# Rome IV child cyclic vomiting

Rome IV Child CVS

Status: LIVE
Price: $0.005 USDC
`GET /api/calc/rome_iv_child_cvs`
HTML: https://magentlab.com/docs/rome-iv-child-cvs
Markdown: https://magentlab.com/docs/rome-iv-child-cvs.md

Not a medical device. Not a diagnosis, dose, or listing recommendation.

## What it computes

Apply the Hyams 2016 Rome IV H1a child/adolescent cyclic vomiting syndrome diagnostic criteria and return whether the published child CVS box holds (rome_iv_child_cvs).

## When to use

When an agent already has the four caller-assigned Hyams 2016 Rome IV H1a child/adolescent cyclic vomiting flags and needs whether the published child CVS box holds. magent does not examine the child.

## When not to use

- Not a medical device.
- Not a diagnosis. magent does not diagnose cyclic vomiting syndrome.
- The caller assigns the four flags. magent does not examine the child.
- This tool is Hyams 2016 Rome IV H1a child/adolescent cyclic vomiting syndrome only. Not neonate/toddler G3. Not adult Rome IV CVS (Stanghellini 2016 B3b). Not cannabinoid hyperemesis. History of migraine is not a required H1a flag and is not parsed. If abdominal pain predominates, consider abdominal migraine; that note is not a parsed flag.

## Formula

```
rome_iv_child_cvs iff two_or_more_periods_intense_nausea_paroxysmal_vomiting_hours_to_days_within_6_months and episodes_stereotypical and episodes_separated_weeks_to_months_with_return_to_baseline and not_attributed_to_another_condition (Hyams 2016 Rome IV H1a Cyclic Vomiting Syndrome)
```

## Citation

[Childhood Functional Gastrointestinal Disorders: Child/Adolescent](https://doi.org/10.1053/j.gastro.2016.02.015)
Hyams JS, Di Lorenzo C, Saps M, Shulman RJ, Staiano A, van Tilburg M
Gastroenterology. 2016;150(6):1456-1468
DOI: [10.1053/j.gastro.2016.02.015](https://doi.org/10.1053/j.gastro.2016.02.015)

## Worked example

### All four required flags

Given: `episodes_separated_weeks_to_months_with_return_to_baseline=true, episodes_stereotypical=true, not_attributed_to_another_condition=true, two_or_more_periods_intense_nausea_paroxysmal_vomiting_hours_to_days_within_6_months=true`

1. Two or more periods of intense nausea and paroxysmal vomiting lasting hours to days within 6 months is true
2. Episodes are stereotypical is true
3. Episodes separated by weeks to months with return to baseline is true
4. Not attributed to another condition is true
5. rome_iv_child_cvs is true


### Three flags without not attributed to another condition

Given: `episodes_separated_weeks_to_months_with_return_to_baseline=true, episodes_stereotypical=true, not_attributed_to_another_condition=false, two_or_more_periods_intense_nausea_paroxysmal_vomiting_hours_to_days_within_6_months=true`

1. Two or more periods of intense nausea and paroxysmal vomiting lasting hours to days within 6 months is true
2. Episodes are stereotypical is true
3. Episodes separated by weeks to months with return to baseline is true
4. Not attributed to another condition is false
5. rome_iv_child_cvs is false


## Also searched as

- Rome IV child cyclic vomiting
- Hyams 2016 cyclic vomiting
- Rome IV H1a
- child adolescent cyclic vomiting
- pediatric cyclic vomiting Rome IV
- Hyams H1a CVS
- Rome IV child CVS
- cyclic vomiting syndrome child

