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

Annotations already declare read-only, idempotent, and non-destructive behavior. The description adds that the vocabulary is 'current' (implying it may change over time) and lists what it contains, giving the agent a clear idea of the return content. It does not discuss limitations or side effects beyond this, but with annotations covering safety, this is adequate.

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?

The description is two sentences, front-loaded with the action and content list. The second sentence gives a clear usage directive. Every word earns its place, with no redundancy or fluff.

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?

Given the tool's simplicity (no parameters, no output schema), the description is complete: it defines what the tool returns, the content categories, and when to use it. The annotations cover safety, and the description adequately bridges to using it with sibling search tools.

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?

There are 0 parameters, so the baseline is 4. The description does not need to explain parameter syntax, and the empty schema is fully consistent. No extra information is needed.

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 clearly states a specific action ('Return the current structured search vocabulary') and lists the content types (arrival weeks, durations, amenities, filters, price sorting, entity types, language subdomains). This distinguishes it from sibling tools like list_accommodations or search_apartments, which are about searching/listing rather than providing vocabulary.

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 provides clear context for when to use the tool: 'Use this first when you need valid parameter values.' This implies a sequential workflow before building a search, but it does not explicitly name alternative tools or state when not to use it, so it misses the full marks.

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