# CANRISK Canadian diabetes risk score

CANRISK

Status: LIVE
Price: $0.005 USDC
`GET /api/calc/canrisk`
HTML: https://magentlab.com/docs/canrisk
Markdown: https://magentlab.com/docs/canrisk.md

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

## What it computes

Sum the Robinson 2011 Table 3 paper-based CANRISK (pCANRISK) integer points and return the published screening thresholds at scores 21, 29, 32, 33, and 43.

## When to use

When an agent needs the published pCANRISK point total and must not invent a type 2 diabetes diagnosis, eCANRISK logistic betas, FINDRISC, or AUSDRISK.

## When not to use

- Not a medical device. magent does not diagnose type 2 diabetes or assay glucose.
- Robinson 2011 Table 3 pCANRISK integer points only. Not eCANRISK logistic betas. Not FINDRISC. Not AUSDRISK.
- Published screening thresholds are score ≥21, ≥29, ≥32 (balanced), ≥33, and ≥43 (Table 5 / Figure 4). They overlap; they are not exclusive risk bins and not a diabetes diagnosis.
- Ethnicity is caller-assigned using the paper's terms (White, Aboriginal, Black, East Asian, South Asian, Latin American, Other). magent does not assign ethnicity. Table 3 assigned no pCANRISK points to Latin American or Other (statistically insignificant); those tokens score 0.
- Family history is the count of first-degree relative categories (mother, father, sibling, child), 2 points each, not second-degree relatives. Macrosomia is a birth ≥4.1 kg and is N/A (0) for male. BMI is caller-supplied kg/m^2. Max 81 female / 86 male. Female waist 80-88 cm scores 4, so a 40-year-old White woman with BMI 22 and waist 80 cm scores 4, not 0.

## Formula

```
pCANRISK = age + sex + bmi + waist + inactivity + no_daily_fruit_veg + high_bp + high_glucose + macrosomia + family_history + ethnicity + education; age <45 -> 0, 45-54 -> 7, 55-64 -> 13, >=65 -> 15; male 6; BMI <25 -> 0, 25-29.9 -> 4, 30-34.9 -> 9, >=35 -> 14; waist men <94 -> 0, 94-102 -> 4, >102 -> 6; women <80 -> 0, 80-88 -> 4, >88 -> 6; inactivity 1; no daily fruit/veg 2; high_bp 4; high_glucose 14; macrosomia women 1 else N/A 0; family_history_count 0-4 first-degree categories * 2; ethnicity white 0 aboriginal 3 black 5 east_asian 10 south_asian 11 latin_american 0 other 0 (caller-assigned; Table 3 assigned no pCANRISK points to Latin American or Other); education less_than_high_school 5 high_school 1 some_college or university 0; max 81 female / 86 male; Robinson 2011 Table 3 pCANRISK not eCANRISK; published cutoffs score>=21 29 32 33 43
```

## Citation

[Validating the CANRISK prognostic model for assessing diabetes risk in Canada's multi-ethnic population](https://doi.org/10.24095/hpcdp.32.1.04)
Robinson CA, Agarwal G, Nerenberg K
Chronic Dis Inj Can. 2011;32(1):19-31
DOI: [10.24095/hpcdp.32.1.04](https://doi.org/10.24095/hpcdp.32.1.04)

## Worked example

### 40-year-old White woman, BMI 22, waist 80 cm

Given: `activity_30min=true, age=40, bmi_kg_m2=22, daily_fruit_veg=true, education=university, ethnicity=white, family_history_count=0, high_bp=false, high_glucose=false, macrosomia=false, sex=female, waist_cm=80`

1. Age 40 (19-44) → 0; female → 0; BMI 22 <25 → 0; female waist 80 (80-88) → 4
2. Daily 30 min activity → 0; daily fruit/vegetables → 0; no high BP → 0; no high glucose → 0; no macrosomia → 0; family count 0 → 0; White → 0; university → 0
3. Score = 4 (published max 81 female); all Table 5 cutoffs false. Not a diagnosis.


### Paper example: 58-year-old White man, one first-degree relative

Given: `activity_30min=true, age=58, bmi_kg_m2=22, daily_fruit_veg=true, education=university, ethnicity=white, family_history_count=1, high_bp=false, high_glucose=false, macrosomia=false, sex=male, waist_cm=80`

1. Age 58 (55-64) → 13; male → 6; one first-degree category → 2; remaining items 0
2. Score = 21; score_ge_21 true (Table 5 slightly elevated). Not a diagnosis.


