Enable x402 payment
`--network`, `-n`	No	Preferred payment network

Response Handling

On success: Returns JSON response from the tool
On 402 Payment Required: Shows payment details (use --pay flag)
Payment transactions are logged with tx hash and network