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

Beyond the readOnly/idempotent annotations it discloses substantive behavior: the nightly rate is a cached value up to 6 hours stale and not a price, photos are truncated to 5 with imageCount carrying the true total, only the 3 newest reviews are returned and are quoted guest text, and street address plus coordinates are deliberately withheld. These truncation and staleness caveats are exactly the kind of detail an agent cannot infer from the 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?

The content is packed into two long sentences that are dense but front-loaded with the resource and its fields before the caveats, so the most important information lands first. It is close to a field dump, but every clause carries a real constraint, so nothing is obviously wasteful.

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 and only two simple parameters, the description carries the full burden of explaining return values and does so field by field, including truncation limits and omitted data. An agent can call this tool and correctly interpret its response without further documentation.

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 each of the two required parameters is already documented in the schema as coming from list_sites and list_properties respectively. The description adds no additional meaning about siteSlug or propertyId, so the baseline of 3 applies; the intake path is already fully covered by structured data.

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 opens with a specific verb and resource ('Returns one unit') and enumerates the fields returned, so the agent knows exactly what it retrieves. It implicitly contrasts with list_properties by being singular, but never names the sibling explicitly, and the title ('Get one unit's details') differs from the name get_property, leaving a small ambiguity about whether it is a unit or a property record.

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 clear usage boundary for the rate field: indicativeNightlyRate is a cache-derived guide and 'get_quote returns the price for dates', which routes the agent to the correct alternative for pricing. What it does not state is when to call this versus list_properties for a broader sweep, so guidance is strong on one axis but not exhaustive.

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