List EU VAT rates

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

No annotations provided, so description carries full burden. It discloses data source (EU Commission TEDB), update frequency (daily), and that it's free with no API key required. However, it could explicitly state it's read-only and has no side effects.

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?

Three sentences: first states purpose, second provides usage guidance, third adds data source and constraints. No wasted words, front-loaded with most important information.

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?

Given simple tool with no parameters and no output schema, description is nearly complete. It covers purpose, usage, source, update frequency, and cost. Minor gap: does not describe return format (e.g., map of country to rates), but output schema is absent so that expectation is low.

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?

Zero parameters, so description need not add parameter meaning. Schema coverage is 100% (empty). Baseline for 0 parameters is 4, and description correctly focuses on tool behavior without parameter clutter.

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?

Clearly states it returns current VAT rates for all EU member states plus Northern Ireland. Distinguishes from sibling get_country_vat_rates by noting preference for single country queries.

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?

Explicitly tells when to use (overview, comparison, 'all EU VAT rates') and when not to (single country, prefer get_country_vat_rates). Provides clear guidance on alternatives.

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