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

The description adds substantial behavioral context beyond the annotations: RIK marks the data as informative rather than authoritative, there is no live per-record API, the tool reads the public company page live per request, data_as_of reflects RIK's last-updated date for this section, and removal requests can cause records to be silently withheld and counted. This is exactly the kind of source, freshness, and limitation information an agent needs.

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 front-loaded with the core purpose and returned fields, then adds source and caveat details. It is dense and somewhat long, but every sentence contributes useful context about authority, freshness, or removal handling.

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?

Given the lack of an output schema, the description does a thorough job: it names the returned fields, the data source, the freshness indicator, the authority caveat, and the removal-request behavior. An agent has enough information to invoke the tool correctly and interpret its results.

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 both parameters are already well documented in the schema, including the recommendation to use ee_company_search for partial names or pass registry_code directly. The description reinforces that lookup can be by registry code or exact current name but does not add meaningful new parameter-level semantics beyond 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 states a specific verb and resource: it retrieves an Estonian entity's beneficial owners from the e-Business Register by registry code or exact current name. It also enumerates the returned fields (owner name, date of birth, nationality, control manner, holding start date), making the tool clearly distinct from general company lookup or search tools.

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 gives clear usage conditions: identifier by registry code or exact current name, and it explains that data comes from RIK's public company page live per request. However, it does not explicitly name alternatives such as ee_company or ee_company_search in the description itself; that routing guidance appears only in the schema parameter description.

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