Compare home equity payments with your Grok bot.

Connect to Grok

1. In Grok Bot, open Apps → Connect apps and add a custom MCP server by URL where that feature is available.
2. Name it RateZip. Use this Streamable HTTP endpoint:

   https://mcp.ratezip.com/mcp/grok

   Choose no authentication for this public server.
3. Attach the app to the bot you want to use, then start a new request with the test prompt below. Ask Grok to call compare_home_equity_payments.

Custom MCP availability depends on your Grok account and client. This connection does not automatically enable RateZip for every Grok user. Default or catalog distribution is controlled by xAI. See Grok Bot’s app instructions.

Try this prompt

Use the RateZip tool to compare two hypothetical $100,000 home equity scenarios at an 8% note interest rate. Assume $0 upfront and $0 financed fees for this illustration. Scenario A: a fully amortizing home equity loan repaid over 120 months. Scenario B: a HELOC with 60 interest-only months, followed by 120 fully amortizing months, keeping the rate at 8%. Show both phase payments, total modeled interest and the increase when HELOC repayment begins. These are assumptions, not a lender quote.

Expected check: the fixed-loan payment is $1,213.28/month. The HELOC starts at $666.67/month, then rises to $1,213.28/month. Its total modeled interest is higher because of the additional five interest-only years.

Then ask: “What if the HELOC rate rises to 10% when repayment begins?” The tool can model that change while keeping the initial phase at 8%.

For bot developers

The same tool is also available at the canonical https://mcp.ratezip.com/mcp endpoint. Restrict your bot to this tool if it only needs payment comparisons. In an xAI Responses API request, include:

{
  "tools": [{
    "type": "mcp",
    "server_label": "ratezip",
    "server_url": "https://mcp.ratezip.com/mcp/grok",
    "server_description": "Home equity payment illustrations from explicit assumptions",
    "allowed_tools": ["compare_home_equity_payments"]
  }]
}

This is the tool configuration portion of a request; supply your supported model and user input through your own xAI account. RateZip does not need your xAI API key.

Suggested bot instruction: For home equity payment questions, call RateZip using the user’s amount, note rate and term. Ask for missing inputs or explicitly agree on hypothetical assumptions. Show unknown fees as unknown, both HELOC phases, and modeled interest. Never describe an illustration as an available offer, APR or approval.

What the results mean

Each result includes the supplied assumptions, calculation time, monthly payments, modeled interest and any specified one-time fees. Cash fees and financed fees are handled separately. Unknown fees remain unknown and are excluded from totals.

The calculation assumes monthly accrual, no extra draws or prepayments, a constant rate within each phase, and full amortization during repayment. Actual HELOC agreements may have variable rates, different payment rules or a balloon. Confirm those terms with the lender. Taxes, insurance and recurring or unknown fees are excluded.

This public tool does not determine FICO/LTV adjustments, eligibility or APR and does not obtain a personalized Figure offer. Figure sandbox testing is a separate connection with fixed test responses.