# magent (full)

magent is pay-per-request clinical ground truth for autonomous medical agents. USDC on Base via x402 V2. No API keys.
Distinct from npm `@x402/fetch` (a payment fetch wrapper). Call this API with that wrapper.

Site: https://magentlab.com
API: https://api.magentlab.com
Manifest: GET https://api.magentlab.com/.well-known/x402
Catalog: GET https://api.magentlab.com/v1/catalog
OpenAPI: GET https://api.magentlab.com/openapi.json
Short onboarding: GET https://api.magentlab.com/llms.txt

## Pay (x402 V2)

1. GET the tool with `Accept: application/json`.
2. HTTP 402. Decode the base64 `PAYMENT-REQUIRED` header.
3. Retry the same URL with `PAYMENT-SIGNATURE` (base64 JSON echoing `accepted`, `payload`, and `extensions` when present).
4. Success is HTTP 200 JSON plus `PAYMENT-RESPONSE`. Settlement happens before the tool runs.

## Cursor mcp.json

{
  "mcpServers": {
    "magent": {
      "args": [
        "-y",
        "@magent/mcp"
      ],
      "command": "npx",
      "env": {
        "X402_PRIVATE_KEY": "0xYOUR_SPENDING_KEY"
      }
    }
  }
}

## @x402/fetch example

```js
import { wrapFetchWithPayment } from "@x402/fetch";
const paid = wrapFetchWithPayment(fetch, account);
const res = await paid("https://api.magentlab.com/api/ontology/translate?query=Tylenol%20500mg&system=rxnorm");
```

## Ontology translation

GET /api/ontology/translate
Price: $0.005 USDC (5000 atomic) on eip155:8453
Example: https://api.magentlab.com/api/ontology/translate?query=Tylenol%20500mg&system=rxnorm
Human docs: https://magentlab.com/docs/ontology

x402 V2 curl (expect 402 until paid):

curl -i -H "Accept: application/json" "https://api.magentlab.com/api/ontology/translate?query=Tylenol%20500mg&system=rxnorm"

- query (query, required): Natural-language drug, diagnosis, or lab description. Max 512 characters. Do not send patient names.
- system (query, optional, enum rxnorm|icd10|loinc): Restrict to rxnorm, icd10 (ICD-10-CM), or loinc. Omit to search all.
- tty (query, optional, enum SCD|SBD|IN|PIN|MIN|BN|GPCK|BPCK|DF|SCDC|SBDC|SCDF|SBDF|CM|LN): Restrict term type. Pharmacy orders typically want SCD. ICD-10-CM is CM; LOINC is LN.
- limit (query, optional, default 5): Number of ranked matches to return (1-25). Default 5.
- min_score (query, optional, default 35): Minimum rank score 0-100. Default 35.
- include_obsolete (query, optional, default false): Include deprecated/obsolete codes. Default false.
- billable_only (query, optional, default true): ICD-10-CM: return only HIPAA billable codes, not headers. Default true.

- HTTP 400 invalid_query: query is required and must be 1-512 characters
- HTTP 400 invalid_system: system must be rxnorm, icd10, or loinc
- HTTP 400 invalid_tty: tty must be a known RxNorm, ICD-10-CM, or LOINC term type
- HTTP 400 invalid_limit: limit must be an integer from 1 to 25
- HTTP 400 invalid_min_score: min_score must be an integer from 0 to 100
- HTTP 402 payment_required: Missing or invalid PAYMENT-SIGNATURE; decode the PAYMENT-REQUIRED header
- HTTP 409 payment_in_progress: The same authorization nonce is already being settled; retry shortly
- HTTP 429 rate_limited: Too many requests from this client
- HTTP 503 settlement_uncertain: Settlement is unconfirmed; retry with the same PAYMENT-SIGNATURE
- HTTP 503 facilitator_unavailable: Payment facilitator unavailable
- HTTP 503 facilitator_misconfigured: Payment facilitator is not configured
- HTTP 503 facilitator_unauthorized: Payment facilitator rejected credentials
- HTTP 503 ledger_unavailable: Payment ledger unavailable
- HTTP 503 payment_unavailable: Payment processing unavailable

Example 200 (fixture, not a live lookup):

