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

Annotations already establish readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds the useful scoping detail that only places with studios are returned, but says nothing about ordering, completeness, or what the return shape looks like. With annotations doing the heavy lifting, this is adequate but not rich.

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 tight sentence with no filler. The resource and the 'have studios' constraint are both front-loaded, so the agent can read the scope 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?

For a zero-parameter list tool with no output schema, the description names the three entity types returned and the studio qualifier. It could mention ordering or whether counts are included, but given the annotations and schema simplicity, it is close to complete.

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 there is no parameter semantics burden and the baseline is 4. The description does not need to explain inputs and appropriately stays focused on the returned resource.

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?

Uses a specific verb (List) and a specific resource (countries, regions and cities) with a meaningful qualifier: only places that have studios. It is understandable on its own, though it does not explicitly name how it differs from siblings like list_categories or list_sources.

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?

The description implies this is the discovery tool for geographic coverage, but it gives no explicit when-to-use guidance, no prerequisites, and no alternatives. It also does not clarify whether search_listings should be used when the agent already knows the place.

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