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

Annotations already declare this as a read-only, idempotent, non-destructive, open-world operation. The description adds meaningful context beyond that: the tool returns a vocabulary of slugs and English names, and the slugs are valid only for escort searches in search_listings.

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 short sentences, front-loaded with the primary purpose and followed by the downstream usage note. There is no redundant or filler content.

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, read-only vocabulary tool with no output schema, the description is complete: it states what the tool lists, what fields are returned, and how the returned slug should be used. Nothing essential for correct invocation 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?

The tool has zero parameters and an empty object schema, so there is no parameter semantics to document. The baseline of 4 applies because the description cannot add meaning beyond an empty schema.

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 uses a specific verb ('List') and resource ('service vocabulary of escort listings') and explicitly names the output fields ('slug and English name'). This distinguishes it from sibling vocabulary tools like list_cities and list_countries, which cover different filter dimensions.

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 states the downstream use clearly: 'Use a slug as `service` in search_listings (escort searches only).' This tells the agent when the returned values are relevant, though it does not explicitly contrast calling this tool with calling the sibling list tools.

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