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

Beyond the readOnlyHint annotation, the description discloses important behavioral traits: it returns 'structuredContent ownership tree plus markdown summary,' and that 'physical persons expose name and birth year only, never full birth date or address.' These additions give the agent a clear picture of output format and privacy constraints, going well beyond what annotations provide.

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 concise and front-loaded: the first sentence states the primary purpose, the second notes the free/anonymous nature, and the third covers return format and privacy. Each sentence adds distinct value without unnecessary fluff, making it easy to scan quickly.

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?

Although there is no output schema, the description sufficiently explains the return format ('structuredContent ownership tree plus markdown summary') and important privacy redactions (birth year only). It also clarifies the scope ('direct and upstream') and the data source semantics, making it complete for an agent to understand what the tool does and what to expect.

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 input schema provides full coverage of both parameters ('ico' and 'max_depth') with clear descriptions. The tool description does not add additional parameter-level semantics beyond what is in the schema; it only mentions 'member_ico edges' in the context of the tool's function, which is not a direct explanation of the parameters. Thus, 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 clearly states the tool's function with a specific verb ('Look up') and resource ('direct and upstream Czech VR owners'), including details on the type of ownership roles ('spolecnik/akcionar') and relationship edges ('member_ico edges'). This distinguishes it from sibling tools like get_statutory_chain or person_companies, which focus on different corporate aspects.

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 on when to use the tool: for looking up Czech VR owners with real active shareholding roles and company-to-company member_ico edges. It also notes it is a 'Free anonymous tool,' implying no authentication is required. However, it does not explicitly name alternative tools or state when not to use this one, 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.