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

Annotations already declare readOnly, idempotent, non-destructive and open-world, so the safety profile is covered. The description adds genuinely non-obvious behavior: the return value is a set of product ids that are wired into get_quote's addons field, and prices accompany them. It does not describe pagination or empty-result behavior, hence not a 5.

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 tight sentences; the core purpose and examples lead, and the hand-off contract with get_quote is front-loaded in the same breath. No filler.

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?

There is no output schema, and the description compensates by explaining the return shape (product ids accepted as addons, plus prices). The main gap is the undocumented destinationId, which an agent must guess at.

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 50% — accommodationTypeId carries a provenance hint in the schema, but destinationId is undocumented in both schema and description. The description implies the pairing of a destination with an accommodation type but adds no format, id source, or constraint detail beyond what the schema already says.

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?

Specific verb (List) plus resource (optional extras for a given accommodation type), with concrete examples of what an extra is and a clear statement of what the results are for. It also differentiates itself by naming the sibling that consumes its output (get_quote).

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?

The description makes the usage context clear: call this to enumerate extras for a specific accommodation type, then feed the returned product ids into get_quote as addons. It does not state exclusions or when this should be skipped in favor of another sibling, so it falls just short of explicit when/when-not guidance.

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