rent_vs_buy
Rent vs Buy Calculator — Compare the N-year net cost of buying (mortgage, tax, upkeep, minus equity) vs renting, and find the breakeven year.
This record as markdown: /tools/com-wingmanprotocol-agent-gateway/rent-vs-buy.md
What rent_vs_buy does on Gateway
AI agents call rent_vs_buy to retrieve information from Gateway 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 |
|---|---|---|---|
years | number | — | How many years you'll stay (default 7) |
home_price | number | Yes | Purchase price in USD |
down_payment | number | — | Down payment in USD |
monthly_rent | number | Yes | Monthly rent for a comparable place in USD |
mortgage_rate | number | — | Mortgage rate as a PERCENT (default 6) |
rent_inflation | number | — | Annual rent increase as a PERCENT (default 3) |
loan_term_years | number | — | Mortgage term in years (default 30) |
closing_cost_pct | number | — | Closing costs as a PERCENT of price (default 3) |
maintenance_rate | number | — | Annual maintenance as a PERCENT of value (default 1) |
selling_cost_pct | number | — | Selling costs as a PERCENT of sale price (default 6) |
home_appreciation | number | — | Annual home appreciation as a PERCENT (default 3) |
property_tax_rate | number | — | Annual property tax as a PERCENT of value (default 1.1) |
Parameters from the server's own tool schema.
Why rent_vs_buy is rated Low
This is a financial modeling calculator—a decision-support tool that performs mathematical analysis on user-provided parameters (loan terms, maintenance costs, rental rates, etc.). It reads input values and returns computed outputs, analogous to a spreadsheet formula. It does not execute financial transactions, create obligations, modify records, or run commands. While it pertains to a financial decision (rent vs.
From the tool's definition Tool is a calculator that 'Compare[s] the N-year net cost of buying vs renting, and find[s] the breakeven year.' It performs arithmetic on provided inputs to return computed results (comparison and breakeven analysis) without modifying external data,…
Risk signalsHigh parameter count (12 properties)
Attacks that exploit this kind of access
The rule that runs rent_vs_buy safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Gateway, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For rent_vs_buy, this is the rule to start with:
rent_vs_buy 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 Gateway, apply this rule, and every rent_vs_buy call is checked against it from then on.
Questions about rent_vs_buy
Rent vs Buy Calculator — Compare the N-year net cost of buying (mortgage, tax, upkeep, minus equity) vs renting, and find the breakeven year. It is categorised as a Read tool in the Gateway MCP Server, which means it retrieves data without modifying state.
rent_vs_buy accepts 12 parameters: years, home_price, down_payment, monthly_rent, mortgage_rate, rent_inflation, loan_term_years, closing_cost_pct, maintenance_rate, selling_cost_pct, home_appreciation, property_tax_rate. Required: home_price, monthly_rent. The full parameter table on this page comes from the server's own tool schema.
Register the Gateway MCP server in PolicyLayer and add a rule for rent_vs_buy: 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 Gateway. Nothing to install.
rent_vs_buy 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 rent_vs_buy 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 rent_vs_buy. 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.
rent_vs_buy is provided by the Gateway MCP server (https://wingmanprotocol.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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