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

With no annotations, the description carries the full burden. It helpfully discloses the return fields (legal name, ID, status, address, VAT ID, activity code, source link), implying a read-only lookup, but it says nothing about authentication, rate limits, quota costs, or result completeness/pagination.

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 purpose is front-loaded in the opening sentence, and the country-code sentence and return-field sentence each add distinct value with minimal waste. It is compact and well ordered, though the country-code enumeration is dense.

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?

For a 3-parameter tool with no annotations and no output schema, the description is reasonably complete: it names the data sources and lists return fields. Gaps remain around the undocumented 'limit' parameter and any behavioral constraints (auth, rate limits), which leaves the agent guessing on edge cases.

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 description coverage is 0%, so the description must compensate. It explains 'query' (name or registry number) and richly documents 'country' with per-country identifier mappings (SIREN, org.nr, Y-tunnus, ICO, KRS, LEI/GLEIF), but the 'limit' parameter is left entirely unexplained in both schema and description.

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 states a specific verb and resource ('Look up a company in official European business registers by name or registry number'), which is far more informative than the name alone. It does not, however, differentiate itself from siblings like kyb_check, verify_vat, or verify_eori, so an agent must infer which lookup tool fits which task.

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 implied by the description and the country-code list gives practical context for how to invoke it, but there is no explicit when-to-use guidance, no exclusion of when NOT to use it, and no routing to sibling tools such as verify_vat for VAT verification or kyb_check for onboarding.

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