### Balanced cutoff 32 (age ≥65, high glucose, inactivity, no daily fruit/veg)

Given: `activity_30min=false, age=65, bmi_kg_m2=22, daily_fruit_veg=false, education=university, ethnicity=white, family_history_count=0, high_bp=false, high_glucose=true, macrosomia=false, sex=female, waist_cm=79`

1. Age 65 → 15; high_glucose → 14; inactivity → 1; no daily fruit/veg → 2; female waist 79 <80 → 0
2. Score = 32; score_ge_32 true (Table 5 balanced cutoff). Not a diagnosis.


## Also searched as

- CANRISK
- pCANRISK
- Canadian diabetes risk
- Robinson CANRISK
- Canadian Diabetes Risk Assessment Questionnaire
- paper-based CANRISK

## Parameters

- `age` (integer, required): Age in years (18-120). Robinson 2011 Table 3 pCANRISK: 19-44 scores 0; magent scores 18-44 as 0. 45-54 scores 7; 55-64 scores 13; 65-78 scores 15; magent scores ≥65 as 15. Age 44 scores 0; 45 and 54 score 7; 55 and 64 score 13; 65 scores 15.
- `sex` (string, required): female or male. Robinson 2011 Table 3: female scores 0; male scores 6. Selects the sex-specific waist bands. Macrosomia is N/A for male (0).
- `bmi_kg_m2` (number, required): Body-mass index in kg/m^2 (10-80). Caller-supplied; magent does not compute BMI from height and weight. Robinson 2011 Table 3: <25 scores 0; 25-29.9 scores 4; 30-34.9 scores 9; ≥35 scores 14. 25.0 and 29.9 score 4; 30.0 and 34.9 score 9; 35.0 scores 14.
- `waist_cm` (number, required): Waist circumference in cm (40-200). Robinson 2011 Table 3 men: <94 scores 0; 94-102 scores 4; >102 scores 6. Women: <80 scores 0; 80-88 scores 4; >88 scores 6. 94 and 102 (men) and 80 and 88 (women) score 4.
- `activity_30min` (boolean, required): Usually at least 30 minutes of physical activity daily (Robinson 2011 Table 3). true scores 0; false scores 1. Caller-assigned; magent does not measure activity.
- `daily_fruit_veg` (boolean, required): Eats fruit or vegetables every day (Robinson 2011 Table 3). true scores 0; false scores 2.
- `high_bp` (boolean, required): History of high blood pressure (Robinson 2011 Table 3). true scores 4; false scores 0. magent does not measure blood pressure.
- `high_glucose` (boolean, required): History of high blood glucose (Robinson 2011 Table 3). Caller-assigned; magent does not assay glucose. true scores 14; false scores 0.
- `macrosomia` (boolean, required): Gave birth to a baby weighing 4.1 kg or more (Robinson 2011 Table 3 macrosomia, women). true scores 1 for female; false or male (N/A) scores 0.
- `family_history_count` (integer, required): Count of first-degree relative categories with diabetes: mother, father, sibling, child (Robinson 2011 Table 3 footnote g). Integer 0-4. Each category scores 2 (0, 2, 4, 6, or 8). Not second-degree relatives. magent does not take named relatives.
- `ethnicity` (string, required): Caller-assigned ethnicity using Robinson 2011 Table 3 terms. white scores 0; aboriginal 3; black 5; east_asian 10; south_asian 11. latin_american and other score 0 (Table 3 assigned no pCANRISK points; both were statistically insignificant). magent does not assign ethnicity.
- `education` (string, required): Highest education completed (Robinson 2011 Table 3). less_than_high_school scores 5; high_school scores 1; some_college or university scores 0.

