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

Beyond the read-only/idempotent annotations, it discloses that the property is queried live, that the answer is returned verbatim from the booking form, and that a refusal is propagated when a stay cannot be sold. That is genuine behavioral context, though nothing is said about latency or failure modes other than refusal.

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 what the tool returns and then the usage boundary. Slightly wordy in the 'word for word, so the figure is the one its booking form uses' clause, but every sentence carries 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?

With no output schema, the description carries the burden of describing the return value and does so concretely (nights, tax, amount paid at property), plus the refusal case. Nothing an agent needs to call this four-required-parameter tool correctly is missing.

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 property, roomtype, checkin and checkout are already documented in detail, including slug/short-name handling and room-type aliases. The description only restates that these four inputs are required, adding no new meaning, which is the baseline 3 case.

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 states a specific resource and result: the total for one stay at one property, broken into nights, tax and pay-at-property. It also explicitly separates itself from find_rooms by declaring that it returns a price, not availability.

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 positive precondition ('once the property, room type and dates are known') and an explicit alternative with the condition that selects it ('use find_rooms to see which properties have a room free'). No inference is required to choose between the two.

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