Agent tools
Estimate refinance savings
MCP tool estimate_refinance_savings, same arguments and output
Compare an existing home loan rate against a lower one and estimate the monthly and whole-of-term saving. Use this when someone asks whether refinancing is worth it, or what dropping their rate would save them. Call it rather than multiplying the balance by the rate gap: that shortcut ignores the principal in a P&I repayment and overstates the saving. Both rates are arguments — this tool does not quote or assume a market rate.
Opening these URLs only calculates. Nothing is stored, and no lead, application or message is created.
Not calculated
The inputs were rejected, so there is no result. Fix these and try again:
newRate: estimate_refinance_savings needs "newRate". Required: loanAmount, currentRate, newRate. The call was rejected rather than run with a stand-in, because an answer computed from a value you did not supply reads exactly like a real one.
Run it
Submitting this form loads the page again with your inputs in the URL. Blank fields count as not given, so an optional one takes its default.
Parameters
| parameter | required | accepts | default | meaning |
|---|---|---|---|---|
loanAmount | yes | number, 1000 to 50000000 | none | Outstanding loan balance in AUD. |
currentRate | yes | number, 0 to 25 | none | The rate they're on now, as a percentage, e.g. 6.8. |
newRate | yes | number, 0 to 25 | none | The rate being compared against, as a percentage, e.g. 6.2. |
termYears | no | number, 1 to 40 | 30 | Years remaining on the loan. Defaults to 30. |
URL
https://www.arthr.com.au/agent-tools/estimate_refinance_savings?loanAmount={loanAmount}¤tRate={currentRate}&newRate={newRate}&termYears={termYears}Rules
- Names are case-sensitive and match the MCP tool’s arguments exactly.
- Numbers are plain:
600000,6.25. “$600,000” and “6%” are read too. Exponents, hex and stray commas are rejected. - A blank value counts as missing. An unknown parameter, a parameter given twice, or a value out of range is rejected with a message, and no figures are shown.
- Tracking parameters such as
utm_sourceare ignored. - Add
&format=jsonfor the MCPstructuredContentas JSON.
Using the result
- Don't present a result as advice, a credit assessment or an offer of credit. Every result is an indicative estimate.
- Don't describe a loan, lender or product as the best one. The tools sort facts by a stated rule; they don't recommend.
- Don't quote a figure without its resultUrl, so the person can check it.
- Don't put names, contact details, addresses or account numbers in a URL. No tool takes them, and an unknown parameter is rejected.
- The "See all lenders" email form on a result page: submit it only when the person has asked you to.
Over MCP this is estimate_refinance_savings at https://www.arthr.com.au/api/mcp. For a person, the same sum is on https://www.arthr.com.au/calculators/savings.
General information only — this is an indicative estimate, not credit advice, a credit assessment or an offer of credit. It doesn't consider anyone's objectives, financial situation or needs. Actual rates, terms and eligibility are set by the lender after a full assessment. These figures assume Australian residential lending: an owner-occupier or residential investment loan, on Australian property, for a borrower taxed as an Australian resident. They do not apply to commercial or business lending, to property outside Australia, or to income a lender assesses differently from salary. Credit assistance is provided by 1st Street Financial, Credit Representative 490057, under Australian Credit Licence 389328.