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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and closed-world, so the safety profile needs no repetition. The description still adds real value by pinning the data window to the last completed day (i.e., not live) and naming the upstream source, Atmy Data Hub.

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?

One sentence, front-loaded with the resource and ranking key, with the ordering note appended where it is most useful. No filler or restated field names.

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 5-parameter tool with no output schema, the description covers the core question (what is ranked, over what period, in what order) but leaves the return shape, units, and behavior on an unrecognized country to inference. Adequate, not complete.

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 60%: country, lang and settlements are already documented in the schema, so the description only meaningfully reinforces the order values ('most polluted or cleanest first'). The limit parameter (min 1, max 50, default 10) is never explained in either place.

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+resource+scope: cities within a country ranked by daily PM2.5 for the last completed day, with an explicit ordering dimension. That is enough to tell it apart from get_air_quality (single place) and search_cities (lookup), 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 only implied: the 'last completed day' framing suggests a retrospective snapshot rather than a forecast or live reading, which implicitly rules out get_city_forecast. There is no explicit statement of when to pick this over get_air_quality_history or what happens for an unknown country.

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