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

Annotations cover only the safety profile (readOnly/idempotent/non-destructive), and the description goes well beyond that: it discloses that addresses are rounded when the host keeps them private, decodes the `bookable` flag, explains the three `bookingMode` outcomes from the guest's perspective, and clarifies that `cancellation.terms` is the level promise while `custom` requires reading `note`. These are exactly the behavioral details an agent cannot infer from annotations or schema.

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?

Front-loaded with the resource identity, then packed with parenthetical clarifications; nearly every clause carries usable information. It is a single dense block rather than a poorly organized one, though the bookingMode sentence could be tightened.

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 carries the full burden of describing the return payload and does so field-area by field-area (identity, location, capacity, amenities, rules, times, cancellation, photos, price). Combined with the flag semantics, an agent can call it and interpret the result without further docs.

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?

Schema coverage is 100% and both parameters (slug, locale) are documented in the schema, including where the slug comes from. The description adds no parameter-level detail such as slug format constraints or locale fallback behavior, so the baseline 3 applies.

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 opening clause 'One holiday rental: what it is, where ... capacity, amenities ...' states a specific resource (a single rental listing) and enumerates the payload, which naturally separates it from the multi-result search_stays and the action tools (get_quote, create_checkout). It never names a sibling or explicitly contrasts itself with them, so it falls just short of a 5.

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 gives a concrete usage rule: when `bookable: false`, 'the guest contacts the host; do not quote or prepare a checkout for it', which steers the agent away from get_quote/create_checkout in that case. It also explains when each `bookingMode` applies. What is missing is a positive routing statement (e.g. 'use after search_stays to fetch full details').

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