Sekisho MCP

@zero-two-labs/sekisho-mcp

A local MCP server that lets OpenCode, Claude Code, Codex or any MCP client use paid MCP tools. It connects to a remote MCP server that charges per call with x402 (USDC on Avalanche), shows its tools to your agent, and pays the paid ones from your wallet, never above your caps.

• Per-call cap (SEKISHO_MAX_PER_CALL, default 0.01 USDC): a tool that costs more is refused, nothing is signed.
• 24-hour cap (SEKISHO_MAX_PER_DAY, default 0.10 USDC): kept in a file on disk, so it holds across restarts and sessions.
• The key never goes in your editor config. It is read from a private file (chmod 600); the proxy refuses a file other users can read.
• Prices in tool descriptions. After the first call the agent sees what each tool costs (and whether it is above your cap), so it can decide before paying again.
• Extra free tool sekisho_wallet: payer address, network, caps and what was spent in the last 24 h.

Works with any x402 exact MCP server on Avalanche, not only Sekisho sellers. Paid services you can use with it are listed at sekisho.zerotwolabs.xyz/services. Listed in the MCP Registry as io.github.usainbluntmx/sekisho-mcp.

1. The payer key

Use a wallet only for this, with a small amount of USDC. It does not need AVAX: the seller pays the gas.

mkdir -p ~/.config/sekisho && chmod 700 ~/.config/sekisho
read -s KEY && printf '%s\n' "$KEY" > ~/.config/sekisho/payer.key && chmod 600 ~/.config/sekisho/payer.key && unset KEY

2. OpenCode

In opencode.json (project root) or ~/.config/opencode/opencode.json (global), per the OpenCode MCP docs:

{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "sekisho": {
      "type": "local",
      "command": ["npx", "-y", "@zero-two-labs/sekisho-mcp"],
      "enabled": true,
      "environment": {
        "SEKISHO_MCP_URL": "https://sekisho-api.zerotwolabs.xyz/mcp",
        "SEKISHO_NETWORK": "avalanche",
        "SEKISHO_MAX_PER_CALL": "0.01",
        "SEKISHO_MAX_PER_DAY": "0.50"
      },
      "timeout": 60000
    }
  }
}

Other clients: register a local (stdio) MCP server that runs npx -y @zero-two-labs/sekisho-mcp with the same environment variables.

Configuration

Variable	Default	Meaning
SEKISHO_MCP_URL	(required)	Remote paid MCP server (Streamable HTTP). https, or http on localhost only
SEKISHO_NETWORK	avalancheFuji	avalancheFuji (testnet) or avalanche (mainnet, real USDC)
SEKISHO_MAX_PER_CALL	0.01	Max USDC per tool call
SEKISHO_MAX_PER_DAY	0.10	Max USDC in any 24 h window
SEKISHO_PAYER_KEY_FILE	~/.config/sekisho/payer.key	Private key file (0x + 64 hex, mode 600)
SEKISHO_LEDGER_FILE	~/.config/sekisho/spend.json	Spend log used for the 24 h cap

Agents call paid tools on their own initiative, not only when you ask: keep the caps low. A signed payment counts toward the cap even if the server then fails to settle it. Logs go to stderr; stdout is the MCP protocol.

MIT · Sekisho by Zero Two Labs