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

Annotations cover the safety profile (readOnlyHint, openWorldHint), so the bar is lower, but the description adds genuine behavioral context beyond them: a credit cost of 1 per record with a minimum of 2, plus the advice to keep page_size minimal. It does not disclose pagination caps or the result shape, but the cost model is a real disclosure.

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 sentences, zero waste, front-loaded with what the dataset is before the cost caveat and the sibling routing. Each sentence earns its place.

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 no explanation, and full schema coverage handles parameters. The description supplies dataset composition, cost model, and sibling routing, which is nearly complete for a search tool; only edge behaviors like the 10000-result cap interplay are left implicit.

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 all 14 parameters are already documented in the schema, making the baseline 3. The description reinforces page_size's cost implication but adds no syntax or format detail beyond the schema.

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 (Search) and resource (composite stored Numbeo city dataset), and clarifies scope: records combine seven index families and include only cities ranked by at least one. It distinguishes itself from datasets_numbeo_countries_search by explicitly noting that sibling covers national records.

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 routes the agent: use datasets_numbeo_cities_facets to inspect filters and datasets_numbeo_countries_search for national records. This gives clear alternatives with their conditions. It stops short of stating when this tool should NOT be used (e.g., single-city lookups via datasets_numbeo_cities_item).

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