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

Annotations already establish readOnly, idempotent, open-world, and non-destructive behavior. The description adds useful context beyond that by naming GLEIF and national registers as sources and by noting that UBO candidates appear only where the register publishes them, which sets expectations about coverage.

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 a single tightly written sentence with zero waste. The most important information, the returned control chain and UBO candidates, is front-loaded.

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 read-only retrieval tool with a fully documented schema and rich annotations, the description is largely complete: it states what is returned, the data sources, and the main UBO availability caveat. It is slightly thin on return structure and on how the optional identifier parameters should be selected, but no output schema exists to carry that detail.

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 100%, so all four parameters are already documented in the schema. The description adds no parameter-level meaning, such as guidance on choosing LEI versus name/country/org_number, so the baseline of 3 is appropriate.

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 uses a specific verb and resource: it returns the control chain from ultimate parent through subsidiaries, plus UBO candidates. The scope is clear and detailed enough to distinguish it from generic profile or company-search siblings, although it does not name or route against those siblings 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?

There is no explicit guidance on when to use this tool versus alternatives such as get_profile or resolve_company. The purpose implies that it is for ownership/UBO retrieval, but the description gives no when-to-use, when-not-to-use, or input-choice guidance.

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