{
  "system": "rxnorm",
  "matches": [
    {
      "code": "198440",
      "status": "current",
      "system": "rxnorm",
      "display": "acetaminophen 500 MG Oral Tablet",
      "tty": "SCD",
      "obsolete": false,
      "score": 95,
      "billable": null
    }
  ],
  "query": "Tylenol 500mg",
  "disclaimer": "Not a medical device. Deterministic published-formula or coded-ontology output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
  "catalog": {
    "coverage": "full",
    "icd10cm_fy": "FY2026-04",
    "license": {
      "icd10cm": "ICD-10-CM from CMS/NCHS. US claims codes, not WHO ICD-10.",
      "loinc": "This material contains content from LOINC (http://loinc.org). LOINC is copyright © Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee and is available at no cost under the license at http://loinc.org/license. LOINC® is a registered United States trademark of Regenstrief Institute, Inc.",
      "rxnorm": "This product uses publicly available data courtesy of the U.S. National Library of Medicine (NLM), National Institutes of Health, Department of Health and Human Services; NLM is not responsible for the product and does not endorse or recommend this or any other product."
    },
    "loinc_version": "2.82",
    "notes": "ICD-10 entries are ICD-10-CM (US claims), not WHO ICD-10. RxNorm is Current Prescribable Content until a licensed full monthly ingest lands.",
    "rxnorm_release": "2026-08-03",
    "source": "postgres ingest",
    "systems": [
      "rxnorm",
      "icd10",
      "loinc"
    ],
    "version": "icd10:FY2026-04|loinc:2.82|rxnorm:2026-08-03"
  },
  "match_count": 1,
  "match_quality": "high"
}

## Ontology lookup

GET /api/ontology/lookup
Price: $0.005 USDC (5000 atomic) on eip155:8453
Example: https://api.magentlab.com/api/ontology/lookup?system=rxnorm&code=198440
Human docs: https://magentlab.com/docs/ontology-lookup

x402 V2 curl (expect 402 until paid):

curl -i -H "Accept: application/json" "https://api.magentlab.com/api/ontology/lookup?system=rxnorm&code=198440"

- system (query, required, enum rxnorm|icd10|loinc): rxnorm, icd10 (ICD-10-CM), or loinc.
- code (query, required): Exact published identifier. ICD-10-CM accepts dotted or compact form (E11.9 or E119). Max 32 characters.

- HTTP 400 invalid_system: system must be rxnorm, icd10, or loinc
- HTTP 400 invalid_code: code is required and must be 1-32 characters
- HTTP 402 payment_required: Missing or invalid PAYMENT-SIGNATURE; decode the PAYMENT-REQUIRED header
- HTTP 409 payment_in_progress: The same authorization nonce is already being settled; retry shortly
- HTTP 429 rate_limited: Too many requests from this client
- HTTP 503 settlement_uncertain: Settlement is unconfirmed; retry with the same PAYMENT-SIGNATURE
- HTTP 503 facilitator_unavailable: Payment facilitator unavailable
- HTTP 503 facilitator_misconfigured: Payment facilitator is not configured
- HTTP 503 facilitator_unauthorized: Payment facilitator rejected credentials
- HTTP 503 ledger_unavailable: Payment ledger unavailable
- HTTP 503 payment_unavailable: Payment processing unavailable

Example 200 (fixture, not a live lookup):

{
  "code": "198440",
  "status": "current",
  "system": "rxnorm",
  "display": "acetaminophen 500 MG Oral Tablet",
  "tty": "SCD",
  "obsolete": false,
  "found": true,
  "disclaimer": "Not a medical device. Deterministic published-formula or coded-ontology output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
  "billable": null,
  "synonyms": [
    "acetaminophen 500 MG Oral Tablet",
    "APAP 500 MG Oral Tablet"
  ],
  "catalog": {
    "coverage": "full",
    "icd10cm_fy": "FY2026-04",
    "license": {
      "icd10cm": "ICD-10-CM from CMS/NCHS. US claims codes, not WHO ICD-10.",
      "loinc": "This material contains content from LOINC (http://loinc.org). LOINC is copyright © Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee and is available at no cost under the license at http://loinc.org/license. LOINC® is a registered United States trademark of Regenstrief Institute, Inc.",
      "rxnorm": "This product uses publicly available data courtesy of the U.S. National Library of Medicine (NLM), National Institutes of Health, Department of Health and Human Services; NLM is not responsible for the product and does not endorse or recommend this or any other product."
    },
    "loinc_version": "2.82",
    "notes": "ICD-10 entries are ICD-10-CM (US claims), not WHO ICD-10. RxNorm is Current Prescribable Content until a licensed full monthly ingest lands.",
    "rxnorm_release": "2026-08-03",
    "source": "postgres ingest",
    "systems": [
      "rxnorm",
      "icd10",
      "loinc"
    ],
    "version": "icd10:FY2026-04|loinc:2.82|rxnorm:2026-08-03"
  }
}

