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

Annotations already signal read-only, idempotent, open-world behavior. The description adds valuable behavioral context: ~10-second refresh cadence, the community receiver network, the 1,000-aircraft per-call limit, and open access. This goes beyond what the annotations convey and gives the agent a realistic execution model.

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?

The description is front-loaded with the core purpose and return fields, then moves to data freshness, parameters, limits, and access. It is compact and well organized, though a bit of information such as the source URL is somewhat redundant with the tool title and domain.

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 low-complexity, read-only query tool with a complete input schema and an output schema present, the description covers purpose, returned fields, update cadence, source, parameter constraints, call limits, and authentication requirements. Nothing critical for correct invocation is missing.

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?

The input schema already describes all five parameters, so the baseline is 3. The description adds extra operational guidance by specifying decimal degrees and advising smaller bounding boxes for dense airspace, which is genuinely useful beyond the schema. It is not a large addition, but it raises the score slightly.

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 uses a specific verb and resource: retrieve real-time ADS-B state vectors for all aircraft within a geographic bounding box. It enumerates the exact returned fields, which makes the tool's scope concrete and distinguishes it from sibling tools like states_country or aircraft_track by the bounding-box qualifier.

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?

It clearly establishes when to use the tool: for live aircraft inside a lat/lon bounding box, and it gives operational guidance such as using a smaller bbox in dense airspace and noting that no authentication is needed. It does not explicitly contrast this tool with alternatives like states_country, so it falls short of a 5.

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