## Parameters

- `two_or_more_periods_intense_nausea_paroxysmal_vomiting_hours_to_days_within_6_months` (boolean, required): Two or more periods of intense, unremitting nausea and paroxysmal vomiting lasting hours to days within a 6-month period, as assigned (Hyams 2016 Rome IV H1a). true or false as assigned by the caller. magent does not examine the child.
- `episodes_stereotypical` (boolean, required): Episodes are stereotypical in each patient, as assigned (Hyams 2016 Rome IV H1a). true or false as assigned by the caller. magent does not examine the child.
- `episodes_separated_weeks_to_months_with_return_to_baseline` (boolean, required): Episodes are separated by weeks to months with return to baseline health between episodes, as assigned (Hyams 2016 Rome IV H1a). true or false as assigned by the caller. magent does not examine the child.
- `not_attributed_to_another_condition` (boolean, required): After appropriate medical evaluation, the symptoms cannot be attributed to another condition, as assigned (Hyams 2016 Rome IV H1a). true or false as assigned by the caller. magent does not examine the child.

## Bulk (POST)

POST the same path with a JSON items array. The first item is the GET unit; each additional item is $0.002. Invalid items return HTTP 400 before settlement.

Method: `POST /api/calc/rome_iv_child_cvs`
Max items: 25
Price: unit_amount + extra_item_amount * (n - 1) (unit 5000 atomic, extra 2000 atomic)
Status: PREVIEW

- 1 to 25 items. Each item uses the same keys as the GET query parameters.
- POST of 1 item costs the same as GET. Lists longer than 25: chunk into multiple POSTs. Extra items still execute; do not pad dummy rows.
- The first invalid item fails the whole request (index in the 400 JSON). You are not charged.
- HTTP 200 is {count, path, items}. Each items[i] is the GET 200 body for that row.
- Catalog misses (empty matches, found=false) stay paid 200s inside that slot.
- x402 resource URL is this path plus n and body_sha256. Browsers that prefer text/html get the same paywall as GET; Pay retries POST with the same items.

Example request:

```json
{
  "items": [
    {
      "episodes_separated_weeks_to_months_with_return_to_baseline": "true",
      "episodes_stereotypical": "true",
      "not_attributed_to_another_condition": "true",
      "two_or_more_periods_intense_nausea_paroxysmal_vomiting_hours_to_days_within_6_months": "true"
    },
    {
      "episodes_separated_weeks_to_months_with_return_to_baseline": "true",
      "episodes_stereotypical": "true",
      "not_attributed_to_another_condition": "true",
      "two_or_more_periods_intense_nausea_paroxysmal_vomiting_hours_to_days_within_6_months": "true"
    }
  ]
}
```

Human paywall (two-item fixture): https://api.magentlab.com/paywall/bulk/rome-iv-child-cvs

