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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the closing "Read-only, idempotent" is largely a restatement. The genuinely additive context is the excluded output domains (no prices, no Cite slugs, no shop offers) and the brand disambiguation ("nakus.sk (NaKus), NOT nakup.sk"), which prevents a real class of misinvocation.

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?

Front-loaded with purpose, then when-to-use, then exclusions, then parameter note — a sensible ordering with no filler sentences. It loses a point for redundancy: the five enum values and the read-only/idempotent traits are already present in structured fields.

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 single-optional-parameter list tool with no output schema, the description covers scope, usage timing, exclusions, and the brand pitfall — enough to call it correctly. The only mild gap is that it doesn't describe the per-segment return shape beyond "with its unit metric."

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% and the schema already spells out the enum values and their meanings (milacikovia=pet, rodina=baby/family, etc.). The description repeats the same enum list without adding format or behavior detail, so it does no work beyond the schema; 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?

"List every LIVE comparison segment on nakus.sk with its unit metric (€/kg, €/kus...)" gives a specific verb, a precisely scoped resource (live segments only), and the shape of what comes back. It is clearly distinguishable from siblings like search_cite_answers or get_unit_price, which deal with prices/answers rather than the segment catalog.

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?

"Use FIRST when the user asks what categories NaKus covers, which metric a category uses, or before searching if you are unsure whether a product type is in scope" states exactly when to reach for this tool. The negative guidance ("Does NOT return prices, Cite slugs, or shop offers — next call search_cite_answers") routes the agent to the correct alternative when this tool is the wrong choice.

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