magent
Ottawa Heart Failure Risk Scale (OHFRS; Stiell 2013 derivation). Ten caller-assigned flags (stroke/TIA 1, intubation 2, arrival HR >=110 2, arrival SaO2 <90% 1, walk-test HR >=110 or unable 1, new ischemic ECG 2, urea >=12 mmol/L 1, CO2 >=35 mmol/L 2, troponin at MI level 2, NT-proBNP >=5000 ng/L 1); integer points, max 15. Derivation SAE risk 2.8% to 89.0%. Not a medical device, not a disposition or discharge order, not EHMRG. magent does not walk the patient or read the ECG.
TradingLiveeip155:8453Exactvia cdp
OhfrsHeart-failureEmergencyStiellCalculator
Calls · 30d
3→ 0%
This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 15 snapshots so far.
$13.75
Verified settled volume
2,750 settlements proven x402 by their on-chain EIP-3009 marker.
$0.0050
Listed price
As published in the catalog. Always read the live 402 before paying.
3
Calls · 30d
Upstream's own call count for this endpoint, not ours.
1
Unique payers · 30d
Last called 2026-08-31 13:28Z
—
Upstream on-chain volume
Reported by the source catalog.
Paid to
0x836Be278f1739fB4308091cD1852F7971Bc19Ee2The wallet the 402 directs payment to. Its whole payment record — every payer, every chain — is on the merchant page.
Asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913
Provider
The payTo wallet does not resolve to a registered ERC-8004 agent. That is not a verdict on the service — most of the catalog is unregistered.
Live 402 challenge
Captured by the enrichment pass, not read just now. Prices can change — always read the 402 the endpoint answers with.
{
"error": "PAYMENT-SIGNATURE header is required",
"accepts": [
{
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"extra": {
"name": "USD Coin",
"version": "2",
"paymentFlow": "upfront",
"resourceUrl": "https://api.magentlab.com/api/calc/ohfrs",
"assetTransferMethod": "eip3009"
},
"payTo": "0x836Be278f1739fB4308091cD1852F7971Bc19Ee2",
"amount": "5000",
"scheme": "exact",
"network": "eip155:8453",
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},
{
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"extra": {
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"withdrawDelay": 86400,
"receiverAuthorizer": "0x3721824a31197dcDD2984cF43b92B6cc8A87c0Fb",
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"payTo": "0x836Be278f1739fB4308091cD1852F7971Bc19Ee2",
"amount": "5000",
"scheme": "batch-settlement",
"network": "eip155:8453",
"maxTimeoutSeconds": 600
}
],
"resource": {
"url": "https://api.magentlab.com/api/calc/ohfrs",
"tags": [
"ohfrs",
"heart-failure",
"emergency",
"stiell",
"calculator"
],
"mimeType": "application/json",
"description": "Ottawa Heart Failure Risk Scale (OHFRS; Stiell 2013 derivation). Ten caller-assigned flags (stroke/TIA 1, intubation 2, arrival HR >=110 2, arrival SaO2 <90% 1, walk-test HR >=110 or unable 1, new ischemic ECG 2, urea >=12 mmol/L 1, CO2 >=35 mmol/L 2, troponin at MI level 2, NT-proBNP >=5000 ng/L 1); integer points, max 15. Derivation SAE risk 2.8% to 89.0%. Not a medical device, not a disposition or discharge order, not EHMRG. magent does not walk the patient or read the ECG.",
"serviceName": "magent"
},
"extensions": {
"bazaar": {
"info": {
"input": {
"type": "http",
"method": "GET",
"queryParams": {
"co2_ge_35_mmol_l": false,
"new_ischemic_ecg": false,
"ntprobnp_ge_5000": false,
"hr_arrival_ge_110": false,
"troponin_mi_level": false,
"urea_ge_12_mmol_l": false,
"sao2_lt_90_arrival": false,
"history_stroke_or_tia": false,
"walk_test_hr_ge_110_or_unable": false,
"intubation_respiratory_distress": false
}
},
"output": {
"type": "json",
"example": {
"score": 0,
"formula": "ohfrs",
"citation": {
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"doi": "10.1111/acem.12056",
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"authors": "Stiell IG, Clement CM, Brison RJ, et al."
