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

Annotations already cover the safety profile (readOnly, idempotent, closed-world), and the description meaningfully reinforces the closed-world hint by naming the embedded data sources (GeoNames, UN/LOCODE, OurAirports), which explains why results are limited to a fixed catalog. It stops short of describing result ordering or how 'limit' interacts with matching, but adds real context 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?

A single dense sentence leads with the action and resource set, then the lookup keys, then the intended use case. Every clause earns its place and nothing is padded or repeated.

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?

With no output schema, the description does note that results carry coordinates, and it explains the identifier formats and result kinds an agent will encounter. Missing only minor operational detail (result ordering, how the limit is applied), which is a small gap for a straightforward search tool.

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 100%, so all three parameters are already documented in the schema, including the kinds enum values and the identifier formats. The description repeats the identifier formats (UN/LOCODE, IATA) without adding new semantics such as matching rules, partial-name behavior, or default kind filtering, so the baseline of 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 description names a specific verb (Finds) and enumerates the exact resources covered: cities, sea/inland ports, rail and road terminals, inland depots, border crossings, airports. It also states the lookup keys (name, UN/LOCODE, IATA) and the data provenance, which cleanly separates it from the calculation-oriented siblings.

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 gives explicit usage context: "Use it to fill a leg's from and to," which tells the agent exactly when to reach for this tool. There are no overlapping siblings to disambiguate against, so no exclusions are needed, though a note about resolving unknown place names before calculating would make it complete.

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