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/rome_iv_child_cvs",
  "items": [
    {
      "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.",
      "citation": {
        "authors": "Hyams JS, Di Lorenzo C, Saps M, Shulman RJ, Staiano A, van Tilburg M",
        "doi": "10.1053/j.gastro.2016.02.015",
        "id": "hyams-2016",
        "pmid": "27144632",
        "source": "Gastroenterology. 2016;150(6):1456-1468",
        "title": "Childhood Functional Gastrointestinal Disorders: Child/Adolescent"
      },
      "formula": "rome_iv_child_cvs",
      "formula_expression": "rome_iv_child_cvs iff two_or_more_periods_intense_nausea_paroxysmal_vomiting_hours_to_days_within_6_months and episodes_stereotypical and episodes_separated_weeks_to_months_with_return_to_baseline and not_attributed_to_another_condition (Hyams 2016 Rome IV H1a Cyclic Vomiting Syndrome)",
      "criteria": [
        {
          "factor": "two_or_more_periods_intense_nausea_paroxysmal_vomiting_hours_to_days_within_6_months",
          "met": true
        },
        {
          "factor": "episodes_stereotypical",
          "met": true
        },
        {
          "factor": "episodes_separated_weeks_to_months_with_return_to_baseline",
          "met": true
        },
        {
          "factor": "not_attributed_to_another_condition",
          "met": true
        }
      ],
      "rome_iv_child_cvs": true
    },
    {
      "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.",
      "citation": {
        "authors": "Hyams JS, Di Lorenzo C, Saps M, Shulman RJ, Staiano A, van Tilburg M",
        "doi": "10.1053/j.gastro.2016.02.015",
        "id": "hyams-2016",
        "pmid": "27144632",
        "source": "Gastroenterology. 2016;150(6):1456-1468",
        "title": "Childhood Functional Gastrointestinal Disorders: Child/Adolescent"
      },
      "formula": "rome_iv_child_cvs",
      "formula_expression": "rome_iv_child_cvs iff two_or_more_periods_intense_nausea_paroxysmal_vomiting_hours_to_days_within_6_months and episodes_stereotypical and episodes_separated_weeks_to_months_with_return_to_baseline and not_attributed_to_another_condition (Hyams 2016 Rome IV H1a Cyclic Vomiting Syndrome)",
      "criteria": [
        {
          "factor": "two_or_more_periods_intense_nausea_paroxysmal_vomiting_hours_to_days_within_6_months",
          "met": true
        },
        {
          "factor": "episodes_stereotypical",
          "met": true
        },
        {
          "factor": "episodes_separated_weeks_to_months_with_return_to_baseline",
          "met": true
        },
        {
          "factor": "not_attributed_to_another_condition",
          "met": true
        }
      ],
      "rome_iv_child_cvs": true
    }
  ]
}
```

## Response fields

- `formula` (string): rome_iv_child_cvs
- `formula_expression` (string): Hyams 2016 Rome IV H1a child/adolescent cyclic vomiting: two or more periods of intense nausea and paroxysmal vomiting lasting hours to days within 6 months, stereotypical episodes, weeks-to-months separation with return to baseline, and not attributed to another condition
- `rome_iv_child_cvs` (boolean): true only when all four required flags hold. Not a diagnosis.
- `criteria` (array): Per-factor rows with factor and met for the four required flags
- `citation` (object): Hyams 2016 Gastroenterology citation
- `disclaimer` (string): Not-a-device notice

## Example JSON

Frozen fixture. Not a live lookup.

