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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint, so safety is covered. The description adds useful behavioral context beyond that: a quote is non-committal and precedes booking, and it discloses that discounts and vouchers are factored in and that an 'amount payable now' (deposit-style) figure is returned.

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?

Two sentences, zero filler, with the resource definition front-loaded and the usage guidance immediately after. Every clause 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?

No output schema exists, so the description must signal what comes back; it does ('itemised price', 'exact total and the amount payable now'). Combined with rich schema documentation and annotations, an agent has what it needs, though a note on whether the quote expires or holds inventory would close the last gap.

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 100%, with every parameter and the nested extras fields documented in the schema itself, including conditional rules (infants only where age_policy allows, child age varies by campsite). The description only restates extras/discount/voucher at a high level, adding no syntax or format beyond the schema, so 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?

States a specific verb+resource ('An itemised price for one accommodation, stay and party') and scopes exactly what inputs are priced (extras, discount/voucher code). It implicitly distinguishes itself from start_booking by framing it as the pre-booking step, though it never names check_availability or get_campsite directly.

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?

Gives clear context: 'Use it to show the guest the exact total and the amount payable now before starting the booking.' This states when to reach for it and where it sits in the sequence. It does not explicitly exclude alternatives (e.g. that it does not reserve inventory), leaving some inference.

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