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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the safety profile is covered. The description adds real value beyond that: zero cost in Pro mode, and the caveat that PKD-division listings read nightly facts and may be unavailable before those facts are built. These are genuine operational traits the schema cannot express.

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?

Purpose is front-loaded in the first clause, followed by usage, cost, availability caveat, and an example — every sentence carries information. It is dense but slightly sprawling for a single paragraph; splitting the caveat would improve scanability.

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?

With an output schema present, return values need not be described. The description covers page size, the page parameter, all filter dimensions, the cost model, and the main failure mode, leaving nothing an agent needs before invoking it.

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 coverage is 100%, so the schema already documents each of the five parameters. The description still adds the non-obvious cross-field constraint (letter only with city) and a concrete example payload {"pkd_division": "62", "city": "Kraków", "page": 2} showing how filters combine.

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 concrete action and resource: returns a page of 100 companies from the site's list, with the exact ordering dimensions (city, two-digit PKD division, legal form, or initial letter). It is immediately distinguishable from search_companies, which is named and reserved for name lookups.

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?

Explicitly says to use this for browsing companies within one city, industry, or legal form, and explicitly routes name-based lookup to search_companies. It also encodes the cross-parameter rule that the letter filter works only together with city.

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