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

Annotations already declare this a safe, idempotent, read-only, closed-world lookup, so the safety profile is covered. The description adds real context beyond that: prefix-matching semantics (matching on the start of a name) and the fact that the IATA list is much larger than the lounge directory, which explains expected hit behavior. Result ordering and default result count are left to the schema.

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 tight sentences with no filler, leading with what is searched and following with the practical resolution use case. Every clause carries information an agent needs.

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 two-parameter lookup with no output schema, the description covers scope, matching behavior, and downstream purpose. It could go slightly further on what a result row contains (code, city, airport name) and whether results are ranked, but nothing essential to calling it 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?

Schema coverage is 100%, including the limit cap and the example query form, so the schema carries the parameter detail. The description reinforces the code-vs-name-prefix distinction but adds no syntax or matching rules beyond it, making the baseline 3 appropriate.

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 (search) and resource (worldwide IATA airport list) and distinguishes the dataset from the lounge directory, which is a useful scope cue. It does not, however, differentiate itself from nearby siblings like get_iata or list_airports, so an agent must infer the boundary.

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?

Gives clear context for use: look up a code or resolve a city name into the code that get_airport and search_lounges require, which names downstream consumers. It stops short of explicit exclusions (when to use get_iata or list_airports instead).

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