simplefin-mcp

A tiny, dependency-free, read-only MCP server for balances and transactions from SimpleFIN Bridge.

Tools

• get_accounts: balances for all connected accounts.
• get_transactions: transactions and balances for a requested date range.

SimpleFIN access URLs are read-only. This server has no tools for transferring money or modifying financial accounts.

Requirements

• Node.js 18 or newer.
• A SimpleFIN Bridge account and one-time setup token.

Setup

Claim a new setup token:

node claim.cjs '<setup-token>'

The resulting access URL is stored at ~/.simplefin/access_url with mode 0600. On macOS, the server can alternatively read a generic-password Keychain item:

• Service: Codex SimpleFIN Bridge
• Account: the current macOS username

Register the server with any stdio MCP client:

{
  "mcpServers": {
    "simplefin": {
      "command": "node",
      "args": ["/absolute/path/to/simplefin-mcp/server.cjs"]
    }
  }
}

Environment variables

• SIMPLEFIN_ACCESS_FILE: override the access-URL file.
• SIMPLEFIN_KEYCHAIN_SERVICE: override the macOS Keychain service.
• SIMPLEFIN_KEYCHAIN_ACCOUNT: override the macOS Keychain account.

Security

• Never commit the access URL; it embeds credentials.
• Prefer full-disk encryption and a mode-0600 file or OS Keychain.
• SimpleFIN Bridge may impose request limits, so use modest date ranges and cache results when appropriate.

Test

npm test

The test verifies the MCP handshake and tool schemas without accessing SimpleFIN.

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