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

Annotations already cover the safety profile (readOnly, idempotent, closed-world, non-destructive), so the bar is lower. The description adds genuine value beyond them by disclosing the return semantics (median CZK/m² from realised land-registry sales) and the aggregation behavior (a borough returns its districts, a street returns the districts it runs through). It stops short of noting data recency, coverage limits or what happens for an unknown locality.

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 and segmented with pipe separators into use / do-not-use / scope blocks, which is easy to scan. However, the entire block is duplicated verbatim in Czech and English, roughly doubling length for content that the jazyk parameter already governs.

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 two-parameter read tool with no output schema, the definition covers purpose, exclusions, aggregation semantics and the return metric. An agent has everything needed to select and invoke it correctly without further context.

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 documents both parameters, including locality formats and diacritics/case tolerance. The description adds no parameter-level meaning beyond what the schema states, so the baseline of 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: returns the median CZK/m² price level for apartments in ONE Prague locality, sourced from realised sales in the Czech land registry. It also names the scope granularity (district, borough or street), which cleanly separates it from the per-apartment and multi-locality 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?

Explicit when-to-use ('user asks about the price level in ONE Prague locality without a specific apartment') plus an exhaustive when-not-to-use list that routes each excluded case to a named sibling (odhad_ceny_bytu, srovnani_ctvrti, top_ctvrti_praha, overeni_ceny_inzeratu) and even splits by property type (domy, pozemky). Nothing 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.