{"openapi":"3.0.3","info":{"title":"Gnist Context — Mortgage Calculator","description":"Mortgage payment calculator — monthly payments, amortization schedules, and affordability estimates.\n\n- **MCP endpoint:** `https://context.gnist.ai/mcp/mortgage-calculator/`\n- **Toolkit page:** `/toolkits/mortgage-calculator`\n- **Full API spec:** `/api/openapi.json`\n- **Get an API key:** `/signup`","version":"1.0.0","contact":{"name":"GnistAI","url":"https://gnist.ai"}},"servers":[{"url":"https://context.gnist.ai","description":"Production"}],"paths":{"/rest/mortgage-calculator/calculate_monthly_payment":{"post":{"tags":["Finance"],"summary":"calculate_monthly_payment","description":"Calculate fixed monthly mortgage payment.\n\nGiven a loan amount, interest rate, and term, computes the monthly payment,\ntotal amount paid over the life of the loan, and total interest.","operationId":"mortgage_calculator_calculate_monthly_payment","responses":{"200":{"description":"Successful tool 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of gross\nmonthly income, minus existing debts.","operationId":"mortgage_calculator_calculate_affordability","responses":{"200":{"description":"Successful tool call","content":{"application/json":{"schema":{"type":"object"}}}},"404":{"description":"Server or tool not found"},"500":{"description":"Tool execution error"}},"security":[{"ApiKeyHeader":[]},{"ApiKeyQuery":[]}],"requestBody":{"required":true,"content":{"application/json":{"schema":{"additionalProperties":false,"properties":{"annual_income":{"description":"Gross annual income.","type":"number"},"annual_rate":{"description":"Annual interest rate as a percentage (e.g. 5.5 for 5.5%).","type":"number"},"monthly_debts":{"default":0.0,"description":"Existing monthly debt obligations.","type":"number"},"down_payment":{"default":0.0,"description":"Cash available for down payment.","type":"number"},"term_years":{"default":30,"description":"Loan term in 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