},
"max_score": 15,
"components": [
{
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{
"factor": "intubation_respiratory_distress",
"points": 0,
"present": false
},
{
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"points": 0,
"present": false
},
{
"factor": "sao2_lt_90_arrival",
"points": 0,
"present": false
},
{
"factor": "walk_test_hr_ge_110_or_unable",
"points": 0,
"present": false
},
{
"factor": "new_ischemic_ecg",
"points": 0,
"present": false
},
{
"factor": "urea_ge_12_mmol_l",
"points": 0,
"present": false
},
{
"factor": "co2_ge_35_mmol_l",
"points": 0,
"present": false
},
{
"factor": "troponin_mi_level",
"points": 0,
"present": false
},
{
"factor": "ntprobnp_ge_5000",
"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.",
"formula_expression": "OHFRS = history_stroke_or_tia(1) + intubation_respiratory_distress(2) + hr_arrival_ge_110(2) + sao2_lt_90_arrival(1) + walk_test_hr_ge_110_or_unable(1) + new_ischemic_ecg(2) + urea_ge_12_mmol_l(1) + co2_ge_35_mmol_l(2) + troponin_mi_level(2) + ntprobnp_ge_5000(1); Stiell 2013 derivation; max 15; SAE risk varied from 2.8% to 89.0%; admission thresholds of total score 1, 2, or 3 had sensitivities 95.2 / 80.6 / 64.5%"
}
},
"iconUrl": "https://api.magentlab.com/favicon.ico"
},
"schema": {
"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": [
"history_stroke_or_tia",
"intubation_respiratory_distress",
"hr_arrival_ge_110",
"sao2_lt_90_arrival",
"walk_test_hr_ge_110_or_unable",
"new_ischemic_ecg",
"urea_ge_12_mmol_l",
"co2_ge_35_mmol_l",
"troponin_mi_level",
"ntprobnp_ge_5000"
],
"properties": {
"co2_ge_35_mmol_l": {
"type": "boolean",
"description": "Serum CO2 >=35 mmol/L as assigned by the caller after applying the Stiell 2013 cutoff (2 points if true). true or false. magent does not assay CO2."
},
"new_ischemic_ecg": {
"type": "boolean",
"description": "New ischemic ECG changes as assigned by the caller (Stiell 2013 derivation; 2 points if true). true or false. magent does not interpret the ECG."
},
"ntprobnp_ge_5000": {
"type": "boolean",
"description": "NT-proBNP >=5000 ng/L as assigned by the caller after applying the Stiell 2013 cutoff (1 point if true). true or false. magent does not assay NT-proBNP."
},
"hr_arrival_ge_110": {
"type": "boolean",
"description": "Heart rate on ED arrival >=110 as assigned by the caller after applying the Stiell 2013 cutoff (2 points if true). true or false. magent does not measure heart rate."
},
"troponin_mi_level": {
"type": "boolean",
"description": "Troponin I or T elevated to MI level as assigned by the caller (Stiell 2013; 2 points if true). true or false. magent does not assay troponin."
},
"urea_ge_12_mmol_l": {
"type": "boolean",
"description": "Urea >=12 mmol/L as assigned by the caller after applying the Stiell 2013 cutoff (1 point if true). true or false. magent does not assay urea."
},
"sao2_lt_90_arrival": {
"type": "boolean",
"description": "Oxygen saturation <90% on ED arrival as assigned by the caller after applying the Stiell 2013 cutoff (1 point if true). true or false. magent does not measure saturation."
},
"history_stroke_or_tia": {
"type": "boolean",
"description": "History of stroke or TIA as assigned by the caller (Stiell 2013; 1 point if true). true or false. magent does not take the history."
