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

Annotations already declare readOnlyHint=true and destructiveHint=false, yet the description still adds real value: the signed propertyRef requirement, the fallback semantics when dates/guests are omitted, and the crucial caveat that the returned price is an estimate subject to host confirmation rather than a bookable offer. That caveat is exactly the kind of behavioral context annotations cannot carry.

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?

Three sentences, front-loaded with the action and resource, then the prerequisite, then fallback semantics, then the estimate caveat. Every sentence carries information the agent cannot get from the schema or annotations.

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 six-parameter pricing lookup with no output schema, the description covers the prerequisite, the omitted-parameter fallback, and characterizes the return as an estimate pending host confirmation. Missing only coverage of currency and the childrenAges array semantics.

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 description coverage is 0%, so the description must compensate and it does so partially: it explains propertyRef (must be the signed ref from search), and the semantics of checkinDate/checkoutDate/adults in one sentence about retaining the original search stay. currency and childrenAges receive no explanation anywhere, leaving the agent to guess at currency behavior and child-age sensitivity.

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?

States a specific verb (refresh) and precise resource (availability and estimated full-stay price for a furnished home from search results). It partially separates itself from the hotel siblings by clarifying this is not a hotel room offer, but it never names get_hotel_offers/get_home_details as alternatives.

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?

"selected from search results" establishes the prerequisite that the item must come from a prior search, and "Omitted dates or guests retain the original search stay" tells the agent it can call without re-specifying the stay. No sibling is named for the contrasting case (full hotel offers, property details), so routing is implied rather than explicit.

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