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

Annotations already declare readOnly/idempotent/non-destructive, so the bar is lower, and the description still adds real context: the return shape is a single number, JDG companies are excluded, and sparse/zero results include a `hint` field. That is meaningful disclosure beyond the structured fields, though result-shape nuance beyond the hint is limited.

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 tight sentences, front-loaded with purpose and return shape, then exclusions and edge-case behavior. Dense and efficient, though domain jargon (JDG, RODO, CEIDG) assumes reader familiarity.

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 29-filter count tool with no output schema, the description covers the essential missing pieces: it explains that the return is a scalar and that a `hint` may accompany sparse counts. Nothing critical for correct invocation is absent.

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% across all 29 params, so the schema carries parameter meaning on its own; the description adds no syntax or format detail beyond it. Baseline 3 is appropriate.

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+resource (count KRS companies) with filter scoping, and immediately distinguishes itself from the list-returning sibling by declaring 'Returns a single number — no company list.' An agent can tell it apart from search_companies without opening either 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?

Gives clear when-to-use context (counting against filters) and an explicit exclusion ('Does not count JDG in this tool') with the reason (CEIDG lives in Compabase, is RODO-gated). It does not name a sibling alternative by name, so it stops short of a 5.

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