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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description does add one genuinely useful behavioral fact — the list is a derived subset (only places that have hospitals), not a complete geography — but says nothing about ordering, return shape, or whether results are cached/static.

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 front-loaded sentence with no filler. The resource and its scoping constraint are both stated immediately.

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 is the only place an agent could learn the return shape — whether results are flat strings, hierarchical country/region/city objects, or include codes — and it does not say. For a zero-param list tool this is adequate but leaves the return format undefined.

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 tool takes zero parameters, so the schema-baseline of 4 applies. The description adds nothing on parameters, but there is nothing to add — invocation requires no arguments.

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 ('List') plus a precisely scoped resource ('countries, regions and cities that have hospitals'). The hospital-derived scope distinguishes it clearly from sibling listers such as list_categories and list_sources without needing to open any schema.

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?

Usage is only implied: an agent can infer this is the lookup for valid geographic filter values, since the returned set is constrained to places with hospitals. There is no explicit statement of when to use this versus search_listings or get_listing, and no exclusions.

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