Tossinvest MCP

What scjang01/tossinvest-mcp MCP server does

The scjang01/tossinvest-mcp MCP server connects MCP clients running on a user’s computer to the Toss Securities Open API. Its read-only capabilities cover domestic and U.S. stock information, including current prices, order books, recent trades, candles, upper and lower price limits, basic instrument details, purchase warnings, exchange rates, and market hours.

Account-oriented queries include available accounts, holdings, buying power, sellable quantities, trading fees, order lists, and order details. These functions are available without enabling trading. The default account is account sequence 1, and another account can be selected through configuration.

Trading is optional. When enabled, the server registers tools for creating, modifying, and cancelling orders. A modification replaces the original order rather than patching it in place, so Toss returns a new order ID that must be used for later lookups, modifications, or cancellation.

How it works

The scjang01/tossinvest-mcp MCP server runs locally through Node.js and communicates with the MCP client over its local process connection. The npm package can be launched with npx, allowing the client to fetch it when first started. Toss Securities API credentials are passed as environment variables rather than written into tool requests.

OAuth token handling is internal: the server obtains tokens and refreshes them automatically before expiry. Toss Securities only accepts requests from registered IP addresses, so the machine’s public IP must be added to the allowed IP list in the Toss Securities WTS Open API settings.

Trading tools are not registered by default. If trading is enabled, each create, modify, or cancel request normally also needs the input field confirmOrderAction: true. This confirmation requirement can be disabled for automation, but other configured restrictions continue to apply.

Setup and configuration

Install Node.js 20 or newer, obtain a Toss Securities API Key and Secret Key, and register the machine’s public IP with Toss Securities. Add the server to the MCP client configuration with npx tossinvest-mcp, setting TOSSINVEST_API_KEY and TOSSINVEST_SECRET_KEY in the environment.

TOSSINVEST_ACCOUNT selects the default account sequence and otherwise defaults to 1. Set TOSSINVEST_ENABLE_TRADING to true only when real-account order operations are intended. The scjang01/tossinvest-mcp MCP server does not provide a sandbox, so initial testing should use market-data and account-query functions before enabling trading.

Tools and capabilities

The scjang01/tossinvest-mcp MCP server supports:

• Domestic and U.S. stock quotes, order books, trades, candles, and instrument information
• Exchange rates and domestic/U.S. market schedules
• Account lists, holdings, buying power, sellable quantities, fees, and order details
• Optional order creation, modification, and cancellation
• Local pre-trade restrictions for order amount, daily amount, daily count, symbols, selling, market orders, and account selection

Limitations and notes

All order operations can affect a real Toss Securities account. There is no documented mock-trading or sandbox environment. By default, selling and market orders are blocked, and order confirmation is required. Additional limits can restrict one-order amounts, daily totals, daily order counts, permitted symbols, and the account used for orders.

The server requires valid Toss Securities credentials and an allowed source IP. Protect the API Key and Secret Key. Account-dependent requests use the configured default account unless a supported request specifies otherwise, and account locking can prevent orders from targeting a different account.