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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds that no parameters are needed and that the entire airport set is returned, but says nothing about response size, pagination, or caching — modest added value 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?

Four markdown sections for a zero-required-parameter lookup. The 'What You Get' bullets restate the Overview (coordinates, country codes, names) and the fourth 'When to Use' bullet duplicates the first, so a substantial portion of the text is redundant rather than earning 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?

For a simple enum-style reference endpoint with no output schema, the description adequately conveys the returned fields (codes, names, coordinates, ISO-2 country codes) and that no input is needed. The one unresolved item is how it relates to its near-twin sibling, which matters for correct selection.

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?

There is a single optional timeout parameter with 100% schema description coverage, so the schema already documents it. The description says only 'No parameters required', which is consistent with required=0 but adds no semantics beyond the structured field; baseline 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?

The Overview gives a specific verb and resource — fetch IATA airport codes with names, coordinates, and country data — and the 'What You Get' section enumerates the payload. However, it never distinguishes itself from the near-identical sibling get_data_flights_airports_iatas, so an agent cannot tell the two apart from the description alone.

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 'When to Use' bullets give context (airport searches, location selection, reference data), but they are generic use-case restatements rather than routing rules. With a sibling like get_data_flights_airports_iatas doing essentially the same job, the absence of any when-not or alternative guidance is a meaningful gap.

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