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

Annotations already declare readOnlyHint/idempotentHint, so safety is covered, but the description adds the non-obvious 12-hour notice business rule, the Jamaica-time constraint, and a summary of what is returned (bookability per leg plus earliest bookable time). The trailing 'Read-only' restates the annotation but the rest adds real behavioral context.

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?

Front-loaded with the purpose, then prerequisites, then parameter guidance, then the return summary — a logical order with no filler. It is dense in a single paragraph, but each clause carries actionable 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 compensates by summarizing the return (per-leg bookability and earliest bookable time), and it specifies the exact input format and timezone for all three optional parameters. An agent has everything needed to call it correctly and interpret the result.

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 baseline is 3, but the description adds meaning beyond the schema by disambiguating departure_at (hotel pickup) from departure_flight_at (flight departure, pickup derived from it) and presenting them as alternatives for the return leg. That relational framing is not in the individual property descriptions.

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 and resource — checking whether a pickup can be booked online — with the scope of both legs (arrival and flight home). It is clearly distinguishable from the sibling booking tools (book_and_pay_transfer, start_transfer_booking) because it only checks eligibility rather than transacting.

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 a clear precondition (12 hours' notice in Jamaica time) and explains which parameters apply to which leg, which tells the agent when the tool is applicable. It stops short of naming alternatives or stating exclusions (e.g. 'use book_and_pay_transfer to actually book'), so it is strong context but not a full when/when-not guide.

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