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

The annotations already declare this is not read-only and is destructive, but the description adds important context beyond them: the booking is pending payment, it is only secured when the traveller pays on the payment page, and deposit terms differ between shared and private tours. It does not discuss cancellation, refunds, or irreversible side effects in detail, but the core booking lifecycle is well disclosed.

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 front-loaded with the action and return value, then moves to preconditions and payment mechanics. It is dense and mostly waste-free, though the parenthetical deposit explanation slightly repeats 'paid in cash on the day' for shared and private tours.

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 15-parameter mutation tool with no output schema, the description covers the critical business flow: pending payment, payment link return, traveller_confirmed gating, and deposit/full payment rules. It does not elaborate on duplicate-booking behavior or hotel pickup requirements, but those are already specified in the schema's parameter descriptions.

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, but the description meaningfully expands on the payment parameter: 'full' is default, 'deposit' only when the tour offers it, and the remaining balance is paid in cash. It also reinforces the semantics of traveller_confirmed as the traveller's approval gate, adding value beyond the schema's concise field description.

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 states a specific verb and resource ('Creates a tour booking pending payment') and names the return value ('its reference and a secure payment page on phiphiparadise.travel'). This clearly distinguishes it from sibling tools such as check_availability, search_experiences, and book_transfer.

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 precondition: traveller_confirmed must be true only after the traveller has approved the restated product, date, party, total, and payment. It also explains when deposit payment applies, but it does not explicitly route the agent to check_availability or search_experiences first, nor does it name alternatives.

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