mcp

calculate_iuc

Estimate the Portuguese annual road tax (IUC, Imposto Único de Circulação) for a car — the yearly tax an owner pays — from the official IUC table. A maintained estimate; confirm on the official AT simulator. Needs engine displacement (cc), CO₂ (g/km), fuel and registration year.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "year": "<year>"
    },
    "name": "calculate_iuc"
  }
}

Input Schema

Name	Required	Description
`cc`	No	Engine displacement in cm³, e.g. 1950 (not needed for goods vehicles)
`co2`	No	CO₂ emissions in g/km, e.g. 130 (passenger/motorhome only)
`fuel`	No	Fuel: petrol, diesel, hybrid, hybrid_diesel (diesel MHEV/HEV), phev, electric (irrelevant for heavy goods/buses)
`year`	Yes	First registration year, e.g. 2016
`axles`	No	Heavy rigid goods ≥12t: axles (2/3/4).
`config`	No	Heavy goods ≥12t: rigido or articulado (tractor+trailer).
`peso_bruto`	No	Gross weight (kg). REQUIRED for goods vehicles (van_10/commercial_*/pesados_mercadorias): their IUC is weight-based (Cat C/D).
`suspension`	No	Heavy goods ≥12t: driven-axle suspension.
`utilizacao`	No	Goods use: particular (Cat C, default) or publico/rental (Cat D).
`vehicle_type`	No	Category (default passenger). Goods van → van_10/commercial_*; heavy goods >3500kg → pesados_mercadorias; bus → pesados_passageiros; motorhome → autocaravana; motorcycle → motorcycle.
`tractor_axles`	No	Articulated ≥12t: tractor axles (2/3).
`trailer_axles`	No	Articulated ≥12t: trailer axles (1/2/3).
`regiao_autonoma`	No	Used exclusively in Açores/Madeira → −50% IUC (Cat C/D).

Schema Changelog

Changes observed during successful MCP inspections.

AddedSep 15, 2026

TDQS

B3.4/5.0

Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden. It does disclose that the result is an estimate, that it is maintained, and recommends official confirmation — a genuine caveat. However, it does not disclose conditional parameter dependencies (e.g., axles/config only for heavy goods) or the output form, relying on the schema to carry that. Given the honest 'estimate' disclosure, a 3 is fair.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences with no filler. The purpose is front-loaded, the estimate caveat is integrated, and the required inputs are listed compactly. Every sentence earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

This is complex (13 parameters, no output schema, no annotations) and the description remains minimal. It doesn't state what the tool returns (the estimated tax value), doesn't mention the breadth of vehicle types, and doesn't flag that only 'year' is required while others are conditional. An agent handling a van or heavy-goods query would not be prepared by this description.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3. The description repeats parameter names (cc, CO₂, fuel, year) but adds no extra semantics beyond what the schema already documents. It does not explain which combinations are required for different vehicle types; the schema handles that. Thus no credit above baseline.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb ('Estimate') and a unique resource ('Portuguese annual road tax IUC'), and names the official IUC table as the source. It distinguishes the tool from the sibling calculate_isv, which targets a different tax, without needing to open schemas. The phrase 'for a car' is a minor simplification, but the core purpose is unmistakable.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives no explicit guidance on when to choose this tool over siblings such as calculate_isv, request_import_quote, or estimate_resale_value. It implies you need cc, CO₂, fuel, and year, but does not state the use cases for van/heavy-goods/motorcycle variants nor any exclusions. The only advisory ('confirm on the official AT simulator') is about reliability, not selection.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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