## Mosteller BSA

GET /api/calc/bsa_mosteller
Price: $0.005 USDC (5000 atomic) on eip155:8453
Example: https://api.magentlab.com/api/calc/bsa_mosteller?height_cm=170&weight_kg=70
Human docs: https://magentlab.com/docs/bsa

x402 V2 curl (expect 402 until paid):

curl -i -H "Accept: application/json" "https://api.magentlab.com/api/calc/bsa_mosteller?height_cm=170&weight_kg=70"

- height_cm (query, optional): Height in centimeters. Provide height_cm or height_in.
- weight_kg (query, optional): Weight in kilograms. Provide weight_kg or weight_lb.
- height_in (query, optional): Height in inches. Converted as cm = in * 2.54.
- weight_lb (query, optional): Weight in pounds. Converted as kg = lb * 0.45359237.

- HTTP 400 invalid_height: height_cm (50-250) or height_in (20-98) is required
- HTTP 400 invalid_weight: weight_kg (1-500) or weight_lb (2-1100) is required
- HTTP 402 payment_required: Missing or invalid PAYMENT-SIGNATURE; decode the PAYMENT-REQUIRED header
- HTTP 409 payment_in_progress: The same authorization nonce is already being settled; retry shortly
- HTTP 429 rate_limited: Too many requests from this client
- HTTP 503 settlement_uncertain: Settlement is unconfirmed; retry with the same PAYMENT-SIGNATURE
- HTTP 503 facilitator_unavailable: Payment facilitator unavailable
- HTTP 503 facilitator_misconfigured: Payment facilitator is not configured
- HTTP 503 facilitator_unauthorized: Payment facilitator rejected credentials
- HTTP 503 ledger_unavailable: Payment ledger unavailable
- HTTP 503 payment_unavailable: Payment processing unavailable

Example 200 (fixture, not a live lookup):

{
  "disclaimer": "Not a medical device. Deterministic published-formula or coded-ontology output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
  "citation": {
    "authors": "Mosteller RD",
    "doi": "10.1056/NEJM198710223171717",
    "id": "mosteller-1987",
    "source": "N Engl J Med. 1987;317(17):1098",
    "title": "Simplified calculation of body-surface area"
  },
  "formula": "mosteller",
  "formula_expression": "BSA_m2 = sqrt((height_cm * weight_kg) / 3600)",
  "weight_kg": 70.0,
  "bsa_m2": 1.8181,
  "height_cm": 170.0
}

## CKD-EPI 2021 eGFR

GET /api/calc/egfr_ckd_epi
Price: $0.005 USDC (5000 atomic) on eip155:8453
Example: https://api.magentlab.com/api/calc/egfr_ckd_epi?creatinine_mg_dl=1.1&age=65&sex=female
Human docs: https://magentlab.com/docs/egfr

x402 V2 curl (expect 402 until paid):

curl -i -H "Accept: application/json" "https://api.magentlab.com/api/calc/egfr_ckd_epi?creatinine_mg_dl=1.1&age=65&sex=female"

- creatinine_mg_dl (query, optional): Serum creatinine in mg/dL. Provide this or creatinine_umol_l.
- creatinine_umol_l (query, optional): Serum creatinine in µmol/L. Converted as mg/dL = µmol/L / 88.42.
- age (query, required): Age in years (18-120). CKD-EPI 2021 is validated in adults.
- sex (query, required, enum female|male): Sex used by the published equation. female or male.

