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

Annotations already cover read-only, idempotent and closed-world traits, and the description adds genuinely new context: results are limited to the public register, identifiers are person_id rather than PESEL, and the call consumes quota like the 'firma' tool. That quota signal is behavior the annotations do not convey.

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?

Three short sentences, front-loaded with what is returned, then the identifier constraint, then the quota note. No filler; slightly dense phrasing ('Zużywa pulę jak firma') is the only minor friction.

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?

For a one-parameter read tool with no output schema, the description tells the agent what entity is returned and which identifier field to expect, plus the cost implication. Minor gaps remain around the empty-result case, but nothing essential for correct invocation 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?

There is a single parameter with 100% schema description coverage, so the schema already explains the KRS format and example. The description adds no further meaning about the krs argument, leaving this at the baseline.

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?

Names a specific resource (beneficial owners of a company from the CRBR) and implies retrieval keyed by company, which is clearly distinct from siblings like finanse or sprawozdanie. It stops short of explicitly contrasting itself with 'firma', the nearest sibling, so a 5 is not warranted.

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?

'Osoby wyłącznie w zakresie rejestru publicznego' and 'Zużywa pulę jak firma' implicitly tell the agent this is a scoped, quota-costly lookup, which informs when to call it. However, no explicit when-to-use/when-not or named alternative (e.g., use 'firma' for other company data) is given.

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