## 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/canrisk`
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": [
    {
      "activity_30min": "true",
      "age": "40",
      "bmi_kg_m2": "22",
      "daily_fruit_veg": "true",
      "education": "university",
      "ethnicity": "white",
      "family_history_count": "0",
      "high_bp": "false",
      "high_glucose": "false",
      "macrosomia": "false",
      "sex": "female",
      "waist_cm": "80"
    },
    {
      "activity_30min": "true",
      "age": "40",
      "bmi_kg_m2": "22",
      "daily_fruit_veg": "true",
      "education": "university",
      "ethnicity": "white",
      "family_history_count": "0",
      "high_bp": "false",
      "high_glucose": "false",
      "macrosomia": "false",
      "sex": "female",
      "waist_cm": "80"
    }
  ]
}
```

Human paywall (two-item fixture): https://api.magentlab.com/paywall/bulk/canrisk

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/canrisk",
  "items": [
    {
      "components": [
        {
          "value": 40,
          "factor": "age",
          "points": 0,
          "present": false
        },
        {
          "value": "female",
          "factor": "sex",
          "points": 0,
          "present": false
        },
        {
          "value": 22.0,
          "factor": "bmi",
          "points": 0,
          "present": false
        },
        {
          "value": 80.0,
          "factor": "waist",
          "points": 4,
          "present": true
        },
        {
          "factor": "inactivity",
          "points": 0,
          "present": false
        },
        {
          "factor": "no_daily_fruit_veg",
          "points": 0,
          "present": false
        },
        {
          "factor": "high_bp",
          "points": 0,
          "present": false
        },
        {
          "factor": "high_glucose",
          "points": 0,
          "present": false
        },
        {
          "factor": "macrosomia",
          "points": 0,
          "present": false
        },
        {
          "value": 0,
          "factor": "family_history",
          "points": 0,
          "present": false
        },
        {
          "value": "white",
          "factor": "ethnicity",
          "points": 0,
          "present": false
        },
        {
          "value": "university",
          "factor": "education",
          "points": 0,
          "present": false
        }
      ],
      "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": "Robinson CA, Agarwal G, Nerenberg K",
        "doi": "10.24095/hpcdp.32.1.04",
        "id": "robinson-2011-canrisk",
        "pmid": "22153173",
        "source": "Chronic Dis Inj Can. 2011;32(1):19-31",
        "title": "Validating the CANRISK prognostic model for assessing diabetes risk in Canada's multi-ethnic population"
      },
      "formula": "canrisk",
      "formula_expression": "pCANRISK = age + sex + bmi + waist + inactivity + no_daily_fruit_veg + high_bp + high_glucose + macrosomia + family_history + ethnicity + education; age <45 -> 0, 45-54 -> 7, 55-64 -> 13, >=65 -> 15; male 6; BMI <25 -> 0, 25-29.9 -> 4, 30-34.9 -> 9, >=35 -> 14; waist men <94 -> 0, 94-102 -> 4, >102 -> 6; women <80 -> 0, 80-88 -> 4, >88 -> 6; inactivity 1; no daily fruit/veg 2; high_bp 4; high_glucose 14; macrosomia women 1 else N/A 0; family_history_count 0-4 first-degree categories * 2; ethnicity white 0 aboriginal 3 black 5 east_asian 10 south_asian 11 latin_american 0 other 0 (caller-assigned; Table 3 assigned no pCANRISK points to Latin American or Other); education less_than_high_school 5 high_school 1 some_college or university 0; max 81 female / 86 male; Robinson 2011 Table 3 pCANRISK not eCANRISK; published cutoffs score>=21 29 32 33 43",
      "max_score": 81,
      "score": 4,
      "age_years": 40,
      "sex": "female",
      "bmi_kg_m2": 22.0,
      "waist_cm": 80.0,
      "education": "university",
      "ethnicity": "white",
      "family_history_count": 0,
      "score_ge_21": false,
      "score_ge_29": false,
      "score_ge_32": false,
      "score_ge_33": false,
      "score_ge_43": false
    },
    {
      "components": [
        {
          "value": 40,
          "factor": "age",
          "points": 0,
          "present": false
        },
        {
          "value": "female",
          "factor": "sex",
          "points": 0,
          "present": false
        },
        {
          "value": 22.0,
          "factor": "bmi",
          "points": 0,
          "present": false
        },
        {
          "value": 80.0,
          "factor": "waist",
          "points": 4,
          "present": true
        },
        {
          "factor": "inactivity",
          "points": 0,
          "present": false
        },
        {
          "factor": "no_daily_fruit_veg",
          "points": 0,
          "present": false
        },
        {
          "factor": "high_bp",
          "points": 0,
          "present": false
        },
        {
          "factor": "high_glucose",
          "points": 0,
          "present": false
        },
        {
          "factor": "macrosomia",
          "points": 0,
          "present": false
        },
        {
          "value": 0,
          "factor": "family_history",
          "points": 0,
          "present": false
        },
        {
          "value": "white",
          "factor": "ethnicity",
          "points": 0,
          "present": false
        },
        {
          "value": "university",
          "factor": "education",
          "points": 0,
          "present": false
        }
      ],
      "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": "Robinson CA, Agarwal G, Nerenberg K",
        "doi": "10.24095/hpcdp.32.1.04",
        "id": "robinson-2011-canrisk",
        "pmid": "22153173",
        "source": "Chronic Dis Inj Can. 2011;32(1):19-31",
        "title": "Validating the CANRISK prognostic model for assessing diabetes risk in Canada's multi-ethnic population"
      },
      "formula": "canrisk",
      "formula_expression": "pCANRISK = age + sex + bmi + waist + inactivity + no_daily_fruit_veg + high_bp + high_glucose + macrosomia + family_history + ethnicity + education; age <45 -> 0, 45-54 -> 7, 55-64 -> 13, >=65 -> 15; male 6; BMI <25 -> 0, 25-29.9 -> 4, 30-34.9 -> 9, >=35 -> 14; waist men <94 -> 0, 94-102 -> 4, >102 -> 6; women <80 -> 0, 80-88 -> 4, >88 -> 6; inactivity 1; no daily fruit/veg 2; high_bp 4; high_glucose 14; macrosomia women 1 else N/A 0; family_history_count 0-4 first-degree categories * 2; ethnicity white 0 aboriginal 3 black 5 east_asian 10 south_asian 11 latin_american 0 other 0 (caller-assigned; Table 3 assigned no pCANRISK points to Latin American or Other); education less_than_high_school 5 high_school 1 some_college or university 0; max 81 female / 86 male; Robinson 2011 Table 3 pCANRISK not eCANRISK; published cutoffs score>=21 29 32 33 43",
      "max_score": 81,
      "score": 4,
      "age_years": 40,
      "sex": "female",
      "bmi_kg_m2": 22.0,
      "waist_cm": 80.0,
      "education": "university",
      "ethnicity": "white",
      "family_history_count": 0,
      "score_ge_21": false,
      "score_ge_29": false,
      "score_ge_32": false,
      "score_ge_33": false,
      "score_ge_43": false
    }
  ]
}
```

