{"service": "calculator-api", "endpoints": {"POST /evaluate": {"body": {"equation": "string, e.g. 'y = x^2 + 2x - 1'", "x_min": "number (default -10)", "x_max": "number (default 10)", "num_points": "integer 1..2000 (default 100)"}, "returns": "{equation, x_min, x_max, num_points, points:[{x, y}]}"}, "GET /health": {"returns": "{status: 'ok'}"}}}