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

With no annotations present the description carries the full burden, and it delivers: it discloses the GDPR-driven field-level reduction for natural persons (GUS type F/LF) and civil partnerships, spelling out exactly which fields are and are not returned (no REGON, address, units, or dates) and the enum values for forma and status. This is unusually rich behavioral disclosure and points to the source of the full record.

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 purpose and coverage claim are front-loaded, and the GDPR caveat follows in a dense but useful second sentence. It is somewhat list-heavy with parentheticals, but nearly every clause (coverage scope, exception fields, alternative source) carries information an agent needs.

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?

There is no output schema, so the description must explain returns — and it does, per entity type, including what is omitted for natural persons and where the full record lives. For a one-parameter lookup with no annotations, nothing needed 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% — the single nip parameter is already documented as a 10-digit Polish tax ID. The description reinforces that NIP is the sole lookup key but adds no format, validation, or edge-case detail beyond the schema, so the baseline 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?

States a specific verb and resource ('Look up entity data in the REGON register ... by NIP') and enumerates the returned fields (REGON number, name, legal form, address). It also scopes coverage explicitly ('Covers ALL entities, including sole proprietors that are not in the KRS'), which lets an agent distinguish it from NIP/KRS-oriented siblings.

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?

Clear contextual guidance: use this for REGON data by NIP, and it points to the GUS REGON search (privacy.officialSource) when the full entry is needed. It stops short of naming or contrasting the sibling tools (sprawdz_nip, sprawdz_lista_nip, sprawdz_vies), so routing between siblings 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.