GI · WEDGE

Prague C and M criteria for Barrett esophagus

Prague C & M

Format Sharma 2006 Prague C and M criteria as C{c}M{m} from caller-assigned circumferential (c_cm) and maximal (m_cm) extent of visualized Barrett mucosa in centimetres above the gastroesophageal junction.

WEDGE $0.005 USDC GET /api/calc/prague

Markdown: /docs/prague.md · Canonical: https://magentlab.com/docs/prague

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

What it computes

Format Sharma 2006 Prague C and M criteria as C{c}M{m} from caller-assigned circumferential (c_cm) and maximal (m_cm) extent of visualized Barrett mucosa in centimetres above the gastroesophageal junction.

When to use

When an agent already has endoscopic C and M measurements in centimetres and needs the published Prague label. magent does not perform endoscopy or diagnose Barrett esophagus.

When not to use

• Not a medical device.
• Not a Barrett esophagus diagnosis. Histology is required. magent does not perform endoscopy.
• The caller assigns c_cm and m_cm. magent does not measure lesions or interpret endoscopy images.
• This tool is Sharma 2006 Prague C and M extent only. Not Los Angeles oesophagitis grading (LA A-D). Not a histology diagnosis.
• C=0 is allowed (no circumferential Barrett; tongues only). M must be greater than or equal to C. Inputs are integers 0-20 cm.

Formula

prague is C{c_cm}M{m_cm} (no spaces) from caller-assigned circumferential extent c_cm (cm of visualized Barrett above the gastroesophageal junction, integer 0-20) and maximal extent m_cm (cm above GEJ, integer 0-20); m_cm must be >= c_cm; C=0 is no circumferential Barrett (tongues only); Sharma 2006 Prague C and M; not a Barrett diagnosis (histology required); magent does not perform endoscopy

Citation

Title

The development and validation of an endoscopic grading system for Barrett's esophagus: the Prague C & M criteria.

Authors

Sharma P, Dent J, Armstrong D, et al.

Source

Gastroenterology. 2006;131(5):1392-1399

DOI

10.1053/j.gastro.2006.08.032

Worked example

Also searched as

• Prague C and M
• Prague criteria Barrett
• Barrett C and M
• Sharma 2006 Prague
• circumferential Barrett extent
• maximal Barrett extent
• Prague C&M criteria
• Barrett esophagus Prague
• C and M criteria
• gastroesophageal junction Barrett

Try

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

/api/calc/prague?c_cm=0&m_cm=0

Full URL: https://api.magentlab.com/api/calc/prague?c_cm=0&m_cm=0

Call

Expect HTTP 402 until you retry with PAYMENT-SIGNATURE. Incomplete query params return HTTP 400 before any quote or charge.

curl -i -H "Accept: application/json" "https://api.magentlab.com/api/calc/prague?c_cm=0&m_cm=0"

Parameters

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.

POST /api/calc/prague Max 25 unit_amount + extra_item_amount * (n - 1) extra $0.002 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 (fixture)

{
  "items": [
    {
      "c_cm": "0",
      "m_cm": "0"
    },
    {
      "c_cm": "0",
      "m_cm": "0"
    }
  ]
}

Open bulk paywall →

Opens a two-item fixture on the API host. Unpaid browsers get the same MetaMask paywall as GET; Pay retries POST with those items.

Example 200 (fixture)

{
  "count": 2,
  "path": "/api/calc/prague",
  "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": "Sharma P, Dent J, Armstrong D, et al.",
        "doi": "10.1053/j.gastro.2006.08.032",
        "id": "sharma-2006",
        "pmid": "17101315",
        "source": "Gastroenterology. 2006;131(5):1392-1399",
        "title": "The development and validation of an endoscopic grading system for Barrett's esophagus: the Prague C & M criteria."
      },
      "formula": "prague",
      "formula_expression": "prague is C{c_cm}M{m_cm} (no spaces) from caller-assigned circumferential extent c_cm (cm of visualized Barrett above the gastroesophageal junction, integer 0-20) and maximal extent m_cm (cm above GEJ, integer 0-20); m_cm must be >= c_cm; C=0 is no circumferential Barrett (tongues only); Sharma 2006 Prague C and M; not a Barrett diagnosis (histology required); magent does not perform endoscopy",
      "c_cm": 0,
      "m_cm": 0,
      "prague": "C0M0"
    },
    {
      "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": "Sharma P, Dent J, Armstrong D, et al.",
        "doi": "10.1053/j.gastro.2006.08.032",
        "id": "sharma-2006",
        "pmid": "17101315",
        "source": "Gastroenterology. 2006;131(5):1392-1399",
        "title": "The development and validation of an endoscopic grading system for Barrett's esophagus: the Prague C & M criteria."
      },
      "formula": "prague",
      "formula_expression": "prague is C{c_cm}M{m_cm} (no spaces) from caller-assigned circumferential extent c_cm (cm of visualized Barrett above the gastroesophageal junction, integer 0-20) and maximal extent m_cm (cm above GEJ, integer 0-20); m_cm must be >= c_cm; C=0 is no circumferential Barrett (tongues only); Sharma 2006 Prague C and M; not a Barrett diagnosis (histology required); magent does not perform endoscopy",
      "c_cm": 0,
      "m_cm": 0,
      "prague": "C0M0"
    }
  ]
}

Response

Example JSON

Machine form of the same example. Frozen fixture. Not a live lookup.

{
  "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": "Sharma P, Dent J, Armstrong D, et al.",
    "doi": "10.1053/j.gastro.2006.08.032",
    "id": "sharma-2006",
    "pmid": "17101315",
    "source": "Gastroenterology. 2006;131(5):1392-1399",
    "title": "The development and validation of an endoscopic grading system for Barrett's esophagus: the Prague C & M criteria."
  },
  "formula": "prague",
  "formula_expression": "prague is C{c_cm}M{m_cm} (no spaces) from caller-assigned circumferential extent c_cm (cm of visualized Barrett above the gastroesophageal junction, integer 0-20) and maximal extent m_cm (cm above GEJ, integer 0-20); m_cm must be >= c_cm; C=0 is no circumferential Barrett (tongues only); Sharma 2006 Prague C and M; not a Barrett diagnosis (histology required); magent does not perform endoscopy",
  "c_cm": 0,
  "m_cm": 0,
  "prague": "C0M0"
}

Client errors (HTTP 400)

Invalid params return 400 without charge. Shared HTTP 402 and 503 meanings: Payments.

Related tools

• LA grading — Apply Lundell 1999 Table 1 Los Angeles classification of oesophagitis and return la_grade (none, A, B, C, or D) from four caller-assigned endoscopic flags.
• EREFS — Sum five caller-assigned Hirano 2013 modified EREFS descriptors (edema 0-1, rings 0-3, exudates 0-2, furrows 0-1 after collapsing original 0-2, stricture 0-1) and return the total (max 8). Does not return activity bands, inflammatory or fibrostenotic subscores, or later 0-9 furrows 0-2 expansions.

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. Unpaid valid requests return HTTP 402 with a base64 PAYMENT-REQUIRED header. HTTP 503 is not a new quote: retry the same PAYMENT-SIGNATURE. Full handshake and shared payment errors: Payments. Stdio MCP: /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.