```json
{
  "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.",
  "citation": {
    "authors": "Hyams JS, Di Lorenzo C, Saps M, Shulman RJ, Staiano A, van Tilburg M",
    "doi": "10.1053/j.gastro.2016.02.015",
    "id": "hyams-2016",
    "pmid": "27144632",
    "source": "Gastroenterology. 2016;150(6):1456-1468",
    "title": "Childhood Functional Gastrointestinal Disorders: Child/Adolescent"
  },
  "formula": "rome_iv_child_cvs",
  "formula_expression": "rome_iv_child_cvs iff two_or_more_periods_intense_nausea_paroxysmal_vomiting_hours_to_days_within_6_months and episodes_stereotypical and episodes_separated_weeks_to_months_with_return_to_baseline and not_attributed_to_another_condition (Hyams 2016 Rome IV H1a Cyclic Vomiting Syndrome)",
  "criteria": [
    {
      "factor": "two_or_more_periods_intense_nausea_paroxysmal_vomiting_hours_to_days_within_6_months",
      "met": true
    },
    {
      "factor": "episodes_stereotypical",
      "met": true
    },
    {
      "factor": "episodes_separated_weeks_to_months_with_return_to_baseline",
      "met": true
    },
    {
      "factor": "not_attributed_to_another_condition",
      "met": true
    }
  ],
  "rome_iv_child_cvs": true
}
```

## Errors

- HTTP 400 `invalid_rome_iv_child_cvs`: Rome IV child cyclic vomiting needs the Hyams 2016 child/adolescent H1a flags. Returned before settlement; you are not charged.
- HTTP 400 `invalid_flag`: boolean clinical flags must be true or false Returned before settlement; you are not charged.
- HTTP 400 `invalid_items`: POST body must be a JSON object with only an items array Returned before settlement; you are not charged.
- HTTP 400 `invalid_item_count`: items must be an array of 1 to 25 objects Returned before settlement; you are not charged.
- HTTP 400 `invalid_item`: each items entry must be a JSON object Returned before settlement; you are not charged.

Shared HTTP 402 and 503: https://magentlab.com/docs/payments

## Related tools

- [Rome IV CVS](https://magentlab.com/docs/rome-iv-cvs) — Apply the Stanghellini 2016 Rome IV adult cyclic vomiting syndrome B3b diagnostic criteria and return whether the published CVS box holds (rome_iv_cvs) plus the supportive migraine_history flag.
- [Rome IV Child Rumination](https://magentlab.com/docs/rome-iv-child-rumination) — Apply the Hyams 2016 Rome IV H1c child/adolescent rumination syndrome diagnostic criteria and return whether the published rumination box holds (rome_iv_child_rumination).

## Payment

Unpaid requests return HTTP 402 even if query parameters or POST items are missing or invalid, so CDP and agents can index the path. After a PAYMENT-SIGNATURE, invalid params return HTTP 400 JSON before settlement. magent does not charge. Fix the params, then request a new 402 quote for that complete URL. Catalog misses (empty matches, found=false) are valid paid 200s.

- GET the tool with Accept: application/json (do not send Accept: text/html unless you want the human paywall).
- HTTP 402 means you have not paid. Decode the base64 PAYMENT-REQUIRED header. HTTP 503 is not a new quote.
- Sign accepts[0] (exact, EIP-3009) with validBefore = now + maxTimeoutSeconds (600 seconds), or accepts[1] (batch-settlement deposit/voucher) on product GET. Ping and POST {items} stay exact. Magent retries transient facilitator 429/5xx before answering.
- Retry the same URL with PAYMENT-SIGNATURE (base64 JSON of accepted and payload). Magent attaches canonical extensions.bazaar on CDP verify/settle; echoing 402 bazaar is optional.
- Success is HTTP 200 JSON plus PAYMENT-RESPONSE. exact settles before the tool. batch-settlement verifies (and deposit-settles) before the tool and commits the charge after HTTP 2xx. HTTP 503: retry the same PAYMENT-SIGNATURE. Mint a new exact nonce only after a new HTTP 402.

- offered `exact` on eip155:8453: Fixed-price USDC on Base. The buyer authorizes the advertised amount (EIP-3009). magent settles before the tool runs (paymentFlow upfront). extra.assetTransferMethod=eip3009 extra.paymentFlow=upfront.
- offered `batch-settlement` on eip155:8453: Payment-channel vouchers claimed later in batches. Exact stays accepts[0]. Same-path POST {items} is still exact. extra.assetTransferMethod=eip3009 extra.paymentFlow=authorization.

- not offered `upto`: Not offered. Usage-based: buyer authorizes a ceiling, seller settles the actual amount after work. Reserved for a future metered tool. Not for current calculators or code search.

Same-path POST {items} is still scheme exact: one EIP-3009 authorization for GET unit plus $0.002 per extra item. That is not x402 batch-settlement (payment channels / vouchers).

Shared HTTP 402 and 503 table: https://magentlab.com/docs/payments

Stdio MCP (one process per host): https://magentlab.com/docs/mcp

## Guarantees

- HTTP 402 is unpaid, including a missing query. After PAYMENT-SIGNATURE, invalid parameters return HTTP 400 before settlement. You are not charged. HTTP 402 never includes the tool JSON.
- exact: settlement finishes before the tool (paymentFlow upfront). batch-settlement: verify/deposit before the tool; chargedCumulativeAmount commits after HTTP 2xx. Uncertain or failed settlement fails closed (HTTP 503). Retry the same PAYMENT-SIGNATURE.
- HTTP 402 is unpaid only. Do not sign a second authorization because of a 503.
- Execution is timeout-bounded and concurrency-capped.
- Calculator inputs are stored encrypted for allowlisted operators (Magent Console). They are not in public logs, SSH lookups, catalog, or rollups. Request logs store path without query.