Mossgate MCP

What mossgate-mcp does

The mossgate-mcp MCP server makes four paid API operations available to an MCP client. Three target Mossgate Trust at https://api.mossgate.dev: a quick token contract verdict, a behavioral profile for a wallet, and a detailed token report. The fourth targets Rue Render at https://rue.mossgate.dev and converts either a URL or supplied HTML into a PDF, PNG, or JPEG.

The trust tools accept an address and an optional chain, which defaults to base. The rendering tool accepts one source type—URL or HTML—and a requested output format. Rendered files are returned as base64 data.

How it works

The mossgate-mcp MCP server communicates with clients through standard input and output using MCP. It is intended to be launched by an MCP-enabled application rather than operated as an interactive command-line utility.

API access is paid through x402 v2 using USDC on Base. The operator supplies an EVM wallet private key and funds that wallet with Base USDC. For each tool call, the wallet signs an EIP-3009 authorization. Gas is sponsored by the payment facilitator, so the wallet does not need ETH for transaction fees. The wallet still needs enough USDC to pay for requests.

A client can first issue MCP initialization and tools/list requests to confirm that the server starts. That discovery check does not call the paid APIs or spend USDC.

Setup and configuration

Node.js 18 or newer is required. The package can be run without cloning through npm:

npx -y mossgate-mcp

Set MOSSGATE_BUYER_PK to the private key of the wallet that will pay for requests. The wallet should hold USDC on Base; the README identifies the USDC contract as 0x833589fcd6edb6e08f4c7c32d4f71b54bda02913. Keep the private key out of source control and client configuration files where possible.

The optional MOSSGATE_RPC variable overrides the Base RPC URL. MOSSGATE_TRUST_URL and MOSSGATE_RENDER_URL can override the default Trust and Rue Render endpoints. A local checkout can also be started with node index.js from the server directory after installing dependencies with npm install.

Tools and capabilities

The mossgate-mcp MCP server exposes these tools:

• token_verdict(address, chain=base): returns a quick risk verdict for a token contract.
• wallet_profile(address, chain=base): returns a behavioral risk profile for a wallet.
• token_report(address, chain=base): returns a full token report.
• render(url|html, format=pdf|png|jpeg): renders a URL or HTML input into the selected file format and returns base64 output.

Claude Desktop can launch the server through its MCP configuration. Other MCP clients may also use it if they support local stdio servers and can provide the required environment variable.

Limitations and notes

Every tool call to the live APIs spends USDC from the configured wallet. The server is therefore not suitable for unattended use unless the operator accepts and monitors that payment behavior. The README does not provide individual tool prices, response schemas, rate limits, or support for chains other than the default Base setting.

The private key grants control over the payment wallet and must be protected. No ETH is needed for gas according to the provided setup instructions, but USDC on Base is required. Rendering output is returned as base64 rather than written to a specified local file.

Getting started with this mossgate-mcp MCP server

Always refer to the official documentation for the most accurate and up-to-date information.