# magent NDI Calculator (Vernon 1991)

> magent NDI Calculator (Vernon 1991) is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14).

Computes the Vernon 1991 Neck Disability Index (NDI) raw score and severity band from ten caller-supplied 0–5 item scores

## Facts

- Endpoint: GET https://api.magentlab.com/api/calc/ndi
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/magent-ndi-calculator-vernon-1991-ea0375c5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_EjpnBpHIU-oBTove1buz3

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-ndi-calculator-vernon-1991-ea0375c5
```

Example prompt: Calculate the Vernon 1991 NDI for a patient with these subscores: pain intensity 3, personal care 2, lifting 4, reading 1, headaches 2, concentration 3, work 3, driving 2, sleeping 3, recreation 2 — give me the raw total and severity band.

## When to prefer this

Use this endpoint when you need a strictly Vernon 1991 NDI raw-score calculation with the original 0–4/5–14/15–24/25–34/>34 severity bands. Prefer it over manual summation for auditability and when you need a structured band label returned automatically. Do not use it for percentage-converted NDI variants, Oswestry Disability Index scoring, or any other outcome measure.

## Known failure modes

- Missing any of the ten required query parameters returns an error
- Any subscore outside integer range 0–5 is rejected
- Non-integer or non-numeric input for subscores fails validation
- HTTP 402 if payment header is absent or insufficient (x402 protocol)

## How this service works

Vernon 1991 Neck Disability Index: ten caller-assigned integers 0-5 (pain intensity, personal care, lifting, reading, headaches, concentration, work, driving, sleeping, recreation). Sum 0-50. Vernon 1991 raw-score bands 0-4 none, 5-14 mild, 15-24 moderate, 25-34 severe, >34 complete. Does not apply later 0-8%/10-28% website percentage bands or score Oswestry. magent does not interview. Not a diagnosis and not a medical device.

## Output

Returns the NDI raw sum (integer 0–50, sum of the ten input subscores) and the Vernon 1991 severity band: none (0–4), mild (5–14), moderate (15–24), severe (25–34), or complete (>34). Does not apply percentage-based variants or produce a diagnosis.

## 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": [
      "pain_intensity",
      "personal_care",
      "lifting",
      "reading",
      "headaches",
      "concentration",
      "work",
      "driving",
      "sleeping",
      "recreation"
     ],
     "properties": {
      "work": {
       "type": "integer",
       "description": "Caller-assigned Vernon 1991 NDI work (integer 0-5): 0 can do as much work as wanted through 5 cannot do any work at all. magent does not interview the patient."
      },
      "driving": {
       "type": "integer",
       "description": "Caller-assigned Vernon 1991 NDI driving (integer 0-5): 0 can drive without neck pain through 5 cannot drive at all. magent does not interview the patient."
      },
      "lifting": {
       "type": "integer",
       "description": "Caller-assigned Vernon 1991 NDI lifting (integer 0-5): 0 can lift heavy weights without extra pain through 5 cannot lift or carry anything. magent does not interview the patient."
      },
      "reading": {
       "type": "integer",
       "description": "Caller-assigned Vernon 1991 NDI reading (integer 0-5): 0 can read as much as wanted with no neck pain through 5 cannot read at all. magent does not interview the patient."
      },
      "sleeping": {
       "type": "integer",
       "description": "Caller-assigned Vernon 1991 NDI sleeping (integer 0-5): 0 no trouble sleeping through 5 sleep completely disturbed (5-7 hours sleepless). magent does not interview the patient."
      },
      "headaches": {
       "type": "integer",
       "description": "Caller-assigned Vernon 1991 NDI headaches (integer 0-5): 0 no headaches through 5 headaches almost all the time. magent does not interview the patient."
      },
      "recreation": {
       "type": "integer",
       "description": "Caller-assigned Vernon 1991 NDI recreation (integer 0-5): 0 can engage in all recreation activities with no neck pain through 5 cannot do any recreation activities. magent d
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/magent-ndi-calculator-vernon-1991-ea0375c5/health.json
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