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

Annotations already mark this as read-only, open-world, idempotent, and non-destructive; the description adds value by noting 'keyless, CC0 open data' (no auth needed) and by clarifying that relationships without GLEIF filings are reported as 'none reported' rather than errors. It also explains the node contents, which are not visible in annotations.

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 dense and front-loaded with the core action and data source; the caveat about 'none reported' and the node-field detail both earn their place. It is slightly long and structured as one continuous sentence, which mildly reduces scannability.

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?

With no output schema, the description carries the burden of explaining return values, and it does so semantically: parent, ultimate parent, children list, total count, and per-node LEI/name/jurisdiction. It also covers auth and missing-data behavior. It lacks exact response shape or invalid-query handling, but for a two-parameter read-only tool this is adequate.

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 the baseline is 3. The description restates that the query can be a company name or LEI and contextualizes the output, but it adds no parameter-specific semantics beyond the schema. children_limit's default, max, and behavior are already fully documented in the schema.

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 opens with a specific verb and resource: 'Map a company's corporate family tree from the GLEIF relationship register.' It concretely lists the outputs—direct parent, ultimate parent, direct children/subsidiaries, and total subsidiary count—which clearly distinguishes it from similar-looking siblings. The explicit ownership questions further clarify what the tool is for.

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 description provides clear context: it answers 'who ultimately owns this company?' and 'what does this company own?' and frames the tool for due-diligence and beneficial-ownership work. It does not explicitly name alternatives or give when-not-to-use guidance, so it stops short of a 5.

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