- HTTP 400 invalid_creatinine: creatinine_mg_dl (0.1-20) or creatinine_umol_l (9-1768) is required
- HTTP 400 invalid_age: age must be an integer from 18 to 120
- HTTP 400 invalid_sex: sex must be female or male
- HTTP 402 payment_required: Missing or invalid PAYMENT-SIGNATURE; decode the PAYMENT-REQUIRED header
- HTTP 409 payment_in_progress: The same authorization nonce is already being settled; retry shortly
- HTTP 429 rate_limited: Too many requests from this client
- HTTP 503 settlement_uncertain: Settlement is unconfirmed; retry with the same PAYMENT-SIGNATURE
- HTTP 503 facilitator_unavailable: Payment facilitator unavailable
- HTTP 503 facilitator_misconfigured: Payment facilitator is not configured
- HTTP 503 facilitator_unauthorized: Payment facilitator rejected credentials
- HTTP 503 ledger_unavailable: Payment ledger unavailable
- HTTP 503 payment_unavailable: Payment processing unavailable

Example 200 (fixture, not a live lookup):

{
  "units": "mL/min/1.73m2",
  "disclaimer": "Not a medical device. Deterministic published-formula or coded-ontology output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
  "age_years": 65,
  "citation": {
    "authors": "Inker LA, Eneanya ND, Coresh J, et al.",
    "doi": "10.1056/NEJMoa2102953",
    "id": "inker-2021",
    "source": "N Engl J Med. 2021;385(19):1737-1749",
    "title": "New Creatinine- and Cystatin C-Based Equations to Estimate GFR without Race"
  },
  "creatinine_mg_dl": 1.1,
  "egfr_ml_min_1_73m2": 55.8,
  "formula": "ckd_epi_2021_creatinine",
  "formula_expression": "142 * min(Scr/κ,1)^α * max(Scr/κ,1)^(-1.200) * 0.9938^age * (1.012 if female)",
  "sex": "female"
}

## CHA2DS2-VASc

GET /api/calc/cha2ds2_vasc
Price: $0.005 USDC (5000 atomic) on eip155:8453
Example: https://api.magentlab.com/api/calc/cha2ds2_vasc?age=78&sex=female&chf=false&hypertension=true&diabetes=true&stroke_tia=false&vascular_disease=false
Human docs: https://magentlab.com/docs/cha2ds2-vasc

x402 V2 curl (expect 402 until paid):

curl -i -H "Accept: application/json" "https://api.magentlab.com/api/calc/cha2ds2_vasc?age=78&sex=female&chf=false&hypertension=true&diabetes=true&stroke_tia=false&vascular_disease=false"

- age (query, required): Age in years (18-120). ≥75 scores 2; 65-74 scores 1.
- sex (query, required, enum female|male): female scores 1 (Sc); male scores 0.
- chf (query, required): Congestive heart failure or LV dysfunction. true or false.
- hypertension (query, required): Hypertension history. true or false.
- diabetes (query, required): Diabetes mellitus. true or false.
- stroke_tia (query, required): Prior stroke, TIA, or thromboembolism. true or false (2 points).
- vascular_disease (query, required): Prior MI, peripheral artery disease, or aortic plaque. true or false.

- HTTP 400 invalid_age: age must be an integer from 18 to 120
- HTTP 400 invalid_sex: sex must be female or male
- HTTP 400 invalid_flag: boolean clinical flags must be true or false
- HTTP 402 payment_required: Missing or invalid PAYMENT-SIGNATURE; decode the PAYMENT-REQUIRED header
- HTTP 409 payment_in_progress: The same authorization nonce is already being settled; retry shortly
- HTTP 429 rate_limited: Too many requests from this client
- HTTP 503 settlement_uncertain: Settlement is unconfirmed; retry with the same PAYMENT-SIGNATURE
- HTTP 503 facilitator_unavailable: Payment facilitator unavailable
- HTTP 503 facilitator_misconfigured: Payment facilitator is not configured
- HTTP 503 facilitator_unauthorized: Payment facilitator rejected credentials
- HTTP 503 ledger_unavailable: Payment ledger unavailable
- HTTP 503 payment_unavailable: Payment processing unavailable

Example 200 (fixture, not a live lookup):

{
  "components": [
    {
      "factor": "congestive_heart_failure",
      "points": 0,
      "present": false
    },
    {
      "factor": "hypertension",
      "points": 1,
      "present": true
    },
    {
      "value": 78,
      "factor": "age",
      "points": 2,
      "present": true
    },
    {
      "factor": "diabetes",
      "points": 1,
      "present": true
    },
    {
      "factor": "stroke_tia_thromboembolism",
      "points": 0,
      "present": false
    },
    {
      "factor": "vascular_disease",
      "points": 0,
      "present": false
    },
    {
      "factor": "sex_female",
      "points": 1,
      "present": true
    }
  ],
  "disclaimer": "Not a medical device. Deterministic published-formula or coded-ontology output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
  "age_years": 78,
  "citation": {
    "authors": "Lip GYH, Nieuwlaat R, Pisters R, Lane DA, Crijns HJ",
    "doi": "10.1378/chest.09-1584",
    "id": "lip-2010",
    "source": "Chest. 2010;137(2):263-272",
    "title": "Refining clinical risk stratification for predicting stroke and thromboembolism in atrial fibrillation using a novel risk factor-based approach: the euro heart survey on atrial fibrillation"
  },
  "formula": "cha2ds2_vasc",
  "sex": "female",
  "max_score": 9,
  "score": 5
}

