uk_duty_calculator

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

Annotations already declare readOnly and idempotent. The description adds valuable behavioral context: it uses live GOV.UK data, calculates CIF value, applies duty rate, then VAT. This goes beyond annotation basics.

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

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

The description is front-loaded with the purpose, followed by a breakdown of calculation steps and a bulleted list of use cases. It could be slightly more concise, but it is well-structured and efficient.

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

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

The tool has no output schema, so the description should explain what the tool returns. It mentions 'estimate duty and VAT' but does not describe the output structure (e.g., duty amount, VAT amount, total). This is a significant gap for selecting the tool.

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

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

All 6 parameters have schema descriptions (100% coverage). The description adds meaning by explaining how they are used: CIF from goods+freight+insurance, then duty, then VAT. This connects parameters to the calculation flow.

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

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

The description clearly states 'Estimate UK import duty and VAT for any commodity code,' which is a specific verb+resource. It distinguishes this tool from sibling calculators (e.g., adr_exemption_calculator, cbm_calculator) by focusing on duty and customs for UK imports.

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

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

The description explicitly lists four use cases for when to use the tool (estimate import costs, check duty rates, compare landed costs, determine preferential rates). It does not include negative guidance or alternative tools, but the context is clear enough.

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