DEVELOPER + AGENT INTERFACE

One contract.
Receipts included.

The web calculator, HTTP API, and MCP tools share the same schemas, publication decisions, missing-data errors, and metering boundary.

JSONEffective-datedRead-only MCP

HTTP CONTRACT

A total exists only when the evidence is complete.

Requests must include entry date, origin, destination, mode, transaction context, line-level tariff codes, values, and currencies. A missing material fact produces a typed error.

REQUEST

POST /api/estimate
Content-Type: application/json

{
  "entry_date": "2026-08-03",
  "origin_country": "BR",
  "dispatch_country": "BR",
  "destination_country": "US",
  "destination_region": null,
  "transport_mode": "express_courier",
  "transaction_type": "commercial_b2c",
  "incoterm": "DAP",
  "settlement_currency": "USD",
  "lines": [
    {
      "line_id": "line-1",
      "destination_tariff_code": "6109100012",
      "description": "Cotton T-shirts",
      "origin_country": "BR",
      "quantity": "1",
      "quantity_unit": "item",
      "unit_price": {
        "currency": "USD",
        "decimal": "50.00",
        "tax_inclusive": false
      }
    }
  ],
  "shipping": {
    "currency": "USD",
    "decimal": "12.00"
  },
  "insurance": {
    "currency": "USD",
    "decimal": "0"
  },
  "other_incidental_costs": [],
  "tax_collection": {
    "pathway": "unknown",
    "ioss_status": "unknown",
    "prices_include_tax": false
  },
  "preference_claim": {
    "mode": "none"
  },
  "fee_mode": "official_only",
  "carrier_charges_scope": "include"
}

CURRENT LOCKED RESPONSE

HTTP/1.1 503 Service Unavailable

{
  "error": "publication_locked",
  "message": "No public calculation release is approved.",
  "grand_total": null,
  "missing_components": [
    "tax", "preferences", "trade_remedies",
    "fees", "official_fx", "carrier_charges"
  ]
}

Calculation

POST /api/estimate

Returns component-level evidence or a structured refusal. Discovery remains separate from metered calculation.

Provenance

sources[] + release_id

Supported components carry official citations, effective time, rule identity, and release provenance.

MCP

calculate_landed_cost

Three read-only agent tools reuse the API boundary. Registry submission and public agent access remain disabled.