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

Annotations already declare this as read-only, open-world, and idempotent, so the safety profile is covered. The description adds useful return-field context, but it does not disclose that the default compact form may omit photo and tour links (per the expand parameter). It does not contradict the annotations, but it misses an opportunity to clarify response-shape behavior for the default call.

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 one efficient, front-loaded sentence that packs resource, returned fields, and lookup modes without filler. It is slightly noun-phrase-like rather than an imperative sentence, but every clause carries useful information.

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 no output schema, the description usefully enumerates the primary return fields: name, address, description, amenities, unit and floor-plan counts, rent range, and photos. It also explains both parameterization options. The main missing piece is an explicit note about the compact vs. expanded response controlled by the expand parameter, though the schema covers that.

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%, so the baseline is 3. The description adds value beyond the schema by stating that buildingId must come from a forRent search row with resultType propertyGroup and that lat/lng can serve as an alternative identifier. This helps the agent understand the relationship between the parameters without reading every schema detail.

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 identifies the resource (a rental building) and the return fields, and it specifies the two lookup modes: buildingId or lat/lng. It does not use an explicit verb like 'get' or 'retrieve', but the 'by buildingId ... or by lat and lng' construction makes the action clear and distinguishes this from generic property or search tools.

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 concrete context for when to call the tool: after obtaining a buildingId from a forRent search row with resultType propertyGroup, or when lat/lng are available. It does not name alternative sibling tools or explicitly state when not to use it, but the source-of-buildingId guidance is strong enough for an agent to route correctly.

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