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

With no annotations, the description carries the full burden and does add valuable context: the upstream source (official EC EOS service) and a hard batch cap of 100. It omits any auth requirements, rate limits, or behavior on invalid/partial EORI inputs.

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?

A single tight sentence with the core action and scope front-loaded. Nothing is wasted.

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?

An output schema exists, so return values need no explanation, and the batch input is adequately framed. What remains thin is error/partial-failure behavior for a validation tool, but the essentials for correct invocation are present.

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?

Schema coverage is 0% for the single required 'eoris' parameter, so the description must compensate. It does so reasonably by defining the content (EU EORI numbers) and the cardinality ceiling (up to 100) in one call, though it gives no format/validation rules for individual entries.

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?

States a specific verb (Validate), resource (EU EORI numbers), and scope (up to 100 in one call), which distinguishes it from the single-item verify_eori. However, it does not clarify how it differs from the generic verify_batch sibling, leaving some overlap.

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 parenthetical '(customs / import-export KYB)' implies the domain of use, but there is no explicit when-to-use guidance or routing away from verify_batch/verify_eori. Usage is inferable but not stated.

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