payment is x402 v2, usdc on base. the operator who runs this server funds a wallet, and every tool call spends a little usdc from it. the wallet signs an eip-3009 authorization gaslessly, so it needs only usdc, no eth for gas.

tools

token_verdict(address, chain=base) quick risk verdict for a token contract
wallet_profile(address, chain=base) behavioural risk profile for a wallet
token_report(address, chain=base) full token report
render(url|html, format=pdf|png|jpeg) render a page, returns a base64 file

install

cd mcp-server
npm install

node 18+ is required.

fund the wallet

create or reuse an evm wallet (any tool that gives a 0x private key).
send it usdc on base (contract 0x833589fcd6edb6e08f4c7c32d4f71b54bda02913). a few dollars covers many calls. no eth is needed, gas is sponsored by the facilitator.
export the private key as an env var (never commit it):

export MOSSGATE_BUYER_PK=0xyourprivatekey

optional overrides: MOSSGATE_RPC (base rpc url), MOSSGATE_TRUST_URL, MOSSGATE_RENDER_URL.

run standalone

MOSSGATE_BUYER_PK=0x... node index.js

the server speaks mcp over stdio. it is meant to be launched by an mcp client, not used by hand.

claude desktop / mcp client config

add this to your mcp client config (for claude desktop: ~/.config/Claude/claude_desktop_config.json on linux, or ~/Library/Application Support/Claude/claude_desktop_config.json on macos):

{
    "mcpServers": {
        "mossgate": {
            "command": "node",
            "args": ["/absolute/path/to/products/mcp-server/index.js"],
            "env": {
                "MOSSGATE_BUYER_PK": "0xyourprivatekey"
            }
        }
    }
}

restart the client. the four tools appear and each call is paid automatically from the funded wallet.

verify it starts (no paid calls)

this lists the tools over stdio without touching the apis or spending anything:

printf '%s\n' \
'{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2025-06-18","capabilities":{},"clientInfo":{"name":"probe","version":"0"}}}' \
'{"jsonrpc":"2.0","method":"notifications/initialized"}' \
'{"jsonrpc":"2.0","id":2,"method":"tools/list","params":{}}' \
| node index.js

publish later

this package is not published yet. when ready:

cd mcp-server
npm login
npm publish --access public

after publishing, users can run it without cloning via npx mossgate-mcp (set the command to npx and args to ["-y", "mossgate-mcp"] in the client config).