},
"walk_test_hr_ge_110_or_unable": {
"type": "boolean",
"description": "Heart rate >=110 during the 3-minute walk test, or unable to perform the walk test, as assigned by the caller after ED intervention (Stiell 2013; 1 point if true). true or false. magent does not walk the patient."
},
"intubation_respiratory_distress": {
"type": "boolean",
"description": "Intubation for respiratory distress as assigned by the caller (Stiell 2013; 2 points if true). true or false."
}
}
}
},
"additionalProperties": false
},
"output": {
"type": "object",
"required": [
"type"
],
"properties": {
"type": {
"type": "string"
},
"example": {
"type": "object"
}
}
}
}
}
}
},
"x402Version": 2
}Accepts
The payment requirements as published to the catalog. Read the live 402 before paying — a price here is a claim, not a quote.
0.005USDC≈ $0.005 USD
on Base · exact scheme
Pay 0.005 USDC on Base to 0x836B…19Ee2. The signed payment is good for 10 minutes.
- Paid to
- 0x836B…19Ee2
- USD Coin contract
- 0x8335…02913
- Payment window
- 10 minutes
- As published
- 5000 smallest units
The catalog’s raw entry
[
{
"asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
"extra": {
"name": "USD Coin",
"version": "2",
"paymentFlow": "upfront",
"resourceUrl": "https://api.magentlab.com/api/calc/ohfrs",
"assetTransferMethod": "eip3009"
},
"payTo": "0x836Be278f1739fB4308091cD1852F7971Bc19Ee2",
"amount": "5000",
"scheme": "exact",
"network": "eip155:8453",
"maxTimeoutSeconds": 600
}
]Extensions
{
"bazaar": {
"info": {
"input": {
"body": {
"items": [
{
"co2_ge_35_mmol_l": false,
"new_ischemic_ecg": false,
"ntprobnp_ge_5000": false,
"hr_arrival_ge_110": false,
"troponin_mi_level": false,
"urea_ge_12_mmol_l": false,
"sao2_lt_90_arrival": false,
"history_stroke_or_tia": false,
"walk_test_hr_ge_110_or_unable": false,
"intubation_respiratory_distress": false
},
{
"co2_ge_35_mmol_l": false,
"new_ischemic_ecg": false,
"ntprobnp_ge_5000": false,
"hr_arrival_ge_110": false,
"troponin_mi_level": false,
"urea_ge_12_mmol_l": false,
"sao2_lt_90_arrival": false,
"history_stroke_or_tia": false,
"walk_test_hr_ge_110_or_unable": false,
"intubation_respiratory_distress": false
}
]
},
"type": "http",
"method": "POST"
},
"output": {
"type": "json",
"example": {
"path": "/api/calc/ohfrs",
"count": 2,
"items": [
{
"score": 0,
"formula": "ohfrs",
"citation": {
"id": "stiell-2013",
"doi": "10.1111/acem.12056",
"pmid": "23570474",
"title": "A risk scoring system to identify emergency department patients with heart failure at high risk for serious adverse events",
"source": "Acad Emerg Med. 2013;20(1):17-26",
"authors": "Stiell IG, Clement CM, Brison RJ, et al."
