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CHA2DS2-VASc

Deterministic stroke-risk score from discrete flags. Chest 2010 citation.

LIVE $0.005 USDC GET /api/calc/cha2ds2_vasc

When to use

CHA2DS2-VASc score from discrete clinical flags. Use for stroke-risk stratification arithmetic in atrial fibrillation. Deterministic published score with citation.

Try

Opens the live endpoint. Unpaid browser requests show the paywall; agents should send Accept: application/json.

/api/calc/cha2ds2_vasc?age=78&sex=female&chf=false&hypertension=true&diabetes=true&stroke_tia=false&vascular_disease=false

Full URL: https://api.magentlab.com/api/calc/cha2ds2_vasc?age=78&sex=female&chf=false&hypertension=true&diabetes=true&stroke_tia=false&vascular_disease=false

Request

GET /api/calc/cha2ds2_vasc · x402 V2 · USDC on Base · $0.005 USDC

x402 V2 curl

Expect HTTP 402 and a PAYMENT-REQUIRED header until you retry with PAYMENT-SIGNATURE. 

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"

Cursor mcp.json

Intended config for @magent/mcp. This is not npm @x402/fetch (a payment fetch wrapper). 

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

Query parameters

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

Success fields

Field Type Description
formula string cha2ds2_vasc
score integer Total points 0-9
max_score integer Always 9
sex string female or male
age_years integer Age used for A2/A scoring
components array Per-factor points
citation object Chest 2010 citation
disclaimer string Not-a-device notice

Example

Frozen 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
}

Payment

Unpaid requests return HTTP 402 with a base64 PAYMENT-REQUIRED header. Retry the same URL with PAYMENT-SIGNATURE. Settlement completes before the tool runs. Full handshake and shared payment errors: Payments.

Errors

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

Guarantees

  • Settlement finishes before the tool executes. Uncertain settlement fails closed (HTTP 503).
  • Lookups run on our nodes — no third-party data API wrappers.
  • Localhost, IP literals, and metadata hostnames are rejected.
  • Execution is timeout-bounded and concurrency-capped.