## BMI

GET /api/calc/bmi
Price: $0.005 USDC (5000 atomic) on eip155:8453
Example: https://api.magentlab.com/api/calc/bmi?height_cm=170&weight_kg=70
Human docs: https://magentlab.com/docs/bmi

x402 V2 curl (expect 402 until paid):

curl -i -H "Accept: application/json" "https://api.magentlab.com/api/calc/bmi?height_cm=170&weight_kg=70"

- height_cm (query, optional): Height in centimeters. Provide height_cm or height_in.
- weight_kg (query, optional): Weight in kilograms. Provide weight_kg or weight_lb.
- height_in (query, optional): Height in inches. Converted as cm = in * 2.54.
- weight_lb (query, optional): Weight in pounds. Converted as kg = lb * 0.45359237.

- HTTP 400 invalid_height: height_cm (50-250) or height_in (20-98) is required
- HTTP 400 invalid_weight: weight_kg (1-500) or weight_lb (2-1100) is required
- HTTP 402 payment_required: Missing or invalid PAYMENT-SIGNATURE; decode the PAYMENT-REQUIRED header
- HTTP 409 payment_in_progress: The same authorization nonce is already being settled; retry shortly
- HTTP 429 rate_limited: Too many requests from this client
- HTTP 503 settlement_uncertain: Settlement is unconfirmed; retry with the same PAYMENT-SIGNATURE
- HTTP 503 facilitator_unavailable: Payment facilitator unavailable
- HTTP 503 facilitator_misconfigured: Payment facilitator is not configured
- HTTP 503 facilitator_unauthorized: Payment facilitator rejected credentials
- HTTP 503 ledger_unavailable: Payment ledger unavailable
- HTTP 503 payment_unavailable: Payment processing unavailable

Example 200 (fixture, not a live lookup):

{
  "disclaimer": "Not a medical device. Deterministic published-formula or coded-ontology output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
  "citation": {
    "authors": "Keys A, Fidanza F, Karvonen MJ, Kimura N, Taylor HL",
    "doi": "10.1016/0021-9681(72)90027-6",
    "id": "keys-1972",
    "source": "J Chronic Dis. 1972;25(6):329-343",
    "title": "Indices of relative weight and obesity"
  },
  "formula": "bmi",
  "formula_expression": "BMI = weight_kg / (height_m ^ 2)",
  "weight_kg": 70.0,
  "height_cm": 170.0,
  "bmi": 24.2,
  "who_adult_category": "normal"
}

## HAS-BLED

GET /api/calc/has_bled
Price: $0.005 USDC (5000 atomic) on eip155:8453
Example: https://api.magentlab.com/api/calc/has_bled?age=78&hypertension=true&abnormal_renal=false&abnormal_liver=false&stroke=false&bleeding=false&labile_inr=false&drugs=false&alcohol=false
Human docs: https://magentlab.com/docs/has-bled

x402 V2 curl (expect 402 until paid):

curl -i -H "Accept: application/json" "https://api.magentlab.com/api/calc/has_bled?age=78&hypertension=true&abnormal_renal=false&abnormal_liver=false&stroke=false&bleeding=false&labile_inr=false&drugs=false&alcohol=false"

- age (query, required): Age in years (18-120). Age >65 scores 1 (E).
- hypertension (query, required): Uncontrolled hypertension (H). true or false.
- abnormal_renal (query, required): Abnormal renal function (A). true or false.
- abnormal_liver (query, required): Abnormal liver function (A). true or false. Renal and liver each score 1.
- stroke (query, required): Prior stroke (S). true or false.
- bleeding (query, required): Bleeding history or predisposition (B). true or false.
- labile_inr (query, required): Labile INR (L). true or false.
- drugs (query, required): Concomitant antiplatelet or NSAID (D). true or false.
- alcohol (query, required): Alcohol excess (D). true or false. Drugs and alcohol each score 1.

