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

Annotations cover the safety profile (readOnly, idempotent, openWorld, non-destructive), and the description adds real behavioral context on top: cost limits (2 units), API key requirement, that ownership covers only signals and not beneficial owners, that companies without an LEI show no links, and that no people/director links are returned.

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?

Front-loaded with the purpose, then clearly labeled Inputs / Returns / Limits blocks. Each sentence carries distinct information; none is filler or restatement.

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?

Even though an output schema exists, the description pre-empts the key questions for this kind of traversal tool: what nodes and edges mean, evaluation cost, auth requirements, and the LEI/people coverage gaps that would otherwise surprise an agent.

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 already 100% for both parameters, and the description reinforces the entity_id format example and the depth 1-or-2 constraint. The parent_of kind and edge fields it mentions describe returns rather than inputs, so it adds only modest input-side value, landing at the baseline-plus level rather than degrading.

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 and resource ('Show a company's group: its parent and child companies from GLEIF') with the edge semantics pinned down. It explicitly distinguishes itself from resolve_company by naming the sibling it is not.

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?

Gives both when-to-use ('Use it to map a company's group') and when-not ('Don't use it to look a company up') plus the prerequisite step ('call resolve_company first for its entity_id'). Nothing is left to inference.

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