🧠 Gusto MCP Server

A Model Context Protocol (MCP) server that integrates with Gusto's payroll API to expose structured tools for use by LLM agents. This server enables authenticated access to company-level resources, including payroll, employee, and pay schedule data.

⚠️ Note: This is a proof of concept (POC) and currently supports the Gusto sandbox environment. To use it in production, update GustoApiService to point to the production endpoint.

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📋 Prerequisites

• Node.js (v18 or higher)
• npm
• A Gusto developer account with access to a demo company

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📚 Docs & Resources

• 📘 Gusto API Documentation
• 📘 Model Context Protocol (MCP)

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⚙️ Setup

🔐 1. Create a Gusto Developer Account

• Sign up at the Gusto Developer Portal
• Choose the Embedded Payroll integration type
• Create a demo company to generate access and refresh tokens

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🔐 2. Authentication Notes

• This implementation uses company-level tokens (OAuth2)
• Tokens are automatically refreshed while the server is running
• ⚠️ Current Limitation: If the server restarts, you'll need to re-inject the most recent tokens manually

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💻 3. Run Locally / Integrate with Claude Desktop

Install dependencies:

npm install

Build the project:

npm run build

Update Claude desktop config:

Open Settings > Developer > Edit config and update your claude_desktop_config.json:

{
  "mcpServers": {
    "gusto": {
      "command": "node",
      "args": [
        "/path-to-your-project-folder/gusto-mcp/build/index.js"
      ],
      "env": {
        "GUSTO_BASE_URL": "https://api.gusto-demo.com",
        "GUSTO_CLIENT_ID": "your-client-id",
        "GUSTO_CLIENT_SECRET": "your-client-secret",
        "GUSTO_ACCESS_TOKEN": "initial-access-token",
        "GUSTO_REFRESH_TOKEN": "company-refresh-token"
      }
    }
  }
}

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🚀 Available MCP Tools (Overview)

This server exposes tools that allow LLMs to:

• View payroll status, check dates, and blockers
• Retrieve employee data including jobs and compensations
• Access pay schedule details