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

Annotations already cover the safety profile (readOnlyHint=true, openWorldHint=true), so the description needn't restate them. It adds useful context that the data is a merged, currently-ranked composite across seven index families, which tells the agent what kind of records come back, but it says nothing about pagination limits or result shape beyond what the schema carries.

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?

A single front-loaded sentence stating the action and resource, with the index-family enumeration tightly packed into a parenthetical. It is efficient, though the long parenthetical makes it slightly heavier than necessary.

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 14 fully documented parameters and an output schema, the description needn't explain return values, and its scope statement is accurate. What is missing is guidance on when to prefer this composite search over the sibling numbeo index tools or the facets/item endpoints, which an agent invoking in a large toolset would benefit from.

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 every parameter (q, page, sort, country, and the index threshold filters) is already documented in the schema. The description adds no parameter-level syntax, units, or defaults beyond what is provided there, making the baseline 3 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 (Search) and a well-defined resource (the composite Numbeo cities dataset), and clarifies that it merges all seven index families, which distinguishes it from single-index tools. It does not explicitly differentiate itself from the adjacent datasets_numbeo_cities_facets/item or datasets_numbeo_countries_search siblings, so it falls short of a 5.

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?

The description implies usage by calling the dataset 'composite' and merged 'from the current global rankings of all seven index families', suggesting it is the right entry point when filtering across multiple indices. However, there is no explicit when-to-use, when-not-to-use, or named alternative (e.g., facets or item tools), leaving routing to inference.

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