},
"max_score": 15,
"components": [
{
"factor": "history_stroke_or_tia",
"points": 0,
"present": false
},
{
"factor": "intubation_respiratory_distress",
"points": 0,
"present": false
},
{
"factor": "hr_arrival_ge_110",
"points": 0,
"present": false
},
{
"factor": "sao2_lt_90_arrival",
"points": 0,
"present": false
},
{
"factor": "walk_test_hr_ge_110_or_unable",
"points": 0,
"present": false
},
{
"factor": "new_ischemic_ecg",
"points": 0,
"present": false
},
{
"factor": "urea_ge_12_mmol_l",
"points": 0,
"present": false
},
{
"factor": "co2_ge_35_mmol_l",
"points": 0,
"present": false
},
{
"factor": "troponin_mi_level",
"points": 0,
"present": false
},
{
"factor": "ntprobnp_ge_5000",
"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.",
"formula_expression": "OHFRS = history_stroke_or_tia(1) + intubation_respiratory_distress(2) + hr_arrival_ge_110(2) + sao2_lt_90_arrival(1) + walk_test_hr_ge_110_or_unable(1) + new_ischemic_ecg(2) + urea_ge_12_mmol_l(1) + co2_ge_35_mmol_l(2) + troponin_mi_level(2) + ntprobnp_ge_5000(1); Stiell 2013 derivation; max 15; SAE risk varied from 2.8% to 89.0%; admission thresholds of total score 1, 2, or 3 had sensitivities 95.2 / 80.6 / 64.5%"
},
{
"score": 0,
"formula": "ohfrs",
"citation": {
"id": "stiell-2013",
"doi": "10.1111/acem.12056",
"pmid": "23570474",
"title": "A risk scoring system to identify emergency department patients with heart failure at high risk for serious adverse events",
"source": "Acad Emerg Med. 2013;20(1):17-26",
"authors": "Stiell IG, Clement CM, Brison RJ, et al."
},
"max_score": 15,
"components": [
{
"factor": "history_stroke_or_tia",
"points": 0,
"present": false
},
{
"factor": "intubation_respiratory_distress",
"points": 0,
"present": false
},
{
"factor": "hr_arrival_ge_110",
"points": 0,
"present": false
},
{
"factor": "sao2_lt_90_arrival",
"points": 0,
"present": false
},
{
"factor": "walk_test_hr_ge_110_or_unable",
"points": 0,
"present": false
},
{
"factor": "new_ischemic_ecg",
"points": 0,
"present": false
},
{
"factor": "urea_ge_12_mmol_l",
"points": 0,
"present": false
},
{
"factor": "co2_ge_35_mmol_l",
"points": 0,
"present": false
},
{
"factor": "troponin_mi_level",
"points": 0,
"present": false
},
{
"factor": "ntprobnp_ge_5000",
"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.",
"formula_expression": "OHFRS = history_stroke_or_tia(1) + intubation_respiratory_distress(2) + hr_arrival_ge_110(2) + sao2_lt_90_arrival(1) + walk_test_hr_ge_110_or_unable(1) + new_ischemic_ecg(2) + urea_ge_12_mmol_l(1) + co2_ge_35_mmol_l(2) + troponin_mi_level(2) + ntprobnp_ge_5000(1); Stiell 2013 derivation; max 15; SAE risk varied from 2.8% to 89.0%; admission thresholds of total score 1, 2, or 3 had sensitivities 95.2 / 80.6 / 64.5%"
}
]
}
},
"iconUrl": "https://api.magentlab.com/favicon.ico"
},
"schema": {
"type": "object",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"required": [
"input"
],
"properties": {
"input": {
"type": "object",
"required": [
"type",
"method"
],
"properties": {
"body": {
"type": "object",
"required": [
"items"
],
"properties": {
"items": {
"type": "array",
"items": {
"type": "object",
"required": [
"history_stroke_or_tia",
"intubation_respiratory_distress",
"hr_arrival_ge_110",
"sao2_lt_90_arrival",
"walk_test_hr_ge_110_or_unable",
"new_ischemic_ecg",
"urea_ge_12_mmol_l",
"co2_ge_35_mmol_l",
"troponin_mi_level",
"ntprobnp_ge_5000"
],
"properties": {
"co2_ge_35_mmol_l": {
"type": "boolean",
"description": "Serum CO2 >=35 mmol/L as assigned by the caller after applying the Stiell 2013 cutoff (2 points if true). true or false. magent does not assay CO2."
},
"new_ischemic_ecg": {
"type": "boolean",
"description": "New ischemic ECG changes as assigned by the caller (Stiell 2013 derivation; 2 points if true). true or false. magent does not interpret the ECG."