## Response fields

- `formula` (string): canrisk
- `formula_expression` (string): Exact Robinson 2011 Table 3 pCANRISK expression
- `score` (integer): pCANRISK points; published maxima 81 female / 86 male
- `max_score` (integer): 81 if female, 86 if male (Robinson 2011 published maxima)
- `score_ge_21` (boolean): true iff score ≥21 (Table 5 / Figure 4 slightly elevated vs FINDRISC). Screening threshold, not an exclusive band and not a diabetes diagnosis.
- `score_ge_29` (boolean): true iff score ≥29 (Table 5 / Figure 4 moderate vs FINDRISC). Screening threshold, not an exclusive band.
- `score_ge_32` (boolean): true iff score ≥32 (Table 5 balanced / optimal cutoff). Screening threshold, not a diabetes diagnosis.
- `score_ge_33` (boolean): true iff score ≥33 (Table 5 / Figure 4 high vs FINDRISC). Screening threshold, not an exclusive band.
- `score_ge_43` (boolean): true iff score ≥43 (Table 5 / Figure 4 very high vs FINDRISC). Screening threshold, not an exclusive band.
- `age_years` (integer): Age in years used for the age band
- `sex` (string): female or male, used for sex points and waist
- `bmi_kg_m2` (number): Caller-supplied BMI in kg/m^2 used for the BMI band
- `waist_cm` (number): Waist circumference in cm used
- `ethnicity` (string): white, aboriginal, black, east_asian, south_asian, latin_american, or other
- `education` (string): less_than_high_school, high_school, some_college, or university
- `family_history_count` (integer): Count of first-degree relative categories (0-4) used
- `components` (array): Per-factor points
- `citation` (object): Robinson 2011 Chronic Diseases and Injuries in Canada citation
- `disclaimer` (string): Not-a-device notice

