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

Annotations already declare readOnlyHint and idempotentHint, so the safety profile is established. The description adds meaningful behavioral context beyond those hints: the exact scope ('directly bookable'), the two data fields returned (home count and maximum sleeping capacity), and that it is a coverage lookup rather than a search.

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 purposeful sentences with no fluff. The core statement of what is returned is front-loaded, followed by a clear usage trigger. Every sentence earns its place.

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, idempotent listing tool, the description is complete. It tells the agent what data will be returned, the scope of the data, and the exact circumstances under which the tool should be invoked. No output schema exists, but the return shape is adequately described.

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 description has no parameter semantics burden. Baseline 4 is appropriate; the description correctly focuses on the response content instead of over-explaining inputs.

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 the tool's function: enumerating cities where Luxury Lodging has directly bookable homes, with key aggregate data (home count, max group size). It also distinguishes itself from the sibling search-oriented tools by framing this as a destination-coverage listing.

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 explicitly says when to use it: when the guest has not named a place, or to verify a destination is covered before searching. It does not explicitly name sibling alternatives or state when not to use it, so it misses the full exclusion guidance needed for a 5.

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