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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world behavior, so the safety profile is covered. The description adds genuinely non-obvious semantics: fame rank derives from the single most widely covered production, so rank 1 is not the place with the most credits, and setting sort to productions changes the ordering to production count. That is real behavioral disclosure beyond the annotations.

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?

Two sentences, front-loaded with the core action and scope, followed by the ranking-definition sentence that carries the most decision-relevant information. No filler or restated title beyond the necessary framing.

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 four-optional-parameter list tool with no output schema, the description covers scope, both sort modes, and the definition of the default ranking. Minor gaps remain: it does not indicate what a result entry contains or whether the list is paginated, though the limit parameter bounds size.

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 the baseline is 3. The description still earns extra credit by defining what 'fame' actually means, which the schema only labels as 'Ranking (default fame)', and by clarifying that omitting country yields a worldwide ranking and that productions ordering produces a different (credit-count) ordering with concrete example cities.

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?

The description opens with a specific verb and resource: 'Ranks the places in the atlas', then bounds the scope to worldwide, one country, or one category. This clearly separates it from search-style siblings like search_locations or locations_near, though it never names those siblings explicitly.

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?

Usage is implied rather than stated: the tool is for getting a ranked list of places, optionally scoped by country or category. The description explains what each sort mode produces but gives no explicit when-to-use/when-not guidance or pointer to an alternative tool such as search_locations when a ranked list is not what's needed.

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