},
"ntprobnp_ge_5000": {
"type": "boolean",
"description": "NT-proBNP >=5000 ng/L as assigned by the caller after applying the Stiell 2013 cutoff (1 point if true). true or false. magent does not assay NT-proBNP."
},
"hr_arrival_ge_110": {
"type": "boolean",
"description": "Heart rate on ED arrival >=110 as assigned by the caller after applying the Stiell 2013 cutoff (2 points if true). true or false. magent does not measure heart rate."
},
"troponin_mi_level": {
"type": "boolean",
"description": "Troponin I or T elevated to MI level as assigned by the caller (Stiell 2013; 2 points if true). true or false. magent does not assay troponin."
},
"urea_ge_12_mmol_l": {
"type": "boolean",
"description": "Urea >=12 mmol/L as assigned by the caller after applying the Stiell 2013 cutoff (1 point if true). true or false. magent does not assay urea."
},
"sao2_lt_90_arrival": {
"type": "boolean",
"description": "Oxygen saturation <90% on ED arrival as assigned by the caller after applying the Stiell 2013 cutoff (1 point if true). true or false. magent does not measure saturation."
},
"history_stroke_or_tia": {
"type": "boolean",
"description": "History of stroke or TIA as assigned by the caller (Stiell 2013; 1 point if true). true or false. magent does not take the history."
},
"walk_test_hr_ge_110_or_unable": {
"type": "boolean",
"description": "Heart rate >=110 during the 3-minute walk test, or unable to perform the walk test, as assigned by the caller after ED intervention (Stiell 2013; 1 point if true). true or false. magent does not walk the patient."
},
"intubation_respiratory_distress": {
"type": "boolean",
"description": "Intubation for respiratory distress as assigned by the caller (Stiell 2013; 2 points if true). true or false."
}
}
},
"maxItems": 25,
"minItems": 1
}
},
"additionalProperties": false
},
"type": {
"type": "string",
"const": "http"
},
"method": {
"type": "string",
"const": "POST"
},
"headers": {
"type": "object",
"additionalProperties": {
"type": "string"
}
}
},
"additionalProperties": false
},
"output": {
"type": "object",
"required": [
"type"
],
"properties": {
"type": {
"type": "string"
},
"example": {
"type": "object"
}
}
}
}
}
}
}Provenance
- Seen in the source catalog
- 2026-08-31 13:28Z
- Last indexed by Roundhouse
- 2026-09-07 06:20Z
- Last enriched (probe, favicon, geo)
- 2026-09-24 04:15Z
- x402 version
- 2
- Max timeout
- 600s
- Liveness probe
- HTTP 402
Hand this page to an agent
Copy the prompt and paste it into Claude, an MCP client or your own agent — it will vet this service and call it over the free read API. No key, no account.
GET api.roundhouseai.io/v0/endpoints
This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 15 snapshots so far. Verified volume counts only settlements with an on-chain EIP-3009 marker.
Show the promptHide the prompt
Using Roundhouse, look up the x402 service magent and tell me whether it is worth paying: what a call costs, whether the endpoint answered when last probed, and what its payment record actually shows. curl -s 'https://api.roundhouseai.io/v0/endpoints?q=magent' curl -s 'https://api.roundhouseai.io/v0/merchants/<the payTo wallet returned above>' Then call it: read the price from the live 402 at https://api.magentlab.com/api/calc/ohfrs, never from a cached figure, and pay with an x402 client. The /v0 API needs an API key (`authorization: Bearer rh_live_…`) on everything except /v0/unified* and /v0/endpoints. Mint a personal key for $0.01 at GET https://api.roundhouseai.io/v0/test/x402, or use an organization key from https://roundhouseai.io/dashboard/team. If you do not have Roundhouse tools or skills installed, read https://roundhouseai.io/skill.md first — it is the whole procedure.