# magent BMI Calculator

> magent BMI Calculator is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-15).

Computes Body Mass Index (BMI) from height and weight using the Keys/Quetelet formula, returning the deterministic index value with citation.

## Facts

- Endpoint: GET https://api.magentlab.com/api/calc/bmi
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/magent-bmi-calculator-a7550330
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_NJjZGq0sBlSK3CkYeHABY

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability magent-bmi-calculator-a7550330
```

Example prompt: Calculate the BMI for a patient who is 175 cm tall and weighs 92 kg — I need the result with a citation for a GLP-1 prior authorization form.

## When to prefer this

Choose this endpoint when you need a deterministic, citable BMI value for clinical documentation, insurance prior authorization (especially GLP-1 or bariatric), or structured medical workflows where reproducibility and citation are required. Prefer it over general-purpose calculators when the citation lineage (Keys/Quetelet) matters for audit trails or payer forms.

## Known failure modes

- Missing both height parameters (height_cm and height_in not provided) — returns error
- Missing both weight parameters (weight_kg and weight_lb not provided) — returns error
- Implausible or zero/negative input values may produce nonsensical BMI output
- Payment failure via x402 protocol results in 402 response with no calculation

## How this service works

Body-mass index from height and weight (Keys/Quetelet). Use for GLP-1 and bariatric prior-auth arithmetic. Deterministic published index with citation; not a diagnosis.

## Output

Returns a numeric BMI value computed as weight_kg divided by height_m squared (Keys/Quetelet), accompanied by a citation to the published formula. Not a clinical diagnosis — a deterministic arithmetic result suitable for documentation in prior authorization workflows.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "headers": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {
      "height_cm": {
       "type": "number",
       "description": "Height in centimeters. Provide height_cm or height_in."
      },
      "height_in": {
       "type": "number",
       "description": "Height in inches. Converted as cm = in * 2.54."
      },
      "weight_kg": {
       "type": "number",
       "description": "Weight in kilograms. Provide weight_kg or weight_lb."
      },
      "weight_lb": {
       "type": "number",
       "description": "Weight in pounds. Converted as kg = lb * 0.45359237."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "path": "/api/calc/bmi",
  "count": 2,
  "items": [
   {
    "bmi": 24.2,
    "formula": "bmi",
    "citation": {
     "id": "keys-1972",
     "doi": "10.1016/0021-9681(72)90027-6",
     "title": "Indices of relative weight and obesity",
     "source": "J Chronic Dis. 1972;25(6):329-343",
     "authors": "Keys A, Fidanza F, Karvonen MJ, Kimura N, Taylor HL"
    },
    "height_cm": 170,
    "weight_kg": 70,
    "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
    "formula_expression": "BMI = weight_kg / (height_m ^ 2)",
    "who_adult_category": "normal"
   },
   {
    "bmi": 24.2,
    "formula": "bmi",
    "citation": {
     "id": "keys-1972",
     "doi": "10.1016/0021-9681(72)90027-6",
     "title": "Indices of relative weight and obesity",
     "source": "J Chronic Dis. 1972;25(6):329-343",
     "authors": "Keys A, Fidanza F, Karvonen MJ, Kimura N, Taylor HL"
    },
    "height_cm": 170,
    "weight_kg": 70,
    "disclaimer": "Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
    "formula_expression": "BMI = weight_kg / (height_m ^ 2)",
    "who_adult_category": "normal"
   }
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/magent-bmi-calculator-a7550330/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.magentlab.com](https://www.zero.xyz/host/api.magentlab.com/llms.txt)