## Example JSON

Frozen fixture. Not a live lookup.

```json
{
  "components": [
    {
      "value": 40,
      "factor": "age",
      "points": 0,
      "present": false
    },
    {
      "value": "female",
      "factor": "sex",
      "points": 0,
      "present": false
    },
    {
      "value": 22.0,
      "factor": "bmi",
      "points": 0,
      "present": false
    },
    {
      "value": 80.0,
      "factor": "waist",
      "points": 4,
      "present": true
    },
    {
      "factor": "inactivity",
      "points": 0,
      "present": false
    },
    {
      "factor": "no_daily_fruit_veg",
      "points": 0,
      "present": false
    },
    {
      "factor": "high_bp",
      "points": 0,
      "present": false
    },
    {
      "factor": "high_glucose",
      "points": 0,
      "present": false
    },
    {
      "factor": "macrosomia",
      "points": 0,
      "present": false
    },
    {
      "value": 0,
      "factor": "family_history",
      "points": 0,
      "present": false
    },
    {
      "value": "white",
      "factor": "ethnicity",
      "points": 0,
      "present": false
    },
    {
      "value": "university",
      "factor": "education",
      "points": 0,
      "present": false
    }
  ],
  "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": "Robinson CA, Agarwal G, Nerenberg K",
    "doi": "10.24095/hpcdp.32.1.04",
    "id": "robinson-2011-canrisk",
    "pmid": "22153173",
    "source": "Chronic Dis Inj Can. 2011;32(1):19-31",
    "title": "Validating the CANRISK prognostic model for assessing diabetes risk in Canada's multi-ethnic population"
  },
  "formula": "canrisk",
  "formula_expression": "pCANRISK = age + sex + bmi + waist + inactivity + no_daily_fruit_veg + high_bp + high_glucose + macrosomia + family_history + ethnicity + education; age <45 -> 0, 45-54 -> 7, 55-64 -> 13, >=65 -> 15; male 6; BMI <25 -> 0, 25-29.9 -> 4, 30-34.9 -> 9, >=35 -> 14; waist men <94 -> 0, 94-102 -> 4, >102 -> 6; women <80 -> 0, 80-88 -> 4, >88 -> 6; inactivity 1; no daily fruit/veg 2; high_bp 4; high_glucose 14; macrosomia women 1 else N/A 0; family_history_count 0-4 first-degree categories * 2; ethnicity white 0 aboriginal 3 black 5 east_asian 10 south_asian 11 latin_american 0 other 0 (caller-assigned; Table 3 assigned no pCANRISK points to Latin American or Other); education less_than_high_school 5 high_school 1 some_college or university 0; max 81 female / 86 male; Robinson 2011 Table 3 pCANRISK not eCANRISK; published cutoffs score>=21 29 32 33 43",
  "max_score": 81,
  "score": 4,
  "age_years": 40,
  "sex": "female",
  "bmi_kg_m2": 22.0,
  "waist_cm": 80.0,
  "education": "university",
  "ethnicity": "white",
  "family_history_count": 0,
  "score_ge_21": false,
  "score_ge_29": false,
  "score_ge_32": false,
  "score_ge_33": false,
  "score_ge_43": false
}
```

## Errors

- HTTP 400 `invalid_age`: age must be an integer from 18 to 120 Returned before settlement; you are not charged.
- HTTP 400 `invalid_sex`: sex must be female or male 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_canrisk`: CANRISK inputs must match Robinson 2011 pCANRISK age, sex, BMI, waist, activity, diet, BP, glucose, macrosomia, family history, ethnicity, and education. 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

- [FINDRISC](https://magentlab.com/docs/findrisc) — Sum the original Lindström 2003 seven-item Finnish diabetes risk score (FINDRISC, 0–20) and return at_risk when the total is ≥9.
- [AUSDRISK](https://magentlab.com/docs/ausdrisk) — Sum the Chen 2010 AUSDRISK Box 3 questionnaire points (waist model) and return at_risk when the total is ≥12.
- [Bang diabetes screening](https://magentlab.com/docs/ada-diabetes) — Sum the Bang 2009 Table 2 development screening score for undiagnosed diabetes and return high_risk when the total is ≥5.
- [Cambridge diabetes](https://magentlab.com/docs/cambridge-diabetes) — Compute the Griffin 2000 Cambridge logistic probability of undetected type 2 diabetes from age, sex, BMI, prescribed antihypertensive medication, prescribed steroids, first-degree family history, and smoking.

## 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.