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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds the result-cap and radius-scoping behavior ('at most 50', 'within at most 250 nm'), which is useful but partially redundant with the schema's maximums. No additional context about pagination, response shape, or error handling is given.

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 sentence with no filler. The key action and constraints are front-loaded, making it easy to scan.

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?

The description conveys the core function but lacks details about the returned aircraft data, ordering, or units. Since there is no output schema, more context would help, but the tool is simple and annotations cover safety, so basic completeness is acceptable.

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 0%, so the description should compensate. It implicitly references the limit and radius_nm constraints via 'at most 50' and 'within at most 250 nautical miles', but does not explicitly describe lat/lon or explain the parameters. This is insufficient for the four-parameter tool.

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 states a specific verb ('Return') and resource ('aircraft') with explicit constraints ('at most 50', 'within at most 250 nautical miles'). This clearly differentiates it from generic get_aircraft and network_stats siblings, even without naming them.

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?

No explicit usage guidance is provided. There is no mention of when to choose this over get_aircraft or network_stats, but the description's focus on proximity implies it is for nearby-aircraft lookups. This is implied, not stated.

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