compare_loans
Use this when you have two loan or mortgage quotes with different rates, terms or fees for the same amount and want the payments and lifetime costs side by side. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use th...
This record as markdown: /tools/com-tttkmbb-calcgrid/compare-loans.md
What compare_loans does on Calcgrid
AI agents call compare_loans to retrieve information from Calcgrid without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
fees_a | number | — | Up-front fees of loan A (origination, points, closing costs), paid separately rather than financed. |
fees_b | number | — | Up-front fees of loan B. |
loan_amount | number | Yes | Amount borrowed under both offers. |
term_a_years | number | Yes | Term of loan A in years (fractions allowed; rounded to whole months). Unit: years. |
term_b_years | number | Yes | Term of loan B in years. Unit: years. |
rate_a_percent | number | Yes | Annual nominal rate of loan A in percent; the monthly rate is this / 12. Unit: %. |
rate_b_percent | number | Yes | Annual nominal rate of loan B in percent. Unit: %. |
Parameters from the server's own tool schema.
Why compare_loans is rated Low
Even though compare_loans only reads data, uncontrolled read access leaks sensitive information and racks up API costs: an agent caught in a retry loop can make thousands of calls a minute without anyone noticing.
Attacks that exploit this kind of access
The rule that runs compare_loans safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Calcgrid, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For compare_loans, this is the rule to start with:
compare_loans is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Calcgrid, apply this rule, and every compare_loans call is checked against it from then on.
Questions about compare_loans
Use this when you have two loan or mortgage quotes with different rates, terms or fees for the same amount and want the payments and lifetime costs side by side. Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery. Do not use this when you are replacing an existing loan (use refinance-break-even), only need one loan's payment (use loan-payment), or will sell or repay early (this compares full-term costs and ignores the time value of money). Informational; not financial advice. What it computes: Compares two fixed-rate, fully amortizing loan offers for the same amount: the level monthly payment, total interest, up-front fees and total cost (interest + fees) of each, and which offer costs less over its full term. Example user requests: Compare a 300000 loan at 6% for 30 years with 3000 in fees against 5.5% for 15 years with 5000 in fees. | Which of these two fixed-rate offers has the lower lifetime interest and fees? | 同样贷款30万元，方案A年利率6%期限30年，方案B年利率5.5%期限15年，比较月供和总成本。 Inputs: loan_amount (number); rate_a_percent (number, %); term_a_years (number, years); fees_a (number, optional); rate_b_percent (number, %); term_b_years (number, years); fees_b (number, optional). Complete JSON argument examples: {"loan_amount":300000,"rate_a_percent":6,"term_a_years":30,"fees_a":3000,"rate_b_percent":5.5,"term_b_years":15,"fees_b":5000} | {"loan_amount":25000,"rate_a_percent":7,"term_a_years":5,"rate_b_percent":6,"term_b_years":6,"fees_b":500} Outputs: payment_a, payment_b, total_interest_a, total_interest_b, total_cost_a, total_cost_b, cheaper_loan, monthly_payment_difference, total_cost_difference, comparison, summary. Formula: For each loan: i = rate/1200, n = 12 × term_years, payment = loan_amount × i / (1 − (1 + i)^−n) (loan_amount / n if i = 0); total_interest = payment × n − loan_amount; total_cost = total_interest + fees. cheaper_loan = the loan with the lower total_cost; monthly_payment_difference = payment_a − payment_b; total_cost_difference = total_cost_a − total_cost_b Direct REST fallback: POST https://tttkmbb.com/api/v1/calculate/loan-comparison with the same JSON input fields. Do not guess another /api/* path. Docs: https://tttkmbb.com/finance/loan-comparison.md. It is categorised as a Read tool in the Calcgrid MCP Server, which means it retrieves data without modifying state.
compare_loans accepts 7 parameters: fees_a, fees_b, loan_amount, term_a_years, term_b_years, rate_a_percent, rate_b_percent. Required: loan_amount, term_a_years, term_b_years, rate_a_percent, rate_b_percent. The full parameter table on this page comes from the server's own tool schema.
Register the Calcgrid MCP server in PolicyLayer and add a rule for compare_loans: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Calcgrid. Nothing to install.
compare_loans is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the compare_loans rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for compare_loans. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
compare_loans is provided by the Calcgrid MCP server (https://tttkmbb.com/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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