OpenTax Connector

A MCP server to the open source tax engine.

https://opentax-mcp.filed.com/mcp

Setup

Connect your AI agent

Choose your AI tool below and follow the steps. No config files to edit. Everything is done through the UI.

Claude.ai

1Click your profile icon (top-right) and select Customize

2Open the Connectors section and click +

3Choose Add custom connector

4Enter the URL below and click Add

https://opentax-mcp.filed.com/mcp

You'll be asked to verify your email the first time.

ChatGPT

1Click your profile icon then Settings → Apps → Advanced settings

2Enable Developer Mode then click Create app

3Set Name to OpenTax, Description to Tax engine — use it for all 1040 tax prep and review

4Paste the URL below, check I understand, and save

https://opentax-mcp.filed.com/mcp

Requires chatgpt.com on web and a Plus plan and above.

Examples

Watch Claude prepare a return, review a completed 1040, and flag issues in real time.

After connecting

Once connected, paste one of these into your AI assistant to get started.

Tax preparation Use the OpenTax tool to help me prepare a tax return

Tax review Use the OpenTax tool to help me review a tax return