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

Annotations only declare readOnlyHint and openWorldHint; the description adds substantial behavioral context beyond that — it discloses the exact share fields returned (vklad/splaceno/velikost podílu), that historical members include a removal date, and critically that it returns an empty list rather than an error when the register does not publish owners (most a.s.). That last point is a non-obvious failure-mode disclosure.

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?

It is front-loaded with the core purpose and packs useful detail into a few dense sentences, each earning its place. It runs slightly long with parenthetical Czech terminology, but nothing is redundant or wasteful.

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?

An output schema exists, so return-value structure needn't be explained, and the description still covers scope, data fidelity, edge cases, and intended use. For a single-parameter read tool with annotations and an output schema, nothing an agent needs to call it correctly is missing.

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% and the single ico parameter is fully documented in the schema ('Czech IČO (7-8 digits)'). The description adds no additional syntax or format guidance for the parameter, so the baseline of 3 applies.

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 names a specific verb and resource ('Get owners of a Czech company') and precisely distinguishes the two owner types it returns (společníci for s.r.o./v.o.s./k.s. and akcionáři for a.s.), which cleanly separates it from the sibling get_statutaries. An agent can identify the exact scope without opening the schema.

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?

It gives a strong use case ('Essential for KYC/AML due diligence on ownership structure') and draws scope boundaries by excluding scoring, risk assessment, and cross-company aggregation. However, it never explicitly names or routes to alternatives such as get_statutaries or get_history, so the when-vs-alternative guidance is implied rather than stated.

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