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

With no annotations, the description carries the full burden. It discloses what the result set contains (priced cities plus distance and travel band), implying a read-only lookup, but says nothing about ordering, exhaustiveness, pagination, or whether the 'current operator base' is a fixed or caller-dependent reference point.

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 zero filler, and the content of the listing is front-loaded before the usage trigger. Slightly awkward as a sentence fragment, but nothing is wasted.

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 zero-required-parameter read tool with no output schema, the description covers both what comes back and when to reach for it. The only meaningful omission is the region filter mentioned in the schema, which the description ignores entirely.

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% and the single region parameter is fully documented with an enum, so the schema does the work. The description never mentions filtering by region, so it adds no meaning beyond what the schema already provides; 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 description names the resource (cities) and the specific returned attributes (priced status, distance from the current operator base, travel band), which is enough to distinguish it from list_missions and quote_mission. It lacks an explicit verb like 'list', but the noun-phrase form still conveys a read operation unambiguously.

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 a concrete trigger: call this when the user names a city that cannot be matched, to pick the nearest listed anchor. That is stronger than generic context, but it names no exclusion against the siblings (city_missions, list_missions), so an agent must infer that those serve different needs.

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