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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), yet the description adds substantial behavioral context beyond them: the period-consistency guarantee for all money fields, the Ohlson/RIM basis of estimated_value, the MF white-list provenance of vat, and the RODO-driven NIP-lookup edge case returning a CEIDG/JDG firm.

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?

Content is front-loaded on what the response contains and every clause carries information, but the opening is a dense, parenthetical-heavy run-on and the period-consistency point is stated twice ('...for one latest filed period' and 'All money fields in this response are that same period').

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 carry the return contract, and it does: it enumerates the field groups, defines the monetary-estimate methodology, discloses the VAT data source, and flags the excluded balance-sheet items. An agent has enough to call and interpret the tool correctly.

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 the baseline is 3, but the description adds meaning beyond the schema by explaining that a NIP lookup can return a CEIDG/JDG sole proprietorship when it has a public contact email. It does not, however, explain precedence when multiple identifiers are supplied.

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+resource (company registry profile plus headline financials) and enumerates the exact fields returned (revenue, profit, PKD, address, vat, KRS changes). It actively distinguishes itself from the most confusable sibling by stating what it excludes and pointing to get_financials.

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 an explicit when-not and a named alternative: 'Does NOT include balance-sheet line items... For those or earlier years, use get_financials.' That is strong routing guidance, but it says nothing about when to prefer this over the many other get_company_* siblings (people, beneficiaries, articles, etc.), leaving that inference to the agent.

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