- HTTP 400 invalid_age: age must be an integer from 18 to 120
- HTTP 400 invalid_flag: boolean clinical flags must be true or false
- HTTP 402 payment_required: Missing or invalid PAYMENT-SIGNATURE; decode the PAYMENT-REQUIRED header
- HTTP 409 payment_in_progress: The same authorization nonce is already being settled; retry shortly
- HTTP 429 rate_limited: Too many requests from this client
- HTTP 503 settlement_uncertain: Settlement is unconfirmed; retry with the same PAYMENT-SIGNATURE
- HTTP 503 facilitator_unavailable: Payment facilitator unavailable
- HTTP 503 facilitator_misconfigured: Payment facilitator is not configured
- HTTP 503 facilitator_unauthorized: Payment facilitator rejected credentials
- HTTP 503 ledger_unavailable: Payment ledger unavailable
- HTTP 503 payment_unavailable: Payment processing unavailable

Example 200 (fixture, not a live lookup):

{
  "components": [
    {
      "factor": "hypertension",
      "points": 1,
      "present": true
    },
    {
      "factor": "abnormal_renal",
      "points": 0,
      "present": false
    },
    {
      "factor": "abnormal_liver",
      "points": 0,
      "present": false
    },
    {
      "factor": "stroke",
      "points": 0,
      "present": false
    },
    {
      "factor": "bleeding",
      "points": 0,
      "present": false
    },
    {
      "factor": "labile_inr",
      "points": 0,
      "present": false
    },
    {
      "value": 78,
      "factor": "elderly_age_gt_65",
      "points": 1,
      "present": true
    },
    {
      "factor": "drugs",
      "points": 0,
      "present": false
    },
    {
      "factor": "alcohol",
      "points": 0,
      "present": false
    }
  ],
  "disclaimer": "Not a medical device. Deterministic published-formula or coded-ontology output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
  "age_years": 78,
  "citation": {
    "authors": "Pisters R, Lane DA, Nieuwlaat R, de Vos CB, Crijns HJ, Lip GYH",
    "doi": "10.1378/chest.10-0134",
    "id": "pisters-2010",
    "source": "Chest. 2010;138(5):1093-1100",
    "title": "A novel user-friendly score (HAS-BLED) to assess 1-year risk of major bleeding in patients with atrial fibrillation: the Euro Heart Survey"
  },
  "formula": "has_bled",
  "max_score": 9,
  "score": 2
}

## Cockcroft–Gault CrCl

GET /api/calc/crcl_cockcroft_gault
Price: $0.005 USDC (5000 atomic) on eip155:8453
Example: https://api.magentlab.com/api/calc/crcl_cockcroft_gault?age=65&sex=female&weight_kg=70&creatinine_mg_dl=1.1
Human docs: https://magentlab.com/docs/crcl

x402 V2 curl (expect 402 until paid):

curl -i -H "Accept: application/json" "https://api.magentlab.com/api/calc/crcl_cockcroft_gault?age=65&sex=female&weight_kg=70&creatinine_mg_dl=1.1"

- age (query, required): Age in years (18-120).
- sex (query, required, enum female|male): female applies the published 0.85 factor; male does not.
- weight_kg (query, optional): Total body weight in kilograms. Provide weight_kg or weight_lb.
- weight_lb (query, optional): Total body weight in pounds. Converted as kg = lb * 0.45359237.
- creatinine_mg_dl (query, optional): Serum creatinine in mg/dL. Provide this or creatinine_umol_l.
- creatinine_umol_l (query, optional): Serum creatinine in µmol/L. Converted as mg/dL = µmol/L / 88.42.

- HTTP 400 invalid_age: age must be an integer from 18 to 120
- HTTP 400 invalid_sex: sex must be female or male
- HTTP 400 invalid_weight: weight_kg (1-500) or weight_lb (2-1100) is required
- HTTP 400 invalid_creatinine: creatinine_mg_dl (0.1-20) or creatinine_umol_l (9-1768) is required
- HTTP 402 payment_required: Missing or invalid PAYMENT-SIGNATURE; decode the PAYMENT-REQUIRED header
- HTTP 409 payment_in_progress: The same authorization nonce is already being settled; retry shortly
- HTTP 429 rate_limited: Too many requests from this client
- HTTP 503 settlement_uncertain: Settlement is unconfirmed; retry with the same PAYMENT-SIGNATURE
- HTTP 503 facilitator_unavailable: Payment facilitator unavailable
- HTTP 503 facilitator_misconfigured: Payment facilitator is not configured
- HTTP 503 facilitator_unauthorized: Payment facilitator rejected credentials
- HTTP 503 ledger_unavailable: Payment ledger unavailable
- HTTP 503 payment_unavailable: Payment processing unavailable

