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

Annotations already establish that this is a read-only, idempotent, non-destructive operation. The description adds useful behavioral context by saying it defaults to the lowest current captured two-adult offer, that occupancy is explicit per offer, and that live or family quotes are not included.

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 three short, front-loaded sentences with no wasted text. Constraints, defaults, occupancy behavior, and the live/family exclusion are all communicated efficiently.

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 comparison tool with an output schema and read-only annotations, the description covers the key scope, defaults, and limitations. It does not explain error handling for invalid or unavailable offers, but the essential information needed to invoke the tool correctly is present.

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?

The description clarifies the top-level sailings parameter as two to four distinct sailings and notes that exact offer IDs are optional. The nested schema already documents sailingId, offerId, cabinClass, and eventSelector in detail, while the description adds selection/default meaning around those fields.

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: compare two to four distinct sailings, with optional exact offer IDs. This clearly distinguishes it from single-sailing siblings such as get_sailing and from search-oriented tools like search_cruises.

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 clear usage context: comparison is limited to two to four distinct sailings and uses captured offers by default. It also states an exclusion, 'No live or family quote,' but does not explicitly name alternative sibling tools for those cases.

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