vies_member_state_status

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

With no annotations, the description carries the full disclosure burden; it does convey that this is a real-time status probe over a fixed set of 28 EU member states plus XI, which is useful scope information. However, it says nothing about the response shape (per-country status?), caching/rate limits, or whether partial outages are reported, so key behavioral traits remain undisclosed.

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 front-loaded sentence with zero filler; the scope qualifier ('all 28 EU + Northern Ireland (XI)') is the only extra detail and it earns its place.

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?

There is no output schema and no annotations, so the description is the only source of information about results — yet it never describes what 'availability' looks like per database. For a simple zero-param probe this is nearly adequate, but an agent cannot predict the return structure.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate; baseline 4 applies. The description does usefully clarify that coverage is the full EU-28 plus Northern Ireland rather than a caller-selected subset.

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 ('Check ... availability') and a precise resource ('all 28 EU + Northern Ireland (XI) national VAT databases connected to the European Commission VIES gateway'). It is readily separable from the nearest sibling (vies_validate_vat_batch) because it reports database/service status rather than validating numbers, though it never names that sibling explicitly.

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?

Usage is only implied: an agent can infer this is a health/pre-flight check before running VAT validation, but the description never says when to call it, when not to, or which sibling to use instead. No prerequisites or conditions are stated.

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