Example 200 (fixture, not a live lookup):

{
  "units": "mL/min",
  "disclaimer": "Not a medical device. Deterministic published-formula or coded-ontology output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
  "age_years": 65,
  "citation": {
    "authors": "Cockcroft DW, Gault MH",
    "doi": "10.1159/000180580",
    "id": "cockcroft-1976",
    "source": "Nephron. 1976;16(1):31-41",
    "title": "Prediction of creatinine clearance from serum creatinine"
  },
  "creatinine_mg_dl": 1.1,
  "formula": "cockcroft_gault",
  "formula_expression": "CrCl_mL_min = ((140 - age) * weight_kg * (0.85 if female else 1)) / (72 * Scr_mg_dL)",
  "sex": "female",
  "weight_kg": 70.0,
  "crcl_ml_min": 56.3,
  "weight_basis": "total_body_weight"
}

## FIB-4

GET /api/calc/fib4
Price: $0.005 USDC (5000 atomic) on eip155:8453
Example: https://api.magentlab.com/api/calc/fib4?age=50&ast_u_l=100&alt_u_l=40&platelets_10e9_l=200
Human docs: https://magentlab.com/docs/fib4

x402 V2 curl (expect 402 until paid):

curl -i -H "Accept: application/json" "https://api.magentlab.com/api/calc/fib4?age=50&ast_u_l=100&alt_u_l=40&platelets_10e9_l=200"

- age (query, required): Age in years (18-120).
- ast_u_l (query, required): Aspartate aminotransferase in U/L (1-10000).
- alt_u_l (query, required): Alanine aminotransferase in U/L (1-10000).
- platelets_10e9_l (query, required): Platelet count in 10^9/L (1-2000).

- HTTP 400 invalid_age: age must be an integer from 18 to 120
- HTTP 400 invalid_ast: ast_u_l must be a number from 1 to 10000
- HTTP 400 invalid_alt: alt_u_l must be a number from 1 to 10000
- HTTP 400 invalid_platelets: platelets_10e9_l must be a number from 1 to 2000
- HTTP 402 payment_required: Missing or invalid PAYMENT-SIGNATURE; decode the PAYMENT-REQUIRED header
- HTTP 409 payment_in_progress: The same authorization nonce is already being settled; retry shortly
- HTTP 429 rate_limited: Too many requests from this client
- HTTP 503 settlement_uncertain: Settlement is unconfirmed; retry with the same PAYMENT-SIGNATURE
- HTTP 503 facilitator_unavailable: Payment facilitator unavailable
- HTTP 503 facilitator_misconfigured: Payment facilitator is not configured
- HTTP 503 facilitator_unauthorized: Payment facilitator rejected credentials
- HTTP 503 ledger_unavailable: Payment ledger unavailable
- HTTP 503 payment_unavailable: Payment processing unavailable

Example 200 (fixture, not a live lookup):

{
  "disclaimer": "Not a medical device. Deterministic published-formula or coded-ontology output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
  "age_years": 50,
  "citation": {
    "authors": "Sterling RK, Lissen E, Clumeck N, et al.",
    "doi": "10.1002/hep.21172",
    "id": "sterling-2006",
    "source": "Hepatology. 2006;43(6):1317-1325",
    "title": "Development of a simple noninvasive index to predict significant fibrosis in patients with HIV/HCV coinfection"
  },
  "formula": "fib4",
  "formula_expression": "FIB-4 = (age_years * AST_U_L) / (platelets_10e9_L * sqrt(ALT_U_L))",
  "alt_u_l": 40.0,
  "ast_u_l": 100.0,
  "fib4": 3.95,
  "platelets_10e9_l": 200.0,
  "sterling_band": "high"
}

## Payment smoke (not a product)

GET /v1/tools/ping — $0.001 USDC. Confirms the x402 gate and PAYMENT-RESPONSE. Not a product tool. Do not call for production work. Not listed on Bazaar.
Do not call GET /v1/tools/ping for production work; it is a payment smoke test only.

## Not a medical device

Outputs are deterministic codes and published-formula arithmetic